5b6f85-cis888614800295549 conservation of fuel and power

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Conservation of fuel and power

The Building Regulations 2000

L1BL1B Conservation of fuel and power

in existing dwellings

APPROVEDDOCUMENT

2010

ed

ition

Coming into effect 1 October 2010


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Approved Document G Sanitation, hot water saety and water efciency

All references to the Building Regulations 2000(as amended) should be read as references tothe Building Regulations 2010.

All references to the Building (ApprovedInspectors etc.) Regulations 2000 should beread as references to the Building (ApprovedInspectors etc.) Regulations 2010.

There have been no substantive requirementsamendments to either set of regulations, butplease note the simplication of the denition ofroom for residential purposes in regulation 2 ofthe Building Regulations 2010. Please also notethat L1(c) has now become regulation 40.

The following tables will help you to nd the newregulation number for regulations which havebeen re-numbered in the 2010 Regulations. For

any regulation number not included in the tablesbelow, the number of the regulation has not changed.

Amendments to Approved Documents andCompliance Guides 2010


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Building RegulationsRegulationnumberin BuildingRegulations2000

Regulationnumberin BuildingRegulations2010





2(2A) 2(3) 12(7) 12(8) 20AA 42

2(2B) 2(4) 13(2)(c)(iii) 13(2)(ii) 20B 43

2(2C) 2(5) 13(3) deleted 20C(A1) 44(1)

2(3) deleted 13(5) 13(3) 20C(1) 44(2)

3(1)(g) 3(1)(h) 13(6) 13(4) 20C(2) 44(3)

3(1)(h) 3(1)(g) 13(7) 13(5) 20C(3) 44(4)

4(1A) 4(2) 14(3)(aa) 14(3)(b) 20D 27

4(2) 4(3) 14(3)(b) 14(3)(c) 20E 37

4A 23 14A 15 21(1) 18(1)

4B(1) 22 15 16 21(2) 18(8)

4B(2) deleted 16A 20 21(3) 18(2)

6(1)(cc) 6(1)(d) 16B 38 21(4) 18(3)

6(1)(d) 6(1)(e) 16C 39 21(5) 18(4)

6(1)(e) 6(1)(f) 17A 24 21(6) 18(5)

6(1)(f) 6(1)(g) 17B 25 21(7) 18(6)

6(1)(ff) 6(1)(h) 17C 26 21(8) 18(7)

6(1)(g) 6(1)(i) 17D 28 22 47

9(1A) 9(2) 17E(4) 29(5) 22B(1)(a) 48(1)(a)

9(2) 9(3) 17E(5) 29(4) 22B(1)(b) 48(1)(b)

9(3) 21(1) 17F 30 22B(1)(c) 48(1)(c)

9(4) 21(2) 17G 31 22B(1)(d) 48(1)(g)

9(5) 21(3) 17H 32 22B(1)(e) 48(1)(d)

9(5A) 21(4) 17I 33 22B(1)(f) 48(1)(i)

9(6) 21(5) 17J 35 22B(1)(g) 48(1)(j)

12(2) 12(1) 17K 36 22B(1)(h) 48(1)(l)

12(2A) 12(2) 18 45 22B(1)(ha) 48(1)(m)

12(4A) 12(5) 19 46 22B(1)(i) 48(1)(n)

12(5) 12(6) 20 19 22B(1)(j) 48(1)(o)

12(6) 12(7) 20A 41 22B(1)(k) 48(1)(h)

22B(1)(ka) 48(1)(k) J2A J3 J6 J7

22B(1)(l) 48(1)(e) J3 J4 L1(c) Regulation 40

22B(1)(m) 48(1)(f) J4 J5 Schedule 2A Schedule 3

22B(2) 48(2) J5 J6 Schedule 2B Schedule 4


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Building (Approved Inspectors etc.) Regulations

Regulationnumberin Building(ApprovedInspectors etc.)Regulations2000






1 1 and 38 13(1)(d) 12(6)(c) 25(2) 25(3)

3 4 13(2) 12(1) 25(3) 25(4)

4 3 13(3) 12(2) 31A(a) 32(c)

8 10 13(4) 12(3) 31A(b) 32(c)

9 11 13(5) 12(4) 31A(c) 32(e)

10(1) 9(5) 13(6) 12(5) 31A(d) 32(f)

10(2) 9(1) 13A 13 31A(e) 32(h)

10(3) 9(2) 14 14(1) 31A(ea) 32(i)

10(4) 9(3) 15(1) 14(2) 31A(f) 32(j)

10(5) 9(4) 15(2) 14(3) 31A(g) 32(k)

11(1)(a) 8(1)(a) 15(3) 14(4) 31A(h) 32(d)

11(1)(c) 8(1)(b) 16 15 31A(ha) 32(g)11(2) 8(2) 17 16 31A(i) 32(a)

11A 20(1) 18(1) 17(1) 31A(j) 32(b)

12 20(1) and (3) 18(2) 17(2) and (3) *Sch 3 7A Sch 2 8

12A 20(1) and (5) 18(3) 17(4) Sch 3 8 Sch 2 9

12AA 20(1) 18(4) 17(5) Sch 3 9 Sch 2 10

12B 20(1) 18(5) 17(6) Sch 4 7A Sch 3 8

12C 20(1) and (6) 18(6) 17(7) Sch 4 8 Sch 3 9

12D 20(1) and (2) 19 18 Sch 6 5A Sch 5 6

12E 20(1) and (4) 20 19 Sch 6 6 Sch 6 7

13(1) 12(6) 23A 24

13(1)(b) 12(6)(a) 24 25(1)13(1)(c) 12(6)(b) 25(1) 25(2)

Please note that some of the numbering and cross referencing in the forms in Schedule 1 has changed slightly.

*Sch =Schedule


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MAIN CHANGES IN THE

2010 EDITION1. This Approved Document L1B comes into force

on 1 October 2010 in support of the Buildingand Approved Inspectors (Amendment)Regulations 2010, SI 2010 No. 719. The mainchanges to the legal requirements and thesupporting guidance in this edition ofApproved Document L1B are as follows:

Changes in the legal requirements

2. The exemption from the energy efficiencyprovisions for extensions consisting of aconservatory or porch is amended to grantthe exemption only where any existing walls,windows or doors are retained, or replaced ifremoved, and where the heating system ofthe building is not extended into theconservatory or porch.

3. The list of work in Schedule 2B (work thatneed not be notified to building control) isamended to include the installation of

thermal insulation in a roof space or loftspace where this is the only work carried outand the work is not carried out to complywith any requirement in the BuildingRegulations.

Changes in the technical guidance

4. In this Approved Document the guidance isgenerally based upon an elemental approachto demonstrating compliance, with additionalguidance that provides greater flexibility. Themain technical changes comprise a generalstrengthening of energy efficiency standardsthat are considered reasonable for work on

thermal elements, controlled fittings andcontrolled services in existing dwellings.

5. Amended guidance is given for historic andtraditional buildings which may have anexemption from the energy efficiencyrequirements or where special considerationsapply.

6. Amended guidance is given where anextension is a conservatory or porch that isnot exempt from the energy efficiencyrequirements.

7. The guidance for the renovation of a thermalelement through the provision of a new layer

or through the replacement of an existinglayer has been expanded.

8. Guidance is provided for swimming poolbasins (walls and floor) in existing dwellings.


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Approved Document L1B Conservation of fuel and power

PAGE

Section 1: Introduction 2

What is an Approved Document? 2

Consideration of technical risk 2

How to use this Approved Document 2

Where you can get further help 3

Responsibility for compliance 3

Section 2: The requirements 4

LIMITATION ON REQUIREMENTS 6

Section 3: General guidance 7

Key terms 7

Types of work covered by this

Approved Document 8Dwellings within the scope of theenergy efciency requirements 8

Dwellings exempt from the energyefciency requirements 8

Notication of work covered by theenergy efciency requirements 9

Materials and workmanship 10

The Workplace (Health, Safety andWelfare) Regulations 1992 11

Section 4: Guidance relating tobuilding work 12

THE EXTENSION OF A DWELLING 12

Reference method 12

Optional approaches with moredesign exibility 12

Conservatories and porches 12

Swimming pool basins 13

MATERIAL CHANGE OF USE ANDCHANGE OF ENERGY STATUS 13

Material change of use 13

Change of energy status 13

Option providing more design exibility 14

WORK ON CONTROLLED FITTINGSAND SERVICES 14

Controlled ttings 14

Controlled services 14

COMMISSIONING OF FIXED BUILDINGSERVICES 15

PAGE

Section 5: Guidance on thermal elements 17

THE PROVISION OF THERMAL ELEMENTS 17

U-values 17

Continuity of insulation and airtightness 17

RENOVATION OF THERMAL ELEMENTS 17

RETAINED THERMAL ELEMENTS 18

Section 6: Consequential improvements toenergy performance 19

Section 7: Providing information 20

Appendix A: Work to thermal elements 21

Appendix B: Documents referred to 24

Appendix C: Standards referred to 25

Contents L1B


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L1B

Conservation of fuel and power Approved Document L1B

2

Section 1: Introduction

What is an Approved Document?

