bqs 207 power point -week 1,2,3,4 introduction , windows, doors

7/26/2019 BQS 207 POWER POINT -Week 1,2,3,4 Introduction , Windows, Doors

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INTRODUCTION

Name : Mrs Olivia S. Otieno-Mwembe

Background: QS by profession Cum ConstructionProject Manager

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Course ObjectiveIntroduce students to technology of design and

construction of building f inishes and fixtures

Considerations of design, construction technique andmaterials functional, structural, thermal and acousticrequirement for these building elements;

Openings windows

Opening doors

Wall finishes Internal and external

Floor finishes

Ceiling finishes

Sheets and other rigid applied finishes

Paneling3

Course ObjectiveConsiderations of various materials used in finishes,

plaster, tiles, timber, sheets, paints, etc

Joinery fixtures in a simple domestic house wardrobes, built in cupboards, skirtings, corners,mouldings, etc

Drawing exercises of the various f inishes and fixturescovered in the course

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Course Importance

Student Quantity Surveyor ought to understand allaspects of building technology, this being one of them.

Finishes and fixtures form a big component ofbuildings, hence greatly affects costs; course will helpimprove the understanding of these aspects forpurposes of capturing proper costings.

Help to advice the clients on the best available optionsfor finishes and fixtures at affordable and reasonableprices.

Understanddesignchoices vs costconsiderations.

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ReferencesBarrys introduction to construction of buildings, by

Stephen Emmit and Christopher Gorse, 2005.

Barry, The construction of Buildings 2: Windows,Doors, Fires, Stairs, Finishes, 4th edition , 1992.

All building/construction technology books

Journals and magazines

Internet

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Schedule of ClassesWeek 1 Expectations & Introduction

Week 2 Windows

Week 3 Doors

Week 4 Wall finishes

Week 5 Floor finishes

Week 6 Ceiling finishes

Week 7 Joinery fixtures

Week 8 Continuous Assessment Test

Week 9 Rigid finishes

Week 10 Presentation of group projects

Week 11-12 Revisions and exercises

Week 14 15 - Exams7

Expectations

Examination will be as follows;Course Work = Sit in CAT (40 Marks) + Group Projects

(60 Marks)

The total for coursework is out of 100, will be convertedto 30% to get score for coursework.

Main examination = 70%

Failure to do both CAT and Group Project will lead to anautomatic fail, even if exams marks are available.

There will also be simple studio exercises in every lessonto improve the understanding of the technology behindthese building elements.

All drawings are as per class notes and constructiontechnology books

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IntroductionDefinitions;

Building finishes; This comprises those nonstructuralparts of the building. The finish is divided intoEXTERIOR finish (located principally on theoutside of the structure) and INTERIOR finish(located insideof buildings).

Finishing is important to cover up the rough surfaces ofconstructed walls, ceilings and floors. Good finishingwork result in smooth and aesthetically appealing

surfaces.Examples

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IntroductionOthermeanings of Finish;

To arrive at the end of; to bring to an end; to put an end to; to make an end of; to

terminate.

To bestow the last required labor upon; to complete; to bestow the utmost

possible labor upon; to perfect; to accomplish; to polish.

To come to an end;to terminate.

In respect to buildings, it may refer to the joiner work and other f iner work

required for the completion of a building, especially of the interior, and also

exterior.

Finishing work usually requires a lot of labour to give final and fair completion

to any these types of work; hence, minute detail, careful elaboration, are alwaysrequired.

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Introduction

Building fixture is any of the fittings or furniture of a

house, store, etc. attached to the building and,ordinarily, considered legally a part of it: exampleincludekitchen fittings, bathroomfixtures, etc.

Other examples

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A window is an opening formed in a wall or roofof abuilding to admit daylight through some transparent or

translucent material fixed in the opening.This means that its primary function is to provide a meansfor admission of natural daylight to the interior of thebuilding.

This primary function of a window is served by a sheet ofglass fixed in a frame in the windowopening.

A window can also serve as a means of providing thenecessary ventilation of dwellings, as required underbuilding regulations, by including into the window designopening lights.

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Windows, like doors can be made from a variety ofmaterialssuch as timber, metaland plastic.

They can also be designed in various ways by arranging thesashes to slide, pivot, or swing, or hang as a casement to oneof the frame members.

As the window is part of the wall or roof envelope, it shouldserve to exclude wind and rain, and act as a barrier toexcessive transfer of heat, sound and spread of fire in muchthesame way as the surrounding wall or roof does.

The functional material of a window, glass, is efficient inadmitting daylight and excluding wind and rain but is a poorbarrier to the transferof heat, sound and spreadof fire.

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The traditional window is designed to ventilate roomsthrough one or more parts that open to encourage anexchangeof air between inside and outside.

Ventilation is not a necessary function per se; since it canbe achieved openings in walls and roofs that are eitherseparate from the window or linked to perform theseparate function of ventilation.

The advantage of separating the functions of day lightingand ventilation is that windows may be made moreeffectively wind and weather tight and ventilation can bemoreaccuratelycontrolled.

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Functional requirements of a window;

The primary function of a window is;Admission of light,andthe secondary functions are;a view out,andventilation.

Day lighting is a necessary function and a view out isgenerally a desirable function. Ventilation is neither anecessary nor a desirable function yet it is traditionallyexpected of a window.

Aesthetics; the location of window in the faade of abuilding is also of importance to the appearance of thebuilding, since the style of the window used has a strong

influence on the architectural style of the building(fenestration).

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The functional requirements of a window as a componentpartof wall or roof are;

Structure strength and stability

Resistanceto weather

Durabilityand freedom from maintenance

Firesafety

Resistanceto the passage of heat

Resistanceto the passage of sound

SecurityCleaning

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Daylightthe prime function of a window is to admit adequatedaylight for efficient performanceof daytime activities.

Quantity of light admitted depends in general terms on thesize of the window or windows in relation to the size of theroom lit,and thedepth inside the roomto which useful light

will penetrate depends on theheight of the head of windowsabove floor level.

The shape, size and position of windows affect thedistributionof daylight in roomsand the view out.

Tall windows give a better penetration of light than lowwindows, separate windows give a less uniform distribution oflight than continuous windows, and windows in adjacent

walls give good penetration and reduce glare by lighting thearea of wall surrounding

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Windows in opposite walls of narrow rooms give goodpenetration and reduce glare by lighting opposite walls

aroundwindows.(Insert Fig 1).View out

As well as admitting daylight, it is generally accepted thatwindows perform the useful function of providing a view outof the buildings as a link with the outside and to provide the

variations of interest that stimulate and break the monotonyof repetitive tasks.

Studies have indicated that majority of people in sedentaryoccupations, such as office workers, derive benefit from a viewout.

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Sunlight

Majority prefer sunlight for a satisfying view, and also visualprivacy. Large windows enable people to mainly enjoy sunlightand a view.

In very cold countries, smaller windows are sometimespreferred to reduce heat loss and solar heat gain that can causediscomfort.

Glass, which is used in most windows is known to be a poorthermal and sound insulator, nonetheless, the subjectivepreference for sunlight and a view out, and the economicadvantage of freely available daylight and controlled solar heatgain, prompt the optimum use of glazing compatible withreasonablethermal and sound insulation.

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Ventilation

The current trend towards conservation of energy, by moreefficient use of insulation against excessive transfer of heat,

has led to the installation of double glazing to windows in bothnew and old buildings, and the fitting of effective weatherstripping around the opening parts of windows and doors toreduce draughts of cold air entering the building.

Open firs are also uncommon in modern buildings and manyopen fireplaces in older buildings have been sealed so blockingflue that provided some ventilation. This means that there isless provision for permanent changes of air, the air in roomsmay become stuffyand uncomfortable and at worstunhealthy.

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For their to be some provision of natural buildingventilation, the building code now requires means ofventilation to habitable rooms, kitchens, bathrooms, andsanitary accommodation to provide air change by natural ormechanical ventilation, and also to reduce condensation inrooms where warm, moisture vapour laden air may condense

water. The provisions are for opening windows and vents andsome mechanical ventilation to kitchens, bathrooms andsanitary accommodation.

For the comfort and well-being of people, it is necessary to

ventilate rooms by allowing a natural change of air betweeninsideand outside or to cause a change by mechanical means.

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The traditional method of ventilating is throughopening lights in windows. The advantage of openinglights is that they can be opened or closed to suit theindividual choice of the occupantof the room.

The disadvantage of opening the lights arethat they aredifficult to open just sufficient for ventilation withoutletting in cold air or gusts of wind; the necessary clearinggaps around opening lights may allow an excess of airleakage and rain leakage; the necessary framing around

them reduces the area available for glass; and theypresent a high security risk.

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For control of ventilation, the vertically sliding

window is the most eff icient as it can be operated toprovide either small gap ventilation between meetingrails and sashes and frame, or opened to nearly half itstotal area, and the degree of opening can be closelycontrolledbetween theseextremes.

Side hung casements are less efficient as they aredifficult to open to provide closely controlled gapventilation around three open edges of the sash and forthis reason top hung vent lightsare often used.

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Top hung lights are reasonably efficient but less readilycontrolled than the sliding sash in that there is likelihood

of both the extraction of air from below and the intake ofairfrom the sides.

Bottom hung windows will operate to enacourage theintakeof air over them and extraction from the sides.

Pivot windows are generally less efficient in control ofventilation as they are difficult to open sufficiently toprevent variable gusts of wind and cold draughts beingdirected in at low level. In addition, large pivot windows,when open, may be distorted by heavy gusts of wind, andmay then be difficult to close tight unless there ismechanismto lock sash shutat several points.

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Horizontally pivoted windowsshould be capable of beinglocked shut both at top and bottom else the top, opening inpart of the sash, may be forced in high winds and allow

considerableair seepage.Apart form the wish to fling windows open, there is everyreason to dispense with opening lights and replace themwith ventilators designed to control air movement only.These ventilators (also known as permanent ventilators),can be included in windows either in place of part of theglass or as part of the window head or cill construction, orthey may be fixed separatefrom the windows.(Insert fig 2)

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Strength and stability

A window should be strong enough when closed to resist thelikely pressures and suctions due to wind, and when open be

strong and stiff enough to resist the effect of strong winds onopening lights.

A window should also have sufficient strength and stiffnessagainst pressures and knocks due to normal use and appear tobe safe, particularlyto occupants in high buildings.

A window should be securely fixed in the wall opening forsecurity, weather tightness and the strength and stiffness givenby fixings.

Window choice and design should take into consideration thedirectionand strength of wind blowing

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Resistanceto weather

oAir permeability (air tightness)windows should be designed soas to conserve heat and avoid cold draughts. Air movementthrough closed windows may occur between the window frameand the surrounding wall, through cracks between glass and theframing, through glazing joints, and more particularly throughclearance gaps between opening lights and the window frame.

oLeakage of air around window frames, around glass and throughglazing joints can be avoided by care in design, construction andmaintenance.

oThe necessary clearance gaps around opening lights can bemade reasonably airtight by care in design and use of weather-stripping.

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oWater tightness penetration of rain through cracks and

around opening lights, frames or glass occurs when rain isdriven on to vertical windows by wind, so that the more the

window is exposed to driving rain the greater the likelihood ofrain penetration.

Due to smooth, impermeable surface of glass, driven rain willbe driven down, across and up the surface of glass thusmaking seals around glass and clearance gaps around openinglights vulnerableto rain penetration.

To minimize the penetration of driven rain through verticalwindows, it is advantageous to;

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1. Set face of window back form wall face so that projecting head and

jamb will give protection bydispersing rain.2. Ensure that external horizontal surfaces below openings are as few and

narrow as possible to avoid water being driven intothe gaps.

3. Ensure no open gaps around opening lights by use of lapped andrebated joints; also narrow joints that mayact as capillary paths.

4. Restrict air penetration by means of weather- stripping on the roomside of the windows so that pressure inside the joint is the same as thatoutside; a pressuredifferencewould drive water intojoint.

5. Ensure that any water entering the joints is drained to the outside ofthewindow by open drainagechannels that run to the outside.

6. Use weather stripping internally around opening lights toexclude windand reduce air filtration, and rebates and drain channels externally toexclude rain.

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Durability and freedom from maintenanceTraditionally, windows were made of softwood timber, and thesesuffered moistures movementwith change of moisture contentand may

rot where water opens open joints, if not well protected by paint orother protective coating.

A wood window strongly framed form sound, well seasoned woodprotected by a sufficiently elastic paint coating, that is adequatelymaintained, may have a useful life comparable to that of mostbuildings.

The disadvantage of softwood windows is that they require frequentmaintenance expenditure at intervals of f ive to ten years. It is these highcosts of maintenance of that have recently led to the large market inreplacementwindows of uPVCand aluminium.

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In the past,Steel windows were used and they acquired a bad namedue to the progressive, corrosive rusting that occurred with the use ofmild steel sections not protected with a galvanized zinc coating, whichthough used currently, also does not give a total protection againstcorrosion.They therefore need frequent painting.

Aluminium windowswhen exposed to air, formsan oxide that generallyprotects aluminium below it form further corrosion. This coating iscoarse textured, dull and silver grey and readily collects dust, is noteasily cleaned and has an unattractive appearance. For this reason,aluminium is coated by anodizing, polyester powder, organic or a cryliccoatings,to inhibit corrosion and appearance sake.

UPVC windows have been in use for many years, and they havemaintained their original characteristics over the period in variousclimatic conditions. Use of coloured uPVC bleaches with exposure toultra violet rays, hence white is usually recommended. Other thanoccasional washing, these windows need no maintenance.

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FiresafetyWindows should provide adequate means of escape in case of fire, limitinternal fire spread (linings & structure), limit external fire spread andprovideaccess and facilities for the fire service.

The windows put in place should not encourage spread of fire whensubjected to intense heat, and to be that which does give too much heatwhen burning.

Resistanceto passage of heatA Windows which is a component part of a wall or roof, affects thermalcomfort by transmission (passage) of heat, and through penetration ofradiant heat from the sun, that causessolar heatgain.

Glass which is the major part of the window, offers poor resistance to the

passage of heat and readily allows penetration of solar radiation. Glass haslow insulation and high transmittance value. Therefore, calculations can bedone to limit use of glass, but improve insulation and control transfer ofheator use of energy.

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Resistance to the passage of sound windows and doors prime source for entry of airborne sound boththrough glass, with afford little insulation through sound, and by cleargapsaround opening parts of windows and doors.

Reduction of this sound can be achieved by weather striping aroundopening partsof openings.

Transmission of sound through materials depend mainly on theirmass; the more dense the material the more effective it is in reducingsound.

The thin material, of a single sheet of glass provides poor insulationagainst airborne sound. A small increase in insulation or sound

reduction can be effected by use of thicker glass, or use of doubleglazing. (FigureFBT 184).

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SecurityWindows and doors are main routes for illegal entry into buildings. Burglary

may be carried out through; forcing open locks, bolts and catches, or removalor flimsily placed window hinges, removal of insecurely fixed window frames ,breakageof glass, or removal of a window pane to gainentry.

Some of these can be avoided by using wired glass which will retain wire evenif glass is broken, toughened glass which is hard to break compared to ordinaryglass, laminated glass is the best protection against burglary since it is noteeasily broken, but will not shatter but break into small pieces which have to beremoved for access. Double glazing also give the thief an extra sheet of glass tobreak.

All security measures will involve extra cost in better quality frames, sashes.Locks, bolts, hingesand glass.

Invest more in vulnerable windows, which can easily be broken into i.ehidden and rearwindows.

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Cleaning

To provide optimum light transmission and to enable

occupants to view the outside environment throughwindows, the glazing needs to be frequently cleaned.This is easy in small buildings since ladders can beused, but in taller buildings, it may be difficult andmoretechnical systemsemployed for cleaning.

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Insert Figure 3 - Traditional window showing parts (CT289)

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Materials used for windows windows are generallymanufactured from the following materials;

1. Timber/Wood

2. uPVC (plastic)

3. Aluminium

4. Steel

5. Bronze (notcommon)

Each of these materials have their advantages anddisadvantages.

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Timber/Wood

Traditionally, these were the most popular material forwindows, due to itsready availability,low cost,ease of workingby handor machine, had favourable strength to weight ratioand good appearance.

Because it is agood thermal insulator, there is little problemwith surface condensation on the frames of timber windows.

They are normally fixed into position by the builder as theexternal wall is constructed. The glazing is normally fitted intoposition with putty before building is made weather tight. Highperformance timber windows are generally delivered withsealed double glazing units already fitted.

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Disadvantages

Their high moisture movement, which can make casementdifficult to open or close in rainy seasons when the timber is

swollen. Any remedial treatment such as planing around edge ofcasement can increase gap between casement and frame whentimber shrinks in drier conditions. Increased gap may lead togreater amount of air infiltration and a reduced thermal andacoustic performance. However. Modern high performance onesare supplied double glazed and weather-stripped.

They are alsovulnerable to wet rotunless they are adequatelyprotected (by painting or staining every 3- 4 years). They canalso be clad in plastic or faced inaluminium.

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SteelSteel section windows have been in use for many years, but theirprogressive corrosion and rusting was a disadvantage until theintroduction of hot dip galvanizing protective coating, which nowmakes more durable.

Majority of steel sections ar emade form hot-rolled steel bars which isan expensive process from which limited range of scetions can beproducedeconomically.

Advantages

The slender sections for both frame and opening lights are possible toproducedue to their inherent strength and rigidity of the material.

The small sections provide optimum daylight admission, compared totimber.

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Disadvantages

High thermal conductivity that makes the window framing acts as a cold

bridge to the transfer of heat. This may lead to condensation which in turnaffects the internal wall finishes. This can be prevented by placing them in atimber sub-frame.

Due to their corrosive nature, they must be hot-dip galvanized, and beperiodicallypainted onceevery 4- 5 years.

theyare not as attractive as timber windows.

they require regular painting to protect them from rusting

They have narrow sections which do not readily accommodate doubleglazing.

Stainless steel windowsare also available but too expensive for consideration

in housing. It is however corrosion resistant, and can be used as a thincoating to timber and aluminium for its appearance and freedom formcorrosion. To keep its lustre, the stainless steel finish requires regularwashing.

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Aluminium windows

These are made from aluminium alloy to BS 4873 that is extruded in

channel and box sections with flanges and grooves for rebates andweather-stripping.

These thin walled channel and box sections give the material adequatestrengthand stiffness for use as window sections.

The material can be readily welded and has good resistance to corrosion.The aluminium alloy is resistant to corrosion that might cause loss ofstrength, yet the surface of the material fairly loses lustre owing to whitecorrosion products. The corrosive effect of the natural mill finish mightbe inhibited by anodising (creates a protective coating obtained fromelectronic oxidation) or liquid organic (produced by using acrylic orpolyester powder coating in a variety of colours) or clad in stainless steel.

All these finishes provide a high standard of durability and give them agood appearance.

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To maintain the initial lustre of the surface of these windows itis necessary to wash them at regular intervals.

Advantages

They have variety of sections available for the production of a

wide range of window types.

They are also free from destructive corrosion.

They have low maintenance requirements, hence low costs.

They also have a long lifespan.

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Disadvantages

They are generally more expensive than comparable wood orsteel windows.

High thermal conductivity of the material which acts as a coldbridge to heat transfer. To prevent this, they are constructed as atwo sections mechanically linked by plastic bridge that acts asthermal break. As an alternative, the inner face of aluminium iscovered with plastic, clip-on facing.

It is a relatively soft metal and window frames can easilybecome scratched or dented during construction process. Theyare therefore constructed at a later stage in the constructionsequence than is normally the case with timber or steel

windows.

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PlasticUPVC

The polymer, Polyvinyl-chloride (PVC) was first used in formingwindow sections in Germany during the middle of the twentiethcentury. the polymer in form of unplasticised (rigid) polyvinyl-chloride (uPVC) is softened by heating, extruded through a die andpressure formed to produce hollow box sections for window framesand sashes.

High impact uPCV include modifiers added to the constituentmaterial of uPVC to improve the impact resistance of the material

which is, by itself , readily subject to damage by slight knocks orabrasions.

They are much larger in size and therefore for the same area ofwindow have the least area of glazing of all the four materials

considered. Thus the amount of daylight admitted by these windowsis less than with theother framing materials.

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Advantages

It is maintenance free and maintain its smooth texturedsurface for the useful life of the material with occasional

washing to remove grime.

As the material is formed by extrusion it is practical to formvariety of rebates and grooves to accommodate draught seals.

The basic colour of the material is off-white which is colour-fast on exposure to ultra-violet light for the useful light of thematerial.

A range of coloured plastic can be produced either with thecolour integral to the whole of the material or as surface offinish.

They are durable and have low cost of maintenance.

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Disadvantages

Because uPVC has less strength and rigidity than metalsections, it is formed in comparatively bulky,hollow box sectionsthat are not well suited for use in small windows such ascasements.

The comparatively large coefficient of expansion andcontraction of the material with change of temperature and itspoor rigidity require the use of reinforcing metal sections fittedinto the hollow core of the sections to strengthen it and to anextentrestrain expansion and contraction.

They also had an initial consumer reluctance to accept themsince plastic had an association withcheap andshoddygoods.

They arequiteexpensive to purchase.

Can easily get damaged during construction.

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Fixed lights(or dead light), is used to describe the whole orpart of the window in which glass is fixed so that no part of theglazing can be opened. They aretypicallyof one sheet of glass.

Opening light an opening light is the whole or part of awindow that can be opened by being hinged or pivoted to theframe or which can slide open insidethe frame.

Windows with opening lights are classified according to themanner in which the opening lights are arranged to open insidethe frame.

Varioustypes illustrations (FTB pg 189)

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Illustrate (Figure 4 - Bar. Win.23)/(refer to FBT 189).

Hinged side hung , top hung, bottom hung

Pivotedhorizontallypivoted, vertically pivoted

Slidingvertically sliding, horizontallyslidingComposite actionside hung projected, top hung projected,bottom hung projected, sliding folding

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Fixing windows to ensure a good fit between thewindow frame and the wall it is preferable to buildwindows in as the construction progresses.

The frames may be secured to the wall by means ofgalvanised steel fixing cramps, or the frames may bescrewed to wooden or plastic plugs that have beeninserted into mortar joints of the wall. The vertical dpcthat is built into the gap between the frame and the wallsis then sealed with mastic.

Steel windows may be fixed directly to the wall reveals by

means of steel fixing lugs that are bolted to the back ofthe frame.

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Alternatively they may be screwed into timber orplastic plugs inserted into the wall. Steel window mayalso be fixed to a timber sub-frame, which has beenbuilt into the wall reveals.

Aluminium uPVC windows are normally fixed intoprepared openings, formed around a temporary timbertemplate. The windows may either be fixed into plugsinserted into the wall reveals or aluminium frames maybe fitted into a timber sub-frame in a similar manner tothat of steel windows.(insert fig 5 - draw figs FBT

195/6).

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Glass/Glazing

Glass is produced by fusing together silica, lime, magnesia,alumina and iron oxide at approximately 1500 - 1550. It isthen formed into sheets by a process of drawing, f loating orrolling.The commontypes of glass areclassifiedas below;

Annealed flat glasses

Processedflat glasses

Miscellaneousglasses

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a)Annealed flat glasses

1)Float or polished plate glassis transparent with surfacesthat are flat and parallel so that they provide clearundistorted vision and reflection.Float glass is made byrunning molten glass continuously on to a bed of moltentin on which the glass floats and flows until the surfaces areflat and parallel.Polished plate glass is made by grindingand polishing both surfaces of rough cast glass. These canbe modified to form, body tinted float/polished plate glass,surface modified tinted float glass, surface coated floatglass (reflective float glass).

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2) Sheet glass clear sheet (drawn sheet) glass istransparent glass manufactured by the flat drawn processin which a continuous sheet is drawn from a bath of

molten glass. Others are body tinted sheet glass and clearcast glass, body tinted cast and wired glass (cast with wirecompletelyembedded in it).

b) Processed flat glasses

1) Toughened (temperedglass)

2)Laminatedglass

3)safetyglass

4)Polycarbonatesheets

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c) Miscellaneous glasses Includes roof and pavement lenslights, copperlights, leaded lights and hollowglass blocks.

Fixing of glass - Glass may be held in position within its rebatesby means of glazing beads, putty or neoprene gaskets. Allopenings to receive glass should have a minimum rebate of 5mmand the glass should be cut 3mm shorter in length and breadththan the actual size of the opening.

Note: Please read more from your text books on glass and glazing.

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Window furniture; thereare two main ones

casement fastener security device to fix the casement intoits closed position. It is always operated by a hand-operatedblade fixed to the edge of the opening casement and locatingover a projecting wedge on a plate fixed to the mullion.Insertfig 6 - (FBT 198)

Casement stay this is a fixing device designed to hold thecasement in any number of desired opening positions. Itcomprises an arm with a series of locating holes and is fixed to

the cill member. A locating pin on a plate is fixed to the cillmember.

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Window cills - thissets the outside face of thewindows back

from theoutside face of the wall in which they are set so that

revealsof the opening give some protectionagainst driving

rain.They can be formed using tiles, bricks, stone, metal,

precast concrete, etc.(insert fig 7 -Bar.Win.66)

Window boardsthe internal surface to a window is covered

forappearance with a chosen material designed for the

purpose. The surface of the internal sillshould be such that it

can be keptclean. Can also be made of tiles, plastic, timber.(insert fig 8 - Bar.Win.68)

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Definitions

A dooris a solid barrier to a doorway or opening that can beopened for access and closed to deny access for privacy andsecurity, and serves as a thermal, acoustic and fire barrier aspartof an external wall.

A doorwayis an opening in a wall or partition , for access anda door frameor liningis the timber, metal, plastic frame orlining fixed in the door way or opening to which the doorcloseson hinges, pivots or runners.

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Functional requirements

Theprimary function of a door is; means of access, and thesecondary function is;privacy.

Means of access

A door opening should be sufficiently wide and high forreasonably comfortable access of people. In Kenya, thestandard size of a door is 900mm by 2100mm high, whichsometimes varies, both in width and height depending withthe function of a building.

The standard height makes allowance for all but the fewexceptionally tall people. For large rooms and spaces, a greater

width is often adopted for appearance. The standard width andheight has been chosen as convenient for the majority of thepeople.

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Double leaf doors are commonly used for access to grand, largespaces forappearance , and forconveniencein busy corridors.

The side on which the door is hung by hinges, its handing, andwhether it opens into or out of a room, are a matter of conveniencein use.

By convention, doors usually open into the room of which theyarepart of the enclosure.

Privacy

Doors should serve to maintain privacy inside rooms to the sameextent as the enclosing walls or partitions.

For visual privacy, doors should be as obscure as the walls orpartitions. For acoustic privacy, doors should offer the samereduction in sound as the surrounding walls, and be close fitting tothe door frame or lining, and be fitted with flexible air seals allround.

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The functional requirements for doors will be dependent onthe location of the door in the building. External doors havedifferent requirements to internal doors. The variousfunctional requirements of a door as a component part of a

wall or partition are;

Weather resistance

Structure strength and stability

Durability and freedom from maintenance

Fire safety

Resistance to the passage of heat (thermal insulation)

Resistance to the passage of sound

Security

Operation, the ability to be operated

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Weather resistance

External doors as part of the external envelop of thebuilding, and its associated frame should not allow rain or airinfiltration into the building. This can be difficult to achieve asthe door needs to be able to be opened and closed easily andthere therefore needs to be a sufficient gap between the doorand frame to allow this. This gap can be a potential point ofentry for rainwater and draughts into the building.

The design of the door and frame must therefore providefeatures that will overcome these potential problems aseffectively as possible.

The ability to retain the shape of the door when it issubjected to changes in climatic conditions is a major concern

with the timber doors.70

This shape stability seems to be better achieved on

heavier timberdoors than it is on their lighter counterparts.The addition of a metal foil vapour barrier behind thefacingsof f lushdoors helps to maintain shapestability.

Usually, for maximum water tightness on external doors,a door will need effective weather-stripping which will to anextent, make opening more difficult, and a high or complexthreshold which may obstruct ease of access

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Structurestrength and stability

Because doors are the main entry and exit points into a houseand to various rooms in the house, they need to be strongenough to resistonslaught by intruders.

Whether it be side hinged, top or bottom pivoted, or ontracks to slide and fold, a door must have adequate strength tosupport its own weight and suffer knocks and minor abuses inservice, as well as adequate shape stability for ease of openingand accuracy of closing to frameor lining.

Both strength and shape stability depend on the materialsfrom which a door is made and the manner in which thematerialsare framed as a door.

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Strength of doors is measured by four criteria; resistance totorsion, resistance to closing against obstruction, resistanceto impact with heavy body and resistance to impact with hardbody. It should also be resistant to vibrations and misuse ofdoorhandles.

Dimensional stability a door should not bow, twist ordeform in normal use to the extent that its appearance isunacceptableor it is difficult to open or close.

Hardwood door frames are stronger than softwood framessincethey have better resistance to splitting.

The type of locks, bolts and latches that are fixed to the dooralso influences the security of doors.

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Durability and freedom from maintenance

The material that the door and its associated frame aremanufactured from will affect their durability. In general,uPVC and aluminium doors will have longer life span than

timber doors but will also be more expensive to purchaseinitially.

Timber doors, although inexpensive to purchase initially,do require regular protection to be applied to them in theform of paint, stain or sealant. This maintenance cost needsto be added to the initial cost of the door and frame before atrue cost comparison can be made between timber doors andtheiraluminiumand uPVC equivalent.

This life cycle costing considers the total costs as well asthe initial purchase and installationcost of the product.

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Fire safety and resistance

Doors may serve two functions in the event of fire inbuildings, firstly as a barrier to limit spread of fire andsecondly toprotect escape routes.

To limit the spread of ire it is usual to divide largerbuildings into compartments of restricted f loor area bymeans of compartment floors and walls. Where doors areformed in compartment walls the door must, when closed,act as a barrier to fire in the same way as the walls. For thispurpose, doors must have a notional integrity, which is the

period in minutes that they will resist the penetration offire.

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There should be adequate means of escape formbuildings in case of fire, to a place of safety outside, which iscapableof being safely and effectively used at all times.

To meet this basic requirement it is usual to define escaperoutes from most buildings along corridors and stairways

which are protected by fire barriers and doors form theeffects of fire for defined periods.

This latter function of afire door is described as smokecontrol. The majority of doors along escape routes will needto serve as fire doors to resist spread of fire and to control

smoke.

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Resistanceto the passage of heat/thermal insulation

As doors form a part of the external fabric of the building,

they will affect the amount of heat that may be lost from thebuilding.

Doors do not have the same level of thermal perfomance asthe walls in which they are fitted. Doors that fit badly withintheir associated frames may suffer greater amounts of heat lossthan those that fit well.

Weather stripping to door frames reduced draughts causedby air infiltration through the gaps between door and its frameand also reduces heat loss through thesegaps.

As glass offers poor resistance to heat transfer, it is sensible tofit double glazing to reduce heat loss.

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Resistance to passage of sound/sound insulation

A door should afford reduction of sound for the sake ofprivacy and for those functions, such as lecture rooms, wherethe noise level is of importance.

As with thermal insulation, doors will have poorer acousticperfomance than the wall intowhich they are installed.

The heavier and more massive a door the more effective abarrier it is in reducing sound transmission.

A solid panel door is more effective than a flimsy hollow-core flush door. To be effective as a sound barrier, a doorshould be fitted with air seals all round as barrier againstairborne sound.

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Security

An external door, particularly at the rear or sides of buildings,out of sight, is obviously a prime target for forced entry.Glazing and thin panels of wood, brittle fiber glass and beadedplastic panels invite breakage with a view to opening bolts orlatches. Solid hinge locks and loose key bolts to solidify frameddoor in a soundly fixed solid frame are the best security againstforced entry.

Operation

A door should be easy to open, close, fasten or unfasten andshouldstay closed when shut.

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Traditional typeof door consistsