Readers are advised to check the validity of this Certificate by either referring to the BBA’s website (www.bbacerts.co.uk) or contactingthe BBA direct (Telephone Hotline 01923 665400).

1 The Building Regulations 2000 (as amended) (England and Wales)

The Secretary of State has agreed with the British Board of Agrémentthe requirements of the Building Regulations to which cavity closers andsub-frame fixing profiles can contribute in achieving compliance. In the

opinion of the BBA, the Cavalok Cavity Closure System, if used in accordancewith the provisions of this Certificate, will meet or contribute to meeting therelevant requirements.Requirement: C4 Resistance to weather and ground moisture

Comment: The product prevents the passage of moisture from the outerleaf to the inner leaf of a cavity wall at window openings.See sections 11.1 to 11.4 of this Certificate.

Requirement: L1 DwellingsRequirement: L2 Buildings other than dwellings

Comment: When the product is used as detailed in this Certificate,adequate provision will have been made to limit the thermalbridging which occurs around the opening of which it formsa part. The detail will therefore contribute to meeting therequirement of limiting the heat loss through the fabric of thebuilding and the risk of surface condensation on the revealwill be minimal. See section 10.1 of this Certificate.

Requirement: Regulation 7 Materials and workmanship

Comment: The product is acceptable. See section 15 of this Certificate.

Ravenscroft Plastics LimitedGreen LaneNewtownTewkesburyGloucestershire GL20 8HDTel: 01684 292272 Fax: 01684 299124e-mail: sales@cavalok.comwebsite: www.cavalok.com

AgrémentCertificate

No 00/3673Second issue*

Designated by Governmentto issue

European TechnicalApprovals

CAVALOK CAVITY CLOSURE SYSTEMPatronChablone

Product

Regulations• THIS CERTIFICATE RELATESTO THE CAVALOK CAVITYCLOSURE SYSTEM, A PVC-UCAVITY CLOSER ANDWINDOW ACCEPTOR USEDAS A TEMPLATE TO FORMAN OPENING IN MASONRYCAVITY WALLS DURINGCONSTRUCTION ANDSUBSEQUENTLY, INCONJUNCTION WITH ASTAINLESS STEEL CLIP, AS AFIXING FOR PVC-UWINDOWS.• The product closes the cavityat openings without forming athermal bridge and provides adamp-proof barrier betweeninner and outer wall leaves atthe point of closure.

CI/SfB

(31.4) Hn3

continued

2

In addition to the contribution which the product can make to meeting the relevantrequirements, the following comments should be noted:Requirement: A1 Loading

Comment: When used in conventional masonry cavity walls, the productwill transfer back to the structure wind and impact loadsimposed on the window. The walls require conventional tiesbetween the inner and outer leaves at window openings.

Requirement: B3(1) Internal fire spread (structure)

Comment: The product is acceptable. See sections 12.1 to 12.3 of thisCertificate.

2 The Building Standards (Scotland) Regulations 1990 (as amended)In the opinion of the BBA, the Cavalok Cavity Closure System, if used inaccordance with the provisions of this Certificate, will satisfy orcontribute to satisfying the various Regulations and related Technical

Standards as listed below.Regulation: 10 Fitness of materials and workmanshipStandard: B2.1 Selection and use of materials, fittings, and components, and workmanship

Comment: The product can contribute to a construction meeting thisStandard. See the Installation part of this Certificate.

Standard: B2.2 Selection and use of materials, fittings, and components, and workmanship

Comment: The product is an acceptable material. See section 15 of thisCertificate.

Regulation: 11 StructureStandard: C2.1 Stability

Comment: When used in masonry cavity walls, the product will transferback to the structure wind and impact loads imposed on thewindow. The walls require conventional ties between the innerand outer leaves at window openings.

Regulation: 12 Structural fire precautionsStandards: D2.1 and D2.2 Structural protection — PrinciplesStandards: D6.1 and D6.2 Concealed spaces — Principles

Comment: In conjunction with a cavity barrier, the product can satisfythese Standards. The product does not constitute a cavitybarrier. See sections 12.1 to 12.3 of this Certificate.

Regulation: 17 Resistance to moistureStandard: G3.1 Resistance to precipitation — Resistance to precipitation

Comment: Walls incorporating the product can comply with therequirements of this Standard. See sections 11.1 to 11.4 ofthis Certificate.

Regulation: 18 Resistance to condensationStandard: G4.1 Condensation — Interstitial condensation

Comment: The risk of damage due to interstitial condensation associatedwith the product will be minimal. See section 10.2 of thisCertificate.

Standard: G4.2 Condensation — Surface condensation

Comment: The risk of condensation on the inner surface of a revealcontaining the product will be minimal. See section 10.1 ofthis Certificate.

Regulation: 22 Conservation of fuel and powerStandard: J4.1 Buildings in purpose group 1 — Limiting thermal bridging at junctions and

around openingsStandard: J9.1 Buildings in purpose groups 2 to 7 — Limiting thermal bridging at junctions and

around openings

Comment: Walls incorporating the product can satisfy these Standards.See section 10.1 of this Certificate.

3 The Building Regulations (Northern Ireland) 2000In the opinion of the BBA, the position of the Cavalok Cavity Closure System,if used in accordance with the provisions of this Certificate, will satisfy orcontribute to satisfying the various Building Regulations listed below.

Regulation: B2 Fitness of materials and workmanship

Comment: The product is acceptable. See section 15 of this Certificate.Regulation: C4 Resistance to ground moisture and weather

Comment: Walls incorporating the product can contribute to meeting thisRegulation. See sections 11.1 to 11.4 of this Certificate.

Regulation: C5 Condensation

Comment: The risk of harmful effects on the building due to interstitialcondensation associated with the product will be minimal.See section 10.2 of this Certificate.

continued

• The product is for use inmasonry cavity walls withcavity widths of 50 mm and75 mm.• It is essential that the productis installed and used inaccordance with the conditionsset out in the Design Data andInstallation parts of thisCertificate.

Regulation: D1 Stability

Comment: When used in conventional masonry cavity walls, the productwill not adversely affect the structural stability of the walls. Useof the product does not obviate the need for conventional wallties between the inner and outer leaves at window openings.

Regulation: E4 Internal fire spread — StructureRegulation: E5 External fire spread

Comment: The product is acceptable. See sections 12.1 to 12.3 of thisCertificate.

Regulation: F2 Building fabric

Comment: When the product is used in an opening, adequate provisionwill have been made to limit the thermal bridging which occursaround the opening of which it forms a part. The detail cantherefore contribute to meeting the requirement to makereasonable provisions in the fabric of the building for theconservation of fuel and power. See section 10.1 of thisCertificate.

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4 Construction (Design and Management) Regulations 1994 (as amended)Construction (Design and Management) Regulations (Northern Ireland)1995 (as amended)

Information in this Certificate may assist the client, planning supervisor,designer and contractors to address their obligations under these Regulations.See section: 5 Description (5.10).

Technical Specification

5 Description5.1 The Cavalok Cavity Closer is a three-sided,U-shaped, PVC-U frame with a temporary timberhead brace (removed after installation) (see Figure 1).

Figure 1 Closer frame

5.2 The PVC-U sections of the frame are boxprofiles, sealed at the open end with a polystyreneplug (see Figure 2) and joined together either bywelding or mechanically, with a push-fitted cornerjoint (see Figure 1). Sections for use at the jamband, for externally-installed windows, at the sill,have an upstand against which the window frameis positioned (see Figures 3 and 6).

Figure 2 Typical closer section

5.3 PVC-U sections are available to suit 50 mmand 75 mm wide cavities and various applications(see Figure 3).

PVC-U section

polystyreneplug

Figure 3 Typical closer sections

internally-installed windows

externally-installed windows

upstand

jamb and sill

jamb sill

check reveal

jamb sill

4

5.4 Polypropylene ties are available from themanufacturer for fixing the frame into the surroundingmasonry, and stainless steel clips for securing theframe to the closer (see Figure 4).

5.5 A suitable double-sided glazing tape is usedto seal the joints between the window frame andcloser upstand (see Figure 6). However the tape isnot a part of the specified system and is outside thescope of this Certificate. Security glazing tapescovered by a BBA Agrément Certificate would besuitable.

5.6 The PVC-U closer sections are produced byconventional extrusion procedures. Quality controlchecks on the extrusion include heat ageing, heatreversion and dimensions.

Approved fabricators5.7 Approved fabricators assemble the closerframes to size.

5.8 Corner joints are made by mitring andwelding, or by cutting square and fitting with anABS injection moulded corner joint (see Figure 4).

5.9 The head is temporarily braced with a timberstrut, screwed to the closer upstand for externally-installed window applications (see Figure 1), andto a PVC-U angle (see Figure 4) fixed into the bodyof the closer for check reveal and internally-installedwindow applications. A suitable double-sidedglazing tape is applied by the fabricator to theface of the closer upstand which will be in contactwith the window frame.

Figure 4 Ancillary items

5.10 An approved fabricator is also responsiblefor preparing the window frame. This is constructedto allow 5 mm expansion all round with the sillattached in accordance with the manufacturer’srecommendations. Stainless steel clips are screwedto the jambs and sill of the window frame (up to100 mm from each end and at maximum 300 mmcentres). The clips are positioned against a stop ordatum line scribed on the frame, with the angledleg of the clip pointing out towards the direction

from which the window is to be installed (seeFigure 5). The clips must protrude a minimum 8 mmabove the level of the frame. If this is not possibledue to an excessive rebate depth, then packingstrips must be used. A plastic cover (see Figures 4and 5) is fitted over the sharp edges of the stainlesssteel clip as a safety measure prior to installation.

Figure 5 Window with clips

6 Delivery to site and storage6.1 Closer sections are transported to theapproved fabricator in shrink-wrapped bundles offifty 6 m lengths. Ancillary items are despatched inbags or boxes. The packs bear productidentification, a manufacturing reference and theBBA symbol incorporating the number of thisCertificate.

6.2 The closer frame and window frame withprotected clips fixed in position are despatchedto site from the fabricator as individual units, withthe fixing ties in bags. Care should be taken toensure that the clips protruding from the windowframe are suitably protected from damage duringtransit.

6.3 Closer and window frames should behandled with care and stored under cover in aclean area, and suitably supported to avoiddistortion or damage.

Design Data

7 General7.1 The Cavalok Cavity Closer is suitable for usein masonry walls with cavity widths of 50 mm and75 mm for fixing PVC-U windows.

7.2 The product provides an effective means ofclosing the cavity without forming a thermalbridge, and avoids the need for cutting bricksand blocks.

7.3 The product is suitable for use in flush-jamband check reveal applications, and canaccommodate externally- and internally-installedwindows.

7.4 The product can be used as a template, toform an opening around which a wall can beconstructed.

plastic clip cover clip

PVC-U angle(bracing connection)

tie

polystyrene end block

corner moulding

5

8 Practicability of installationInstallation of the product is straightforward andcan be carried out by tradesmen using traditionalskills, provided the installation instructions arefollowed.

9 Structural stability9.1 The Cavalok Cavity Closer must not be usedto support loads from the masonry. Lintels arerequired above window or door openings.

9.2 The product will not have an adverse effecton the structural stability of brickwork or blockworkwalls, constructed in the conventional manner inaccordance with normal good practice as definedin BS 5628-3 : 2001. Use of the cavity framedoes not obviate the need for conventional wallties around the openings.

9.3 PVC-U windows fixed to the closer framewith retaining clips, to the masonry or lintel at thehead, and, where necessary, to the inner leaf atthe sill (see sections 16 and 17), will satisfactorilytransfer to the structure the wind loads likely to beencountered in the UK. It is recommended thatwindow frames are reinforced, particularly those:• with side members over 1 m in length• used in exposed areas• with an opening light at the jamb.

9.4 For opening light windows there is a tendencyfor the frame to distort under the forces exerted bythe clips, when the window is opened. This isparticularly so for unreinforced window frames. Toprevent this distortion, additional screw fixing of theframe to the closer is recommended, as detailed inthe Certificate holder’s Cavalock TechnicalManual.

10 Hygrothermal behaviour10.1 Provided the closer and windowframes are installed in accordance withprovisions of this Certificate and, in

particular, that plasterboard minimum 13 mm thick,and window board, minimum 22 mm thick, arefixed on a minimum 5 mm plaster skim at thereveal and sill respectively, with the plaster skimfinishing at least 25 mm from the window frame(see Figure 6), then thermal bridging and the riskof local surface condensation around openingswill be acceptable, and meet the followingrequirements, where the window frame ispositioned against the closer upstand (see Figure 6)and thereby set-back 30 mm or more(1) into thewall cavity, and the junctions between the wallsand the front and back of the window/door frameincorporate an effective sealant.England and WalesApproved Document L1, Paragraphs 1.30 and 1.31Approved Document L2, Paragraphs 1.9 and 1.10

ScotlandTechnical Standards J4.1 and J9.1

Northern IrelandTechnical Booklet F, Paragraphs 1.33 and 1.34.(1) In determining the set-back position, the glazing tape istaken to be a part of the window frame.

Scotland and Northern Ireland10.2 Under normal domestic conditionsthe level of interstitial condensationassociated with the product will be low

and the risk of any resultant damage minimal.

11 Weather resistance11.1 The Cavalok Cavity Closer is effectiveas a vertical damp-proof barrier at jambs ofwindow openings in masonry constructions,

where a brick/block closer and dpc detail wouldnormally be used. The product is also effective as ahorizontal damp-proof barrier at the sill.

11.2 With externally-installed windows, theproduct is suitable for use in exposure categoriesup to at least ‘severe’, as defined in Table 11 ofBS 5628-3 : 2001 and depicted as exposurezones 1, 2 and 3 in the map shown in section 3.1of BRE Report BR 262 : 2002 Thermal Insulation:avoiding risks.

11.3 For windows installed internally into a flush-jamb detail, the product is suitable for use inexposure categories up to at least ‘severe’ asdescribed in section 11.2, subject to satisfactoryperformance of the glazing tape.

11.4 For very severe exposure conditions, asdefined in the Standard and Report (seesection 11.2), the use of the check reveal versionof the product is recommended. However,satisfactory performance in this application willdepend upon the performance of the glazing tapeand its silicone seal (see Figure 6).

12 Properties in relation to fire12.1 The Cavalok Cavity Closer will notcontribute significantly to the growth of a fire.On exposure to fire a surface char rapidly

forms and inhibits further combustion.

12.2 The product does not constitute a cavitybarrier against the penetration of smoke and flamein the context of the Building Regulations. This doesnot prevent its use in England and Wales orNorthern Ireland, where cavity barriers are notrequired around openings. In Scotland, however,the product is only suitable for use in conjunctionwith a cavity barrier meeting the performancerequirements defined in Technical Standard (D1.3),Table 1.

12.3 The use of the product does not preclude theneed to provide suitable fire protection to steellintels where this is necessary to satisfy the BuildingRegulations.

6

13 Security against intrusionRemoval of the window from outside is virtuallyimpossible as the retaining clips cannot bedisengaged from outside and the head is fixed tomasonry or a lintel.

14 MaintenanceTo ensure the maximum weathertightness, thesilicone seals to the external window joints must bechecked regularly and repairs or renewal carriedout promptly.

15 DurabilityThe product and accessories(1), protectedwithin the cavity, are assessed as durableand, when installed in accordance with this

Certificate, will not suffer degradation during thenormal expected life of a building.(1) Excluding the double-sided glazing tape (see section 5.5)— outside the scope of this Certificate.

Installation

16 General16.1 Installation of the product must be carried outin accordance with the manufacturer’s instructions.16.2 Reference should be made to the typicalinstallation details shown in Figure 6, whenreading the installation details given in section 17.Care needs to be taken to ensure that when the50 mm closer is used in externally-installedapplications it is positioned the correct way roundsuch that window/door frames are set-back by atleast 30 mm over the cavity.16.3 The clip fixing system has been approvedfor use only with PVC-U windows.16.4 The closer frame must be assembled by anapproved fabricator.16.5 The closer is selected to suit the application(see Figure 6), ie:• 50 mm or 75 mm cavity width• check reveal or flush jamb• internally- or externally-installed window.

16.6 The installation details required to meetthermal requirements (see section 10.1) must beobserved.

17 ProcedureCloser frame17.1 The cavity wall is built to the sill level.

17.2 The closer frame is placed correctly, in thesill cavity and propped vertically, with the box upagainst the outer leaf.

17.3 The box should be a tight fit in the cavity. Ifnot, it is recommended that, after installation, thecloser frame or window frame should be fixedback to the inner leaf at the sill with a rigid strapfixing or equivalent, particularly for installationsinvolving larger windows (above 1 m wide)and/or in exposed conditions.

17.4 Masonry is built up around the closer to lintelheight and fixed to the closer frame with ties, fittedinto the closer channel and embedded in alternatemortar courses of the outer brick leaf (every sixthcourse) and inner block leaf (every other course).

17.5 When the mortar has set, the timber bracingis removed from the closer frame and the lintelpositioned at the head ensuring that it is supportedonly by the masonry, ie the closer must not bearany weight.

PVC-U windows17.6 The protective plastic clips are removed fromthe stainless steel clips on the window frame.

17.7 The backing paper of the double-sidedglazing tape on the closer upstand is removedimmediately prior to installation.

17.8 The window frame is pushed centrally intothe opening ensuring that it locates against thecloser stop at jamb and sill and that all clipsengage.

17.9 Plastic packers are pushed under the frameat the sill.

17.10 The head of the frame is fixed back to themasonry or lintel.

17.11 Where necessary the window frame isfixed to the inner leaf at the sill (see section 17.3).

17.12 Where necessary, the frame of an openinglight is screwed to the closer (see section 9.4).

17.13 A silicone sealant is applied at appropriatepositions around the window frame (see Figure 6).

17.14 Plasterboard, at least 13 mm thick, andwindow board, at least 22 mm thick, are fixed ona minimum 5 mm plaster skim at the reveal and sill,respectively. In each case the plaster skim must finishat least 25 mm from the window frame (see Figure 6).

7

Figure 6 Installation details

externally-installed horizontal position (sill)

internally-installed horizontal position (sill)

check reveal horizontal position (sill) check reveal vertical position (jamb)

internally-installed vertical position (jamb)

externally-installed vertical position (jamb)

11

1

4 4

10 10

10

2 3

1 9 8

5

5

6 31 9

1 101 9 8

2 3 3

110

10

1 9 8

25

33

61

14

17 1

4

1 silicone sealant2 22 mm window board3 7 mm plaster skim set back at least

25 mm from the window frame

8 glazing packer9 foam strip

10 5 mm deep air space

4 glazing tape5 3 mm plaster skin6 13 mm plasterboard7 brick line flush with upstand

8

Technical Investigations

The following is a summary of the technicalinvestigations carried out on the Cavalok CavityClosure System.

18 Tests18.1 Tests were carried out on PVC-U extrusionsto determine:• shrinkage on heating

• gelation by immersion in acetone

• tensile impact, before and after heat ageing.

18.2 Tests were carried out in accordance withthe methods defined in MOAT No 1 : 1974, ona combined closer and PVC-U window, installedin a test rig, to determine:• air permeability

• effect of cyclic wind loads to ±1250 Pa

• effect of temperature variation (–5°C to 55°C)on resistance to wind loading

• resistance to wind loads of ±3000 Pa (Safetytest)

• resistance to wind gusting from 0 to 750 Pa.

19 Investigations19.1 An assessment was made of the hygrothermalproperties of constructions incorporating the product.In making this assessment, reference was made, asappropriate, to the ‘Robust Construction Details’(1)

BRE Report BR 262 : 2000 Thermal Insulation :avoiding risks and BRE Information PaperIP 12/94 Assessing condensation risk and heatloss at thermal bridges around openings.(1) Limiting thermal bridging and air leakage : Robustconstruction details for dwellings and similar buildingsTSO 2002.

19.2 A window installation was inspected toassess the practicability of the installation.

19.3 Factory visits were made to assess themanufacture and quality control of the extrudedprofiles.

19.4 An assessment was made of:• durability of all materials and components used

in the construction of the product• weathertightness of the product when installed in

accordance with the manufacturer’s instructions• fire resistance and structural stability of walls

incorporating the product

• weatherability of the exposed closer upstand inthe internally-installed window application.

9

Bibliography

BS 5628-3 : 2001 Code of practice for use ofmasonry — Materials and components, design andworkmanshipMOAT No 1 : 1974 Directive for the Assessmentof Windows

Conditions of Certification

20 Conditions20.1 This Certificate:(a) relates only to the product that is described,installed, used and maintained as set out in thisCertificate;(b) is granted only to the company, firm or personidentified on the front cover — no other company,firm or person may hold or claim any entitlement tothis Certificate;(c) has to be read, considered and used as awhole document — it may be misleading and willbe incomplete to be selective;(d) is copyright of the BBA.20.2 References in this Certificate to any Act ofParliament, Regulation made thereunder, Directiveor Regulation of the European Union, StatutoryInstrument, Code of Practice, British Standard,manufacturers’ instructions or similar publication,shall be construed as references to such publicationin the form in which it was current at the date ofthis Certificate.20.3 This Certificate will remain valid for anunlimited period provided that the product and themanufacture and/or fabricating process(es) thereof:

(a) are maintained at or above the levels whichhave been assessed and found to be satisfactoryby the BBA;(b) continue to be checked by the BBA or itsagents; and(c) are reviewed by the BBA as and when itconsiders appropriate.20.4 In granting this Certificate, the BBA makesno representation as to:(a) the presence or absence of any patent orsimilar rights subsisting in the product or any otherproduct;(b) the right of the Certificate holder to market,supply, install or maintain the product; and(c) the nature of individual installations of theproduct, including methods and workmanship.20.5 Any recommendations relating to the use orinstallation of this product which are contained orreferred to in this Certificate are the minimumstandards required to be met when the product isused. They do not purport in any way to restate therequirements of the Health & Safety at Work etcAct 1974, or of any other statutory, common lawor other duty which may exist at the date of thisCertificate or in the future; nor is conformity withsuch recommendations to be taken as satisfying therequirements of the 1974 Act or of any present orfuture statutory, common law or other duty of care.In granting this Certificate, the BBA does notaccept responsibility to any person or body for anyloss or damage, including personal injury, arisingas a direct or indirect result of the installation anduse of this product.

10

In the opinion of the British Board of Agrément, the Cavalok Cavity Closure System is fit for itsintended use provided it is installed, used and maintained as set out in this Certificate.Certificate No 00/3673 is accordingly awarded to Ravenscroft Plastics Limited.

On behalf of the British Board of Agrément

Date of Second issue: 19th December 2003 Chief Executive

*Original Certificate issued on 24th March 2000. This amended version includes modified PVC-U closer sections andclip, new statements in relation to Hygrothermal behaviour and Properties in relation to fire, amended national BuildingRegulations and CDM Regulations and a revised Bibliography.

11

BBllaannkk ppaaggee

British Board of AgrémentP O Box No 195, Bucknalls LaneGarston, Watford, Herts WD25 9BAFax: 01923 665301

©2003For technical or additional information,contact the Certificate holder (seefront page).For information about the AgrémentCertificate, including validity andscope, tel: Hotline 01923 665400,or check the BBA website.

e-mail: mail@bba.star.co.ukwebsite: www.bbacerts.co.uk