1.1 This Approved Document, which takeseffect on 1 October 2010 has been approvedand issued by the Secretary of State to providepractical guidance on ways of complying with the

energy eiciency requirements (see Section 2)and regulation 7 of the Building Regulations 2000(SI 2000/2531) for England and Wales, as amended.Regulation 2(1) of the Building Regulationsdefines the energy eiciency requirementsas the requirements of regulations 4A, 17C, 17Dand 17E and Part L of Schedule 1. The BuildingRegulations 2000 are referred to throughout theremainder of this Document as the BuildingRegulations.

1.2 The intention of issuing Approved Documentsis to provide guidance about compliance withspecific aspects of building regulations in some

of the more common building situations. Theyset out what, in ordinary circumstances, may beaccepted as reasonable provision for compliancewith the relevant requirement(s) of buildingregulations to which they refer.

1.3 If guidance in an Approved Documentis followed there will be a presumption ofcompliance with the requirement(s) covered bythe guidance. However, this presumption can beoverturned, so simply following guidance doesnot guarantee compliance; for example, if theparticular case is unusual in some way, thennormal guidance may not be applicable. It is

also important to note that there may well beother ways of achieving compliance with therequirements. There is therefore no obligationto adopt any particular solution contained inthis Approved Document if you would preferto meet the relevant requirement in someother way. Persons intending to carry outbuilding work should always check with theirbuilding control body, either the local authorityor an approved inspector, that their proposalscomply with building regulations.

1.4 It is important to note that this ApprovedDocument, as well as containing guidance, also

contains extracts from the Regulations. Suchregulatory text must be complied with as stated.For example, the requirement that ixed buildingservices must be commissioned (regulation 20C)is a regulatory requirement. There is therefore noflexibility to ignore this requirement; neither cancompliance with this particular regulation bedemonstrated via any route other than that setout in regulation 20C.

1.5 The guidance contained in this ApprovedDocument relates only to the particularrequirements of the Building Regulations that thedocument addresses (set out in Section 2).

However, building work may be subject to morethan one requirement of building regulations. Insuch cases the work will also have to comply

with any other applicable requirements ofbuilding regulations.

1.6 There are Approved Documents that giveguidance on each of the Parts of Schedule 1 andon regulation 7. A full list of these is provided at

the back of this document.

Consideration of technical risk

1.7 Building work to existing dwellings mustsatisfy all the technical requirements set outin regulations 4A, 4B, 17D and 17E of, andSchedule 1 to, the Building Regulations. Whenconsidering the incorporation of energy efficiencymeasures in dwellings, attention should alsobe paid in particular to the need to comply withPart B (fire safety), Part C (site preparation andresistance to contaminants and moisture), Part E(resistance to the passage of sound), Part F

(ventilation), paragraph G3 (hot water supply andsystems), Part J (combustion appliances and fuelstorage systems) and Part P (electrical safety)of Schedule 1 to the Building Regulations, aswell as Part L. The adoption of any particularenergy efficiency measure should not involveunacceptable technical risk of, for instance,excessive condensation. Designers and buildersshould refer to the relevant Approved Documentsand to other generally available good practiceguidance to help minimise these risks.

How to use this Approved Document

1.8 This Approved Document is subdividedinto seven sections as detailed below. Thesesections are followed by supporting appendices.

This introductorysection sets out the generalcontext in which the guidance in this ApprovedDocument must be considered.

Section 2 sets out the relevant legal requirementscontained in the Building Regulations.

Section 3 contains general guidance, includingthe definition of key terms, the types of buildingwork covered by this Approved Document,the types of building work that are exempt,

procedures for notifying work, materials andworkmanship and health and safety issues.

Section 4 gives guidance on reasonableprovision for various types of building work.

Section 5 deals with the particular case of workto thermal elements.

Section 6 gives guidance in support of therequirement for consequential improvementsfor buildings over 1,000 m2.

Section 7 describes the information that shouldbe provided to occupiers to help them achievereasonable standards of energy efficiency inpractice.


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INTRODUCTION L1B

1.9 In this document the following conventionshave been adopted to assist understanding andinterpretation:

a. Texts shown against a green background areextracts from the Building Regulations orBuilding (Approved Inspectors etc.) Regulations2000 (SI 2000/2532) (the ApprovedInspectors Regulations), both as amended,and set out the legal requirements that relateto compliance with the energy eiciencyrequirements of building regulations. As statedpreviously, there is no flexibility in respectof such text; it defines a legal requirement,not guidance for typical situations. It shouldalso be remembered that, as noted above,building works must comply with all the otherapplicable requirements of building regulations.

b. Key terms are defined in paragraph 3.1 andare printed inbold italic text.

c. Details of technical publications referred to

in the text of this Approved Document will begiven in footnotes and repeated as referencesat the end of the document. A reference to apublication is likely to be made for one of twomain reasons. The publication may containadditional or more comprehensive technicaldetail, which it would be impractical toinclude in full in the Approved Document butwhich is needed to fully explain ways ofmeeting the requirements; or it is a source ofmore general information. The reason for thereference will be indicated in each case. Thereference will be to a specified edition of thedocument. The Approved Document may beamended from time to time to include newreferences or to refer to revised editionswhere this aids compliance.

d. Additional commentary in italic textappearsafter some numbered paragraphs. Thiscommentary is intended to assist understandingof the immediately preceding paragraph orsub-paragraph, or to direct readers tosources of additional information, but is notpart of the technical guidance itself.

Where you can get further help

1.10 If you do not understand the technicalguidance or other information set out in thisApproved Document and the additional detailedtechnical references to which it directs you, thereare a number of routes through which you canseek further assistance:

the CLG website: www.communities.gov.uk;

the Planning Portal website:www.planningportal.gov.uk;

if you are the person undertaking the buildingwork, you can seek assistance either fromyour local authority building control service or

from your approved inspector (depending onwhich building control service you are using;

persons registered with a competent personself-certication scheme may be able to gettechnical advice from their scheme operator;

if your query is of a highly technical nature,you may wish to seek the advice of aspecialist, or industry technical body, forthe relevant subject.

Responsibility for compliance1.11 It is important to remember that if youare the person (e.g. designer, builder, installer)carrying out building work to which anyrequirement of building regulations applies youhave a responsibility to ensure that the workcomplies with any such requirement. The buildingowner may also have a responsibility for ensuringcompliance with building regulation requirementsand could be served with an enforcement noticein cases of non-compliance.


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L1B

2.1 This Approved Document, which takeseffect on 1 October 2010, deals with the energyeiciency requirements in the Building Regulations(as amended). Regulation 2(1) of the BuildingRegulations defines the energy eiciencyrequirements as the requirements of regulations4A, 17C, 17D and 17E and Part L of Schedule 1.The energy eiciency requirements relevantto existing dwellings are in regulations 4A, 17Dand 17E of, and Part L of Schedule 1 to, thoseRegulations, as set out below.

Requirements relating to thermal elements Regulation 4A

(1) Where a person intends to renovate a thermal element,

suchworkshallbecarriedoutasisnecessarytoensurethatthe

whole thermal element complies with the requirements of

paragraphL1(a)(i)ofSchedule1.

(2) Where a thermal element is replaced, the new thermal

elementshallcomplywiththerequirementsofparagraphL1(a)

(i)ofSchedule1.

Consequential improvements to energy Regulation 17D

(1) Paragraph(2)applies toanexistingbuildingwithatotal

useful floor areaover 1000m2 where theproposedbuilding

workconsistsoforincludes

(a) anextension;

(b) theinitialprovisionofanyfixedbuildingservices;or

(c) an increase to the installed capacity of any fixedbuildingservices.

(2) Subject to paragraph (3), where this paragraph applies,

suchwork,ifany,shallbecarriedoutasisnecessarytoensure

thatthebuildingcomplieswiththerequirementsofPartLof

Schedule1.

(3) Nothinginparagraph(2)requiresworktobecarriedoutif

itisnottechnically,functionallyoreconomicallyfeasible.

Energy perormance certifcates Regulation 17E

(1) Thisregulationapplieswhere

(a) abuildingiserected;or

(b) abuildingismodifiedsothatithasagreaterorfewer

numberofpartsdesignedor altered for separateusethanit

previouslyhad,wherethemodif icationincludestheprovision

orextensionofanyofthefixedservicesforheating,hotwater,

airconditioningormechanicalventilation.

(2) Thepersoncarryingouttheworkshall

(a) giveanenergyperformancecertificateforthebuilding

totheownerofthebuilding;and

(b) give to the local authority notice to that effect,

including the reference number under which the energy

performancecertificatehasbeenregisteredinaccordancewith

regulation17F(4).

Section 2: The requirements


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THE REQUIREMENTS L1B

Energy perormance certifcates Regulation 17E (continued)

(3) The energy performance certificate and notice shall be

givennotlaterthanfivedaysaftertheworkhasbeencompleted.

(4) Theenergyperformancecertificatemustbeaccompanied

bya recommendationreport containingrecommendations for

theimprovement ofthe energyperformanceof thebuilding,

issued by the energy assessor who issued the energy

performancecertificate.

(5) Anenergyperformancecertificatemust

(a) express the asset rating of the building in a way

approvedbytheSecretaryofStateunderregulation17A;

(b) include a reference value such as a current legal

standardorbenchmark;

(c) beissuedbyanenergyassessorwhoisaccreditedto

produce energyperformancecertificates for thatcategoryof

building;and

(d) includethefollowinginformation

(i) thereferencenumberunderwhichthecertificate

hasbeenregisteredinaccordancewithregulation17F(4);

(ii) theaddressofthebuilding;

(iii) anestimateofthetotalusefulfloorareaofthe

building;

(iv) thenameoftheenergyassessorwhoissuedit;

(v) the name and address of the energy assessors

employer,or,ifheisself-employed,thenameunderwhichhe

tradesandhisaddress;

(vi) thedateonwhichitwasissued;and

(vii)thenameoftheapprovedaccreditationschemeof

whichtheenergyassessorisamember.

(6) Certificationfor apartmentsor unitsdesignedor alteredforseparateuseinblocksmaybebased

(a) except in the case of a dwelling, on a common

certificationofthewholebuildingforblockswithacommon

heatingsystem;or

(b) ontheassessmentofanotherrepresentativeapartment

orunitinthesameblock.

(7) Where

(a) ablockwithacommonheatingsystemisdividedinto

partsdesignedoralteredforseparateuse;and

(b) oneormore,butnotall,ofthepartsaredwellings,

certication forthose partswhichare notdwellings maybebasedonacommoncerticationofall thepartswhicharenot

dwellings.


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L1B THE REQUIREMENTS

6


Requirement Limitsonapplication

Schedule 1 Part L Conservation o uel and power

L1.Reasonableprovisionshallbemadefortheconservationof

fuelandpowerinbuildingsby:

(a) limitingheatgainsandlosses

(i) throughthermalelementsandotherpartsofthe

buildingfabric;and

(ii) from pipes, ducts and vessels used for space

heating,spacecoolingandhotwaterservices;

(b) providingfixedbuildingserviceswhich

(i) areenergyefficient;

(ii) haveeffectivecontrols;and

(iii) are commissioned by testing and adjusting as

necessarytoensuretheyusenomorefuelandpowerthanis

reasonableinthecircumstances;and

(c) providingto the owner sufficient information aboutthebuilding,thefixedbuildingservicesandtheirmaintenance

requirements sothatthebuildingcanbeoperated insucha

mannerastousenomorefuelandpowerthanisreasonablein

thecircumstances.

LIMITATION ON REQUIREMENTS

2.2 In accordance with regulation 8 of theBuilding Regulations, the requirements in Parts Ato D, F to K and N (except for paragraphs G2, H2and J6) of Schedule 1 to the Building Regulations

do not require anything to be done except for thepurpose of securing reasonable standards ofhealth and safety for persons in or about buildings(and any others who may be affected by buildingsor matters connected with buildings).

2.3 Paragraph G2 is excluded as it deals withwater efficiency and paragraphs H2 and J6 areexcluded from regulation 8 because they dealdirectly with prevention of the contamination ofwater. Parts E and M (which deal, respectively,with resistance to the passage of sound, andaccess to and use of buildings) are excludedfrom regulation 8 because they address the

welfare and convenience of building users. Part Lis excluded from regulation 8 because it addressesthe conservation of fuel and power.

2.4 In addition, regulation 4(1A) of the BuildingRegulations states that where the work is beingcarried out in order to comply with regulation 4A(requirements relating torenovation or replacementof a thermal element), regulation 4B (requirementsrelating to a change of a buildings energy status)or regulation 17D (consequential improvementsto energy performance), and is not a materialalteration, it need comply only with the requirementsof Part L.


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L1B

Key terms

3.1 The following are key terms used in thisdocument:

BCB means Building Control Body: a local

authority or an approved inspector.Commissioning means the advancement ofa ixed building service following installation,replacement or alteration of the whole or partof the system, from the state of static completionto working order by testing and adjusting asnecessary to ensure that the system as a wholeuses no more fuel and power than is reasonable inthe circumstances, without prejudice to the needto comply with health and safety requirements.For each system commissioning includessetting-to-work, regulation (that is testing andadjusting repetitively) to achieve the specified

performance, the calibration, setting up andtesting of the associated automatic controlsystems, and recording of the system settingsand the performance test results that have beenaccepted as satisfactory.

Consequential improvements means thoseenergy efficiency improvements required byregulation 17D.

Controlled service or ftting means a service ortting in relation to which Part G (sanitation, hotwater safety and water efciency), H (drainageand waste disposal), J (combustion appliancesand fuel storage systems), L (conservation of fuel

and power) or P (electrical safety) of Schedule 1to the Building Regulations imposes a requirement.

Dwelling means a self-contained unit, includinga house or a flat, designed to be used separatelyto accommodate a single household. (Rooms orresidential purposes are not dwellings so ApprovedDocument L2B applies to work in such buildings.)

Energy efciency requirements means therequirements of regulations 4A, 17C, 17D and17E of, and Part L of Schedule 1 to, the BuildingRegulations.

In respect of existing dwellings the applicablerequirements consist of Part L and regulations 4Aand 17D.

Fixed building services means any part of, orany controls associated with:

a. fixed internal or external lighting systems, butdoes not include emergency escape lightingor specialist process lighting; or

b. fixed systems for heating, hot water, airconditioning, or mechanical ventilation.

Room or residential purposes means a room, or

a suite of rooms, which is not a dwelling-house or aflat and which is used by one or more persons tolive and sleep and includes a room in a hostel, anhotel, a boarding house, a hall of residence or a

residential home, whether or not the room isseparated from or arranged in a cluster group withother rooms, but does not include a room in ahospital, or other similar establishment, used forpatient accommodation and, for the purposes ofthis definition, a cluster is a group of rooms forresidential purposes which is:

a. separated from the rest of the building in whichit is situated by a door which is designed to belocked; and

b. not designed to be occupied by a singlehousehold.

Renovationin relation to a thermal elementmeans the provision of a new layer in the thermalelement or the replacement of an existing layer,but excludes decorative nishes, and renovateshall be construed accordingly.

Simple paybackmeans the amount of time itwill take to recover the initial investment throughenergy savings, and is calculated by dividingthe marginal additional cost of implementing anenergy efficiency measure by the value of theannual energy savings achieved by that measuretaking no account of VAT. When making thiscalculation the following guidance should be used:

a. the marginal additional cost is the additionalcost (materials and labour) of incorporating(e.g.) additional insulation, not the whole costof the work;

b. the cost of implementing the measure shouldbe based on prices current at the date theproposals are made known to theBCB andbe confirmed in a report signed by a suitablyqualified person;

c. the annual energy savings should beestimated using SAP 20091;

d. for the purposes of this Approved Document,the energy prices that are current at the timeof the application to building control shouldbe used when evaluating the annual energysavings. Current energy prices can be obtainedfrom the DECC website2.

Thermal elementis defined in regulation 2(2A)of the Building Regulations as follows:

(2A) In these Regulations thermal elementmeans a wall, oor or roof (but does not includewindows, doors, roof windows or roof-lights)which separates a thermally conditioned part ofthe building (the conditioned space) from:

a. the external environment (including theground); or

b. in the case of floors and walls, anotherpart of the building which is:

i. unconditioned;

1 www.bre.co.uk/sap20092 www.decc.gov.uk/en/content/cms/statistics/publication/prices/prices.aspx

Section 3: General guidance


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L1B GENERAL GUIDANCE

ii. an extension falling within class VII inSchedule 2; or

iii. where this paragraph applies, conditionedto a different temperature,

and includes all parts of the element between thesurface bounding the conditioned space and theexternal environment or other part of the building

as the case may be.(2B) Paragraph (2A)(b)(iii) only applies to abuilding which is not a dwelling, where the otherpart of the building is used for a purpose whichis not similar or identical to the purpose for whichthe conditioned space is used.

Note that this definition encompasses the wallsand floor of a swimming pool basin where this ispart of an existing dwelling.

Types of work covered by this

Approved Document

3.2 This Approved Document is intended togive guidance on what, in ordinary circumstances,may be considered reasonable provision forcompliance with the requirements of regulation4A and 17D of, and Part L of Schedule 1 to, theBuilding Regulations for those carrying outbuilding work to existing dwellings. In addition itgives guidance on compliance with regulations20B, 20C and 20D of the Building Regulationsand 12B, 12C and 12D of the Building (ApprovedInspectors etc) Regulations 2000 (SI 2000/2532)(the Approved Inspectors Regulations).

Buildings exclusively containingrooms orresidential purposes such as nursing homes,student accommodation and similar are notdwellings, and in such cases ApprovedDocument L2B applies.

3.3 In particular, this Approved Documentgives guidance on compliance with the energyeiciency requirements where the followingoccurs:

a. the construction of an extension (seeparagraphs 4.1 to 4.9);

b. a material change of use, or a change to the

buildings energy status, including such workas loft and garage conversions (paragraphs4.11 to 4.16);

c. the provision or extension of a controlledservice or controlled itting (paragraphs4.17 to 4.37);

d. the replacement orrenovation of a thermalelement(Section 5);

3.4 Where the activities include building workin a dwelling that is part of a mixed-use building,account should also be taken of the guidance inApproved Document L2B in relation to those

parts of the building that are not dwellings,including any common areas.

It should be noted thatdwellings are definedas self-contained units.Rooms or residential

purposes are notdwellings, and so ApprovedDocument L2B applies to them.

Dwellings within the scope of the

Energy Efficiency Requirements

3.5 The energy eiciency requirements ofthe Building Regulations apply only to buildings

which are roofed constructions having walls andwhich use energy to condition the indoor climate.For dwellings the requirements will apply to:

the erection of a dwelling (guidance on this isgiven in Approved Document L1A);

the extension of a dwelling other than someextensions falling within Class VII in Schedule2 to the Building Regulations; or

the carrying out of any building work to or inconnection with an existing dwelling or anextension to an existing dwelling.

Dwellings exempt from theEnergy Efficiency requirements

3.6 There are two exemptions from the energyefciency requirements that may apply tobuilding work to existing dwellings or extensionsto existing dwellings:

a. Buildings which are:

listed in accordance with section 1 ofthe Planning (Listed Buildings andConservation Areas) Act 1990;

in a conservation area designated in

accordance with section 69 of that Act; or included in the schedule of monuments

maintained under section 1 of the AncientMonuments and Archaeological AreasAct 1979.

For these buildings the exemption appliesonly to the extent that compliance with theenergy efciency requirements wouldunacceptably alter the character orappearance of such existing dwellings.Guidance on these buildings is given inparagraphs 3.7 to 3.14 below.

b. Carports, covered yards, covered ways andsome conservatories or porches attached toexisting dwellings. Guidance on these isgiven at paragraphs 3.15 and 3.16 below.

Historic and traditional buildings which mayhave an exemption

3.7 As mentioned above in paragraph 3.6a, thefollowing classes of buildings have an exemptionfrom the energy eiciency requirements wherecompliance would unacceptably alter thecharacter or appearance of the buildings.

a. listed buildings;

b. buildings in conservation areas; and

c. scheduled ancient monuments.


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GENERAL GUIDANCE L1B

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Historic and traditional buildingswherespecial considerations may apply

3.8 There are three further classes of buildingswhere special considerations in making reasonableprovision for the conservation of fuel or powermay apply:

a. buildings which are of architectural and

historical interest and which are referred to asa material consideration in a local authoritysdevelopment plan or local developmentframework;

b. buildings which are of architectural andhistorical interest within national parks, areasof outstanding natural beauty, registeredhistoric parks and gardens, registeredbattlefields, the curtilages of scheduledancient monuments, and world heritage sites;

c. buildings of traditional construction withpermeable fabric that both absorbs andreadily allows the evaporation of moisture.

3.9 When undertaking work on or inconnection with a building that falls within oneof the classes listed above, the aim should be toimprove energy efficiency as far as is reasonablypracticable. The work should not prejudice thecharacter of the host building or increase the riskof long-term deterioration of the building fabricor fittings.

3.10 The guidance given by English Heritage3should be taken into account in determiningappropriate energy performance standards forbuilding work in historic buildings.

3.11 In general, new extensions to historic ortraditional dwellings should comply with thestandards of energy efficiency as set out in thisApproved Document. The only exception wouldbe where there is a particular need to matchthe external appearance or character of theextension to that of the host building (seeparagraph 4.2).

3.12 Particular issues relating to work in historicbuildings that warrant sympathetic treatment andwhere advice from others could therefore bebeneficial include:

a. restoring the historic character of a buildingthat has been subject to previousinappropriate alteration, e.g. replacementwindows, doors and rooflights;

b. rebuilding a former historic building (e.g.following a fire or filling a gap site in a terrace);

c. making provisions enabling the fabric of historicbuildings to breathe to control moisture andpotential long-term decay problems.

3.13 In assessing reasonable provision forenergy efficiency improvements for historicbuildings of the sort described in paragraphs 3.7

and 3.8, it is important that theBCB takes intoaccount the advice of the local authoritys

3 www.english-heritage.org.uk/

conservation officer. The views of the conservationofficer are particularly important where buildingwork requires planning permission and/or listedbuilding consent.

3.14 Other classes of buildings to which specialconsiderations apply are usually non-domestic incharacter, and so are covered in ADL2A andADL2B.

Conservatories and porches

3.15 Regulation 9 of the Building Regulationsexempts some conservatory and porch extensionsfrom the energy eiciency requirements. Theexemption applies only for conservatories or porches:

which are at ground level;

where the floor area is less than 30 m2;

where the existing walls, doors and windowsin the part of the dwelling which separatesthe conservatory are retained or, if removed,replaced by walls, windows and doors whichmeet the energy eiciency requirements; and

where the heating system of the dwelling isnot extended into the conservatory or porch.

3.16 Where any conservatory or porch doesnot meet all the requirements in the precedingparagraph, it is not exempt and must complywith the relevant energy eiciency requirements(see paragraphs 4.8 and 4.9 below).

Notification of work covered by

the Energy Efficiency requirements

3.17 In most instances in order to comply withthe Building Regulations it will be necessary tonotify aBCB before the work starts. Where youchoose to use the local authority and any workrelates to the common parts of a block of flats,this must be by deposit of full plans. For otherexisting dwellings this could be either in the formof a deposit of full plans or by a building notice.There is no set procedure where theBCB is anApproved Inspector provided they have beennotified at least 5 days before work starting.

3.18 In certain situations, however, you do notneed to notify aBCB:

a. Where the work is being carried out by aperson registered with a relevant competentperson self-certification scheme listed inSchedule 2A to the Building Regulations, noadvance notification to theBCB is needed(see paragraphs 3.19 to 3.22).

b. Where the work involves an emergency repair,e.g. to a failed boiler or a leaking hot watercylinder, in accordance with regulation 12(7)of the Building Regulations there is no needto delay making the repair in order to makean advance notification to theBCB. However,in such cases it will still be necessary for thework to comply with the relevant requirementsand to give a notice to theBCB at the earliestopportunity, unless an installer registered under


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L1B GENERAL GUIDANCE

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an appropriate competent person schemecarries out the work. A completion certificatecan then be issued in the normal way.

c. Where the work is of a minor nature asdescribed in the schedule of non-notifiablework (Schedule 2B to the Building Regulations),the work must still comply with the relevantrequirements but need not be notified to theBCB (see paragraphs 3.23 to 3.25).

Competent person self-certification schemes

3.19 It is not necessary to notify aBCB inadvance of work which is to be carried out bya person registered with a competent personself-certification scheme listed in Schedule 2A tothe Building Regulations. In order to join such ascheme a person must demonstrate competenceto carry out the type of work the scheme covers,and also the ability to comply with all relevantrequirements in the Building Regulations.

3.20 Where work is carried out by a personregistered with a competent person scheme,regulation 16A of the Building Regulations 2000and regulation 11A of the Building (ApprovedInspectors etc) Regulations 2000 require that theoccupier of the building be given, within 30 days ofthe completion of the work, a certificate confirmingthat the work complies fully with all applicablebuilding regulation requirements. There is also arequirement to give theBCB a notice of the workcarried out, again within 30 days of the completionof the work. These certificates and notices areusually made available through the scheme operator.

3.21 BCBs are authorised to accept thesecertificates and notices as evidence of compliancewith the requirements of the Building Regulations.Local authority inspection and enforcementpowers remain unaffected, although they arenormally used only in response to a complaintthat work does not comply.

3.22 A list of authorised self-certification schemesand the types of work for which they are authorisedcan be found at www.communities.gov.uk

Work which need not be notified

3.23 Schedule 2B to the Building Regulations

sets out types of work where there is no requirementto notify aBCB that work is to be carried out.These types of work are mainly of a minor naturewhere there is no significant risk to health, safetyor energy efficiency. Note that the health, safetyand energy eiciency requirements continue toapply to these types of work, and that only theneed to notify aBCB has been removed. In addition,where only non-notifiable work is carried out by amember of a competent person self-certificationscheme there is no requirement for a certificateof building regulations compliance to be given tothe occupier or theBCB.

3.24 The types of non-notifiable work inSchedule 2B relevant to the energy eiciencyrequirements of the Regulations are:

a. In a heating, hot water, ventilation or air-

conditioning system, the replacement of anypart which is not a combustion appliance(such as a radiator, valve or pump) or theaddition of an output device (such as aradiator or fan) or the addition of a controldevice (such as a thermostatic radiator valve).However, the work will remain notifiablewhenever commissioning is possible and

necessary to enable a reasonable use of fueland power (see paragraphs 4.30 to 4.37).

b. The installation of a stand-alone, self-contained fixed heating, hot water, ventilationor air-conditioning service. Such servicesmust consist only of a single appliance andany associated controls, and must not beconnected to, or form part of, any other ixedbuilding service. Examples of non-notifiableservices would be a fixed electric heater, amechanical extractor fan in a kitchen orbathroom, and a room air-conditioning unit.However, if any of the following apply, the

work will remain notifiable building work:i. the service is a combustion appliance;

ii. any electrical work associated with theinstallation is notifiable;

iii. commissioning is possible and wouldaffect the services energy efficiency (seeparagraphs 4.30 to 4.38);

iv. in the case of a ventilation appliance, theappliance is installed in a room containinga natural draught open-flued combustionappliance or service, such as a gas firewhich uses a chimney as its flue.

c. Installation of thermal insulation in a roofspace or loft space where this is the onlywork carried out and the work is not carriedout to comply with any requirement in theBuilding Regulations, i.e. the work is carriedout voluntarily.

3.25 Schedule 2B also sets out what typesof electrical installation work in dwellings arenon-notifiable. Full information on this is givenin Approved Document P.

Materials and workmanship

3.26 Any building work which is subject to therequirements imposed by Schedule 1 to theBuilding Regulations should, in accordance withregulation 7, be carried out with proper materialsand in a workmanlike manner.

3.27 You may show that you have compliedwith regulation 7 in a number of ways. Theseinclude demonstrating the appropriate use of:

a product bearing CE marking in accordancewith the Construction Products Directive(89/106/EC)4 as amended by the CE MarkingDirective (93/68/EC)5, the Low Voltage

4 AsimplementedbytheConstructionProductsRegulations1991

(SI1991/1620).5 AsimplementedbytheConstructionProducts(Amendment)Regulations

1994(SI1994/3051).


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GENERAL GUIDANCE L1B

11


Directive (2006/95/EC)6 and the EMCDirective (2004/108/ EC)7;

a product complying with an appropriatetechnical specication (as dened in thoseDirectives mentioned above), a BritishStandard, or an alternative national technicalspecication of a Member State of theEuropean Union or Turkey 8, or of anotherState signatory to the Agreement on theEuropean Economic Area (EEA) that providesan equivalent level of safety and protection;

a product covered by a national or Europeancerticate issued by a European TechnicalApproval Issuing body, provided theconditions of use are in accordance with theterms of the certicate.

3.28 You will find further guidance in theApproved Document which specifically supportsregulation 7 on materials and workmanship.

Independent certification schemes3.29 There are many UK product certificationschemes. Such schemes certify compliance withthe requirements of a recognised standard that isappropriate to the purpose for which the materialis to be used. Materials which are not so certifiedmay still conform to a relevant standard.

3.30 Many certification bodies that approveproducts under such schemes are accreditedby the United Kingdom Accreditation Service(UKAS). Such bodies can issue certificates onlyfor the categories of product covered under theterms of their accreditation.

3.31 BCBs may take into account thecertification of products, components, materialsor structures under such schemes as evidence ofcompliance with the relevant standard. Similarly,BCBs may accept the certification of the installationor maintenance of products, components,materials or structures under such schemes asevidence of compliance with the relevant standard.Nonetheless, before accepting that certificationconstitutes compliance with building regulations,aBCB should establish in advance that therelevant scheme is adequate for that purpose.

Standards and technical specifications3.32 Building regulations are made for specificpurposes including: securing the health, safety,welfare and convenience of people in or aboutbuildings; furthering the conservation of fuel andpower; furthering the protection or enhancementof the environment; and facilitating sustainabledevelopment. Guidance contained in standardsand technical approvals referred to in ApprovedDocuments may be relevant to compliance withbuilding regulations to the extent that it relates tothose purposes. However, it should be noted thatguidance in standards and technical approvals

6 AsimplementedbytheElectricalEquipment(Safety)Regulations1994

(SI1994/3260).7 AsimplementedbytheElectromagneticCompatibilityRegulations2006

(SI2006/3418).8 DecisionNo1/95oftheECTurkeyAssociationCouncilof22December1995.

may also address other aspects of performancesuch as serviceability, or aspects which, althoughthey relate to health and safety, are not coveredby building regulations.

3.33 When an Approved Document makesreference to a named standard or document therelevant version of the standard or document isthe one listed at the end of the ApprovedDocument. Until the reference in the ApprovedDocument is revised, the standard or documentlisted remains the approved source, but if theissuing body has published a revised or updatedversion, any content that addresses the relevantrequirements of the Building Regulations may beused as a source of guidance.

3.34 The appropriate use of a product thatcomplies with a European Technical Approval asdefined in the Construction Products Directivewill meet the relevant requirements.

3.35 Communities and Local Government intends

to issue periodic amendments to its ApprovedDocuments to reflect emerging harmonisedEuropean standards. Where a national standardis to be replaced by a European harmonisedstandard, there will be a coexistence periodduring which either standard may be referred to.At the end of the coexistence period the nationalstandard will be withdrawn.

The Workplace (Health, Safety and

Welfare) Regulations 1992

3.36 The Workplace (Health, Safety andWelfare) Regulations 1992, as amended, apply tothe common parts of flats and similar buildings ifpeople such as cleaners, wardens and caretakersare employed to work in these common parts.These Regulations contain some requirementswhich affect building design. The main requirementsare now covered by the Building Regulations,but for further information see Workplace health,safety and welfare, Workplace (Health, Safety andWelfare) Regulations 1992, Approved Code ofPractice and guidance, HSE publication L24, 1996.

3.37 Where the requirements of the BuildingRegulations that are covered by this ApprovedDocument do not apply to dwellings, theprovisions may still be required in the situationsdescribed above in order to satisfy the WorkplaceRegulations.


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THE EXTENSION OF A DWELLING

Reference method

Fabric standards

4.1 Reasonable provision would be for theproposed extension to incorporate the following:

a. newly constructed thermal elements thatmeet the standards set out in paragraphs 5.1to 5.6;

b. doors, windows, roof windows and rooflightsthat meet the standards set out in paragraphs4.19 to 4.23;

c. improvements to fabric elements that are tobecome thermal elements, following theguidance in paragraphs 5.6 to 5.11.

Area of windows, roof windows and doors4.2 In most circumstances reasonableprovision would be to limit the total area ofwindows, roof windows and doors in extensionsso that it does not exceed the sum of:

a. 25 per cent of the floor area of the extension;plus

b. the total area of any windows or doors which,as a result of the extension works, no longerexist or are no longer exposed.

As a general guide, if the area of glazing is muchless than 20 per cent of the total floor area, some

parts of the extension and especially the part ofthe dwelling it covers may experience poor levelsof daylight, resulting in increased use of electriclighting. Areas of glazing greater than 25 per centmay be acceptable, especially if this is required tomake the extension consistent with the externalappearance or character of the host building.In such cases and where practical, either theU-value of the window should be improvedrelative to the standard set out in paragraph4.1b, or other compensating measures appliedfollowing the guidance set out in paragraphs4.4 to 4.7.

Heating and lighting in the extension

4.3 Where a ixed building service isprovided or extended as part of constructing theextension, reasonable provision would be tofollow the guidance in paragraphs 4.26 to 4.39.

Optional approaches with more

design flexibility

4.4 The approach set out in paragraphs 4.1to 4.3 is somewhat prescriptive. The followingparagraphs offer more flexible approaches to

demonstrating that reasonable provision hasbeen made. These alternative approaches allowsome elements of the design to be relaxedthrough compensating measures elsewhere.

Area-weighted U-value method

4.5 One way of complying would be toshow that the area-weighted U-value of all theelements in the extension is no greater than thatof an extension of the same size and shape that

complies with the fabric standards referred to inparagraph 4.1 and the opening area standardsin paragraph 4.2. Any ixed building serviceprovided or extended as part of constructingthe extension should follow the guidance inparagraphs 4.24 to 4.37.

The area-weighted U-value is give by thefollowing expression:

{(U1 A1) (U2 x A2) (U3 x A3) )}4 {(A1 A2 A3 )}

Whole dwelling calculation method

4.6 Where even greater design flexibility isrequired, reasonable provision would be to useSAP 2009 to show that the calculated carbondioxide (CO

2) emission rate from the dwelling

with its proposed extension is no greater than forthe dwelling plus a notional extension built to thestandards of paragraphs 4.1 to 4.3. The openingsin the notional extension should conform withparagraph 4.2 with door area set equal to thedoor area of the proposed extension, with theremainder of the openings being classified aswindows. The data in SAP 2009 Appendix Scan be used to estimate the performance of theelements of the existing building where these

are unknown.

Approved Document C gives limiting values forindividual elements to minimise condensation risk.

4.7 If, as part of achieving the standard set outin paragraph 4.6, upgrades are proposed to theexisting dwelling, such upgrades should beimplemented to a standard that is no worse thanset out in the relevant guidance contained in thisApproved Document. The relevant standards forimproving retained thermal elements are as setout in column (b) of Table 3.

Where it is proposed to upgrade the original

building, the standards set out in this ApprovedDocument are cost-effective and should beimplemented in full. It will be worthwhileimplementing them even if the improvement isgreater than necessary to achieve compliance.In some cases, therefore, the standard of theextendeddwelling may be better than thatrequired by paragraph 4.6 alone. Paragraph 4.7sets limits on design flexibility and ensures thatno cost-effective improvement opportunities aretraded away.

Conservatories and porches

4.8 Where the extension is a conservatoryor porch that is not exempt from the energyeiciency requirements (see paragraphs 3.15

Section 4: Guidance relating to building work


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GUIDANCE RELATING TO BUILDING WORK L1B

and 3.16 above), then reasonable provisionwould be to provide:

a. Effective thermal separation between theheated area in the existing dwelling,i.e.the walls, doors, and windows betweenthe dwelling and the extension, should beinsulated and draught proofed to at leastthe same extent as in the existing dwelling.

b. Independent temperature and on/off controlsto any heating system installed within theextension. Any ixed building service installedwithin the extension should also conform to thestandards set out in paragraphs 4.24 to 4.37.

c. Glazed elements should meet the standardsset out in Table 1 and opaque elementsshould meet the standards set out in Table 2.However, the limitations on total area ofwindows, roof windows and doors as setout at paragraph 4.2 above do not apply.

4.9 Removing, and not replacing, any or all ofthe thermal separation between the dwelling andan existing exempt extension, or extending thedwellings heating system into the extension,means the extension ceases to be exempt (seeparagraphs 3.15 and 3.16 above). This constitutesa change to the buildings energy status(Regulation 4B). In such situations, the extensionshould be treated as a conventional extensionand reasonable provision would be to demonstratethat the extension meets the guidance set out inparagraphs 4.1 to 4.7 above.

Swimming pool basins

4.10 Where a swimming pool is being providedin a building, the U-value of the basin (walls andfloor) should be not worse than 0.25 W/m2.K ascalculated according to BS EN ISO 133709.

MATERIAL CHANGE OF USE AND

CHANGE OF ENERGY STATUS

Material change of use

4.11 Material changes of use (see regulation 5of the Building Regulations) covered by thisdocument are where, after the change:

a. the building is used as a dwelling, wherepreviously it was not;

b. the building contains a flat, where previouslyit did not; or

c. the building, which contains at least onedwelling, contains a greater or lesser numberof dwellings than it did previously.

9 BSENISO13370Thermalperformanceofbuildings.Heattransfervia

theground.Calculationmethods.

Change of energy status

4.12 A change to a buildings energy status isdefined in regulation 2(1) as:

any change which results in a building becominga building to which the energy efciencyrequirements of these Regulations apply, wherepreviously it was not.

4.13 The requirements relating to a changeto energy status are in regulation 4B(1):

Where there is a change in a buildings energystatus, such work, if any, shall be carried outto ensure that the building complies with theapplicable requirements of Part L of Schedule 1.

4.14 In this regulation building means thebuilding as a whole or parts of the building thathave been designed or altered to be usedseparately.

For example, this could occur where a previously

unheated building, or parts of the building thathave been designed or altered to be usedseparately, were to be heated in future, or wherea previously exempt building were no longerwithin the exempted categories. A materialalteration (regulation 3(2) and (3)) may resultin a change in buildings energy status.

4.15 In normal circumstances, reasonableprovision where there is a material change ofuse or a change to the buildings energy statuswould be:

a. Where controlled services or ittings are

being provided or extended, to meet thestandards set out in paragraphs 4.17 to 4.37.If the area of openings in the newly createddwelling is more than 25 per cent of the totalfloor area, either the area of openings shouldbe reduced to be not greater than 25 per cent,or the larger area should be compensated forin some other way using the proceduredescribed in paragraph 4.16.

b. Where the work involves the provision of athermal element, to meet the standards setout in paragraphs 5.1 to 5.6.

For the purposes of Building Regulations, provision

means both new and replacement elements.

c. Where any thermal elementis beingretained, to upgrade it following the guidancegiven in paragraphs 5.11 to 5.13.

d. where an existing window (including roofwindow or rooflight) or door which separatesa conditioned space from an unconditionedspace or the external environment has aU-value that is worse than 3.3 W/m2.K, toprovide replacement units following theguidance in paragraphs 4.19 to 4.23.


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Option providing more design

flexibility

4.16 To provide more design flexibility, SAP2009 can be used to demonstrate that the totalCO

2emissions from all the dwellings in the

building as it will become are no greater than ifeach dwelling had been improved following the

guidance set out in paragraph 4.15.

WORK ON CONTROLLED

FITTINGS AND SERVICES

4.17 Controlled services or ittings aredefined in regulation 2 as follows:

Controlled service or fitting means a service orfitting in relation to which Part G, H, J, L or P ofSchedule 1 imposes a requirement;

4.18 In the context of this Approved Document,the application of the term controlled itting to awindow, roof window, rooflight or door refers to awhole unit, i.e. including the frame. Consequently,replacing the glazing whilst retaining an existingframe is not providing a controlled itting, andso such work is not notifiable and does not haveto meet the Part L standards, although wherepractical it would be sensible to do so. Similararguments apply to a new door in an existing frame.

Controlled fittings

4.19 Where windows, roof windows, rooflightsor doors are to be provided, reasonable provision

in normal cases would be the installation ofdraught-proofed units whose performance is noworse than given in Table 1. In addition, insulatedcavity closers should be installed where appropriate.Where the replacement windows are unable tomeet the requirements of Table 1 because of theneed to maintain the external appearance of thefaade or the character of the building, replacementwindows should meet a centre pane U-valueof 1.2W/m2K, or single glazing should besupplemented with low-e secondary glazing. Inthis latter case, the weather stripping should be onthe secondary glazing to minimise condensationrisk between the primary and secondary glazing.

4.20 U-values shall be calculated using themethods and conventions set out in BR 44310,and should be based on the whole unit (i.e. in thecase of a window, the combined performance ofthe glazing and frame). The U-value of thewindow can be calculated for:

a. the smaller of the two standard windowsdefined in BS EN 14351-111; or

b. the standard window configuration set outin BR 443; or

c. the specific size and configuration of theactual window.

10 BR443ConventionsforU-valuecalculations,BRE,2006.11 EN14351-1WindowsanddoorsProductstandard,performance

characteristics,2006.

SAP 2009 Table 6e gives values for differentwindow configurations that can be used in theabsence of test data or calculated values.

4.21 The U-values for roof windows androoflights given in this Approved Document arebased on the U-value having been assessedwith the roof window or rooflight in the verticalposition. If a particular unit has been assessedin a plane other than the vertical, the standardsgiven in this Approved Document should bemodified by making an adjustment that isdependent on the slope of the unit followingthe guidance in BR 443.

Table 1 Standards for controlledfittings

Fitting Standard

Window, roof window orrooflight

WER Band C or better (seeparagraph 4.22), or U-value

1.6 W/m2

.KDoors with >50% of internalface glazed

U-value = 1.8 W/m2.K

Other doors U-value = 1.8 W/m2.K

4.22 The Window Energy Rating (WER) is givenby the following equation;

WER 196.7 ((1 f) gglass) 68.5 (U (0.0165 AL))

Where f is the frame factor i.e the percentage ofthe window obscured by frame and gaskets;

gglass is the normal total solar energy transmittanceof the glass as determined by BS EN 410,

U is the whole window U-value as specied inparagraph 4.20 and 4.21; and

AL is the air leakage through the window inm3/h.m2 at 50 Pa pressure difference based ontesting to BS 63751:2009. Note that AL isbased on the whole window area, not per unitlength of opening light.

The following rating bands dene the windowenergy rating label:

Band A WER >=0Band B 0


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BCBs may accept a WER declaration from acertication scheme that provides a quality-assuredprocess and supporting audit trail from calculatingthe performance of the window through to installationas evidence of compliance. Notwithstanding thesuggested performance values set out above,guidance on energy-efcient windows isavailable from the Energy Saving Trust.12

4.23 If a window is enlarged or a new onecreated, then the area of windows, roof windows,rooflights and doors should not exceed 25 percent of the total floor area of the dwelling unlesscompensating measures are included elsewherein the work.

Controlled services

4.24 Whenever a ixed building service isextended or provided, reasonable provisionwould be demonstrated by following theguidance set out in the Domestic BuildingServices Compliance Guide13. The Guide coversthe following services:

a. heating and hot water systems (includinginsulation of pipes, ducts and vessels;

b. mechanical ventilation;

c. mechanical cooling/air-conditioning;

d. fixed internal lighting;

e. fixed external lighting;

f. renewable energy systems.

4.25 The efficiency claimed for the ixed buildingservice should be based on the appropriate teststandard as set out in the Domestic BuildingServices Compliance Guide and the test datashould be certified by a notified body. It would bereasonable forBCBs to accept such data at facevalue. In the absence of such quality-assureddata,BCBs should satisfy themselves that theclaimed performance is justified.

4.26 When replacing an existing appliance,the efficiency of the new appliance should notbe significantly less than the efficiency of theappliance being replaced. If the replacementinvolves a fuel switch, then the relative carbonemissions associated with the new and existingfuels should be considered when assessing thereasonableness of the proposed new appliance.The Domestic Building Services Compliance Guidecontains the detailed guidance on this issue.

4.27 If a renewable energy generator suchas a wind turbine or photovoltaic array is beingreplaced, the new system should have anelectrical output that is not less than theoriginal installation.

12 http://www.energysavingtrust.org.uk/Home-improvements-and-

products/Home-insulation-glazing/Glazing13 DomesticBuildingServicesComplianceGuide,CLG,2010edition.

4.28 When replacing a heating appliance,consideration should be given to connectingto any existing local heat networks. If the workinvolves pipework changes, consideration shouldbe given to providing capped off connections tofacilitate subsequent connection to a plannedlocal heat network.

4.29 If a particular technology is not coveredin the Domestic Building Services ComplianceGuide, reasonable provision would be demonstratedby showing that the proposed technology givesa performance that is no worse than a referencesystem of the same type whose details are givenin the Guide.

COMMISSIONING OF FIXED

BUILDING SERVICES

4.30 Paragraph L1(b)(iii) of Schedule 1 to theBuilding Regulations requires ixed buildingservices to be commissioned by testing andadjustment as necessary to ensure that they useno more fuel and power than is reasonable in thecircumstances. In order to demonstrate that theheating and hot water systems have beenadequately commissioned, regulation 20C states:

20C Commissioning

(A1) This regulation applies to building work inrelation to which paragraph F1(2) of Schedule 1imposes a requirement, but does not apply tothe provision or extension of any xed system formechanical ventilation or any associated controlswhere testing and adjustment is not possible.

(1) This regulation applies to building work inrelation to which paragraph L1(b) of Schedule 1imposes a requirement, but does not apply tothe provision or extension of any fixed buildingservice where testing and adjustment is notpossible or would not affect the energy efficiencyof that fixed building service.

(2) Where this regulation applies the personcarrying out the work shall, for the purpose ofensuring compliance with paragraph F1(2) orL1(b) of Schedule 1, give to the local authority anotice confirming that the fixed building services

have been commissioned in accordance with aprocedure approved by the Secretary of State.

(3) The notice shall be given to the local authority

a. not later than the date on which the noticerequired by regulation 15(4) is required to begiven; or

b. where that regulation does not apply, not morethan 30 days after completion of the work.


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4.31 Reasonable provision would be to preparea commissioning plan, identifying the systemsthat need to be tested and the tests that will becarried out. The notice required by regulation20C should confirm that the commissioning planhas been followed and that every system hasbeen inspected in an appropriate sequence andto a reasonable standard and that the test results

confirm that performance is reasonably inaccordance with the design requirements.

4.32 Not all ixed building services will need tobe commissioned. With some systems adjustmentis not possible as the only controls are on andoff switches. Examples of this would be somemechanical extraction systems or single fixedelectrical heaters. In other cases commissioningwould be possible but in the specific circumstanceswould have no effect on energy use.

Fixed building services which do not requirecommissioning should be identified in thecommissioning plan, along with the reasonfor not requiring commissioning.

4.33 Where commissioning is carried out itmust be done in accordance with a procedureapproved by the Secretary of State. For heatingand hot water systems the approved proceduresare set out in the Domestic Building ServicesCompliance Guide. For ventilation systems,an approved procedure would be to followthe guidance in the Domestic VentilationCompliance Guide14.

4.34 Commissioning is often carried out by theperson who installs the system. In other cases it

may be carried out by a subcontractor or by aspecialist firm. It is important that whoever carriesit out follows the relevant approved procedure indoing so.

4.35 Where a building notice or full plans havebeen given to a local authorityBCB, the notice ofcompletion of commissioning should be given tothatBCB within 5 days of the completion of thecommissioning work. In other cases, for examplewhere work is carried out by a person registeredwith a competent person scheme (see paragraphs3.19 to 3.22), it must be given within 30 days.

14 DomesticVentilationComplianceGuide,CLG,2010.

4.36 Where an approved inspector is theBCB,the notice of completion of commissioningshould generally be given to the approvedinspector within 5 days of the completion ofwork. However, where the work is carried outby a person registered with a competent personscheme (see paragraph 3.19 to 3.22), the noticemust be given within 30 days. Where the

installation of ixed building services whichrequire commissioning is carried out by aperson registered with a competent personscheme the notice of commissioning will begiven by that person.

4.37 Until theBCB receives the commissioningnotice it cannot be reasonably satisfied that Part Lhas been complied with and consequently isunlikely to be able to give a completion/finalcertificate.


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5.1 New thermal elements must comply withPart L1(a)(i) of Schedule 1 to the BuildingRegulations. Work on existing thermal elementsmust comply with regulation 4A of the BuildingRegulations which states:

4A.(1) Where a person intends to renovate athermal element, such work shall be carried outas is necessary to ensure that the whole thermalelement complies with the requirements ofparagraph L1(a)(i) of Schedule 1.

(2) Where a thermal element is replaced, the newthermal element shall comply with the requirementsof paragraph L1(a)(i) of Schedule 1.

THE PROVISION OF THERMAL

ELEMENTS

U-values5.2 U-values shall be calculated using themethods and conventions set out in BR 443.

5.3 Reasonable provision for newly constructedthermal elements such as those constructedas part of an extension would be to meet thestandards set out in Table 2.

5.4 Reasonable provision for those thermalelements constructed as replacements forexisting elements would be to meet the standardsset out in Table 2.

Table 2 Standards for new thermalelements

Element1 Standard (W/m2.K)

Wall 0.282

Pitched roof insulation at ceiling level 0.16

Pitched roof insulation at rafter level 0.18

Flat roof or roof with integral insulation 0.18

Floors3 0.224

Swimming pool basin 0.25

Notes:

1. Roof includes the roof parts of dormer windows, and wallincludes the wall parts (cheeks) of dormer windows.

2. Area-weighted average values.

3. A lesser provision may be appropriate where meeting such astandard would result in a reduction of more than 5% in theinternal floor area of the room bounded by the wall.

4. A lesser provision may be appropriate where meeting such a standardwould create significant problems in relation to adjoining floor levels.The U-value of the floor of an extension can be calculated using theexposed perimeter and floor area of the whole enlarged dwelling.

Continuity of insulation and

airtightness

5.5 The building fabric should be constructedso that there are no reasonably avoidable thermal

bridges in the insulation layers caused by gapswithin the various elements, at the joints betweenelements, and at the edges of elements suchas those around window and door openings.Reasonable provision should also be made toreduce unwanted air leakage through the newenvelope parts. The work should comply with allthe requirements of Schedule 1, but particularattention should be paid to Parts F and J.

5.6 A suitable approach to showing therequirement has been achieved would be toadopt Accredited Construction Details atwww.planningportal.gov.uk.

It is impractical to expect thermal bridge andtemperature factor calculations for work inexisting buildings.

RENOVATION OF THERMAL

ELEMENTS

5.7 For the purposes of this Approved Document,renovation of a thermal elementthrough:

a. the provision of a new layer means either ofthe following activities:

i. Cladding or rendering the external surface

of the thermal element; or

ii. Dry-lining the internal surface of athermal element.

b. the replacement of an existing layer meanseither of the following activities:

i. Stripping down the element to expose thebasic structural components (brick/blockwork, timber/metal frame, joists,rafters, etc.) and then rebuilding toachieve all the necessary performancerequirements. As discussed in paragraph3.9, particular considerations apply to

renovating elements of traditionalconstruction; or

ii. Replacing the water proof membrane ona flat roof.

5.8 Where a thermal elementis subject to arenovation through undertaking an activity listedin paragraph 5.7a or 5.7b, the performance of thewhole element should be improved to achieveor better the relevant U-value set out in column(b) of Table 3, provided the area to be renovatedis greater than 50 per cent of the surface of theindividual element or 25 per cent of the total

building envelope. When assessing this areaproportion, the area of the element should betaken as that of the individual element, not all theelements of that type in the building. The area of

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L1B GUIDANCE ON THERMAL ELEMENTS

the element should also be interpreted in thecontext of whether the element is beingrenovated from inside or outside, e.g. if removingall the plaster finish from the inside of a solidbrick wall, the area of the element is the area ofexternal wall in the room. If removing externalrender, it is the area of the elevation in which thatwall sits.

This means that if all the roofing on the flat roof ofan extension is being stripped down, the area ofthe element is the roof area of the extension, notthe total roof area of the dwelling. Similarly, if therear wall of a single-storey extension was beingre-rendered, it should be upgraded to the standardsof Table 3 column (b), even if it was less than50 per cent of the total area of the buildingelevation when viewed from the rear. If plaster isbeing removed from a bedroom wall, the relevantarea is the area of the external wall in the room,not the area of the external elevation whichcontains that wall section. This is because the

marginal cost of dry-lining with insulatedplasterboard rather than plain plasterboard is small.

5.9 If achievement of the relevant U-value setout in column (b) of Table 3 is not technically orfunctionally feasible or would not achieve asimple paybackof 15 years or less, the elementshould be upgraded to the best standard that istechnically and functionally feasible and whichcan be achieved within asimple paybackof nogreater than 15 years. Guidance on this approachis given in Appendix A.

5.10 When renovating thermal elements, thework should comply with all the requirements inSchedule 1, but particular attention should bepaid to Parts F and J.

RETAINED THERMAL ELEMENTS

5.11 Part L of Schedule 1 to the BuildingRegulations applies to retained thermalelements in the following circumstances:

a. where an existing thermal elementis part ofa building subject to a material change of use;

b. where an existing element is to become part ofthe thermal envelope where previously it wasnot, e.g. as part of a loft or garage conversionwhere the space is now to be heated.

5.12 Reasonable provision would be to upgradethose thermal elements whose U-value is worsethan the threshold value in column (a) of Table 3to achieve the U-values given in column (b) ofTable 3 provided this is technically, functionallyand economically feasible. A reasonable test ofeconomic feasibility is to achieve asimplepaybackof 15 years or less. Where the standardgiven in column (b) is not technically, functionally

or economically feasible, then the thermalelementshould be upgraded to the beststandard that is technically and functionallyfeasible and delivers asimple paybackperiod of15 years or less. Generally, this lesser standardshould not be worse than 0.7 W/m2.K.

Examples of where lesser provision than column(b) might apply are where the thickness of theadditional insulation might reduce usable floorarea of any room by more than 5 per cent orcreate difficulties with adjoining floor levels, orwhere the weight of the additional insulationmight not be supported by the existing structural

frame.5.13 When upgrading retained thermalelements, the work should comply with allthe requirements in Schedule 1, but particularattention should be paid to Parts F and J.

Table 3 Upgrading retained thermal elements

Element1 (a) Threshold U-value W/m2K (b) Improved U-value W/m2K

Wall cavity insulation2 0.70 0.55

Wall external or internal insulation3 0.70 0.30

Floor4,5 0.70 0.25

Pitched roof insulation at ceiling level 0.35 0.16

Pitched roof insulation between rafters6 0.35 0.18

Flat roof or roof with integral insulation7 0.35 0.18

1 Roof includes the roof parts of dormer windows and wall includes the wall parts (cheeks) of dormer windows.

2 This applies only in the case of a wall suitable for the installation of cavity insulation. Where this is not the case, it should be treated as wall external orinternal insulation.

3 A lesser provision may be appropriate where meeting such a standard would result in a reduction of more than 5% in the internal floor area of the roombounded by the wall.

4 The U-value of the floor of an extension can be calculated using the exposed perimeter and floor area of the whole enlarged building.

5 A lesser provision may be appropriate where meeting such a standard would create significant problems in relation to adjoining floor levels.

6 A lesser provision may be appropriate where meeting such a standard would create limitations on head room. In such cases, the depth of the insulationplus any required air gap should be at least to the depth of the rafters, and the thermal performance of the chosen insulant should be such as to achievethe best practicable U-value.

7 A lesser provision may be appropriate if there are particular problems associated with the load-bearing capacity of the frame or the upstand height.


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6.1 Regulation 17D of the Building Regulationsmay require additional work to be undertaken tomake an existing building more energy efficient

when certain types of building work are proposed.6.2 This requirement arises in existing buildingswith a total useful floor area of over 1,000 m2where the proposed work consists of:

a. an extension;

b. the initial provision of any ixed buildingservice (other than a renewable energygenerator);

c. an increase to the installed capacity of anyixed building service (other than arenewable energy generator);

6.3 Consequential improvements shouldonly be carried out to the extent that they aretechnically, functionally and economically feasible.

6.4 Only a relatively small number of existingdwellings will exceed 1,000 m2 in size. Where thereis doubt theBCB can be consulted for advice.

6.5 Technical guidance on achieving compliancewith regulation 17D is not given in this ApprovedDocument but where the regulation applies it isavailable in Approved Document L2B.

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7.1 On completion of the work, in accordancewith paragraph L1(c) of Schedule 1, the owner ofthe dwelling should be provided with sufficientinformation about the building, the ixed buildingservices and their operating and maintenancerequirements so that the dwelling can be operatedin such a manner as to use no more fuel andpower than is reasonable in the circumstances.This requirement applies only to the work thathas actually been carried out, e.g. if the workinvolves replacing windows, there is no obligationon the contractor to provide details on theoperation of the heating system.

7.2 Where the work involves the provision of anew heating system, a way of complying wouldbe to provide a suitable set of operating andmaintenance instructions aimed at achievingeconomy in the use of fuel and power in termsthat householders can understand in a durableformat that can be kept and referred to over theservice life of the system(s). The instructionsshould be directly related to the particularsystem(s) installed as part of the work that hasbeen carried out.

7.3 Without prejudice to the need to complywith health and safety requirements, anyinstructions should explain to the occupier of thedwelling how to operate the system(s) efficiently.This should include:

a. the making of adjustments to timing,temperature and flow control settings;

b. what routine maintenance is needed toenable operating efficiency to be maintainedat a reasonable level through the servicelive(s) of the system(s).

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Appendix A: Work to thermal elements

1 Where work involves therenovation of athermal element, an opportunity exists forcost-effective insulation improvements to beundertaken at marginal additional cost. Thisappendix provides guidance on the cost-effectiveness of insulation measures whenundertaking various types of work on athermal element.

2 Table A1 sets out the circumstances and thelevel of performance that would be consideredreasonable provision in ordinary circumstances.When dealing with existing dwellings someflexibility in the application of standards is necessaryto ensure that the context of each scheme canbe taken into account while securing, as far aspossible, the reasonable improvement. The finalcolumn in Table A1 provides guidance on anumber of specific issues that may need to beconsidered in determining an appropriate courseof action. As part of this flexible approach, it willbe necessary to take into account technical riskand practicality in relation to the dwelling underconsideration and the possible impacts on anyadjoining building. In general the proposed worksshould take account of:

a. the requirements of any other relevant partsof Schedule 1 to the Building Regulations;

b. the general guidance on technical risk relatingto insulation improvements contained inBR 26215;

c. for buildings falling within the categories setout in paragraphs 3.7 to 3.8, the guidanceproduced by English Heritage.

Where it is not reasonable in the context of theworks project to achieve the performance set outin Table A1 the level of performance achievedshould be as close to this as practically possible.

3 Table A1 incorporates, in outline form, examplesof construction that would achieve the proposedperformance, but designers are free to use anyappropriate construction that satisfies the energyperformance standard, so long as they do notcompromise performance with respect to any

other part of the Building Regulations.4 General guidance is available from suchsources as the Energy Saving Trust and relevantBritish Standards.

15 BR262Thermalinsulation:Avoidingrisks,BRE,2002.


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Table A1 Cost-effective U-value targets when undertaking renovation works to

thermal elements

Proposed works Target U-value(W/m2.K)

Typical construction Comments (reasonableness,practicability and cost- effectiveness)

Pitched roof constructions16

Renewal of roof covering No

living accommodation in the roofvoid existing insulation (if any) atceiling level. No existing insulation,existing insulation less than50 mm, in poor condition, and/or likely to be significantlydisturbed or removed as partof the planned work

0.16 Provide loft insulation

250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent

Assess condensation risk in roof space and

make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation. Additionalprovision may be required to provide accessto and insulation of services in the roof void

Renewal of roof covering Existinginsulation in good condition andwill not be significantly disturbedby proposed works. Existinginsulation thickness 50 mm or morebut less than 100 mm

0.16 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent. This may beboarded out

Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation. Additional provision maybe required to provide insulation and accessto services in the roof void

Where the loft is already boarded out and

the boarding is not to be removed as part ofthe work, the practicality of insulation workswould need to be considered

Renewal of the ceiling to cold loftspace. Existing insulation at ceilinglevel removed as part of the works

0.16 Provide loft insulation 250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent. This may beboarded out

Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation. Additionalprovision may be required to provide insulationand access to services in the roof void

Where the loft is already boarded out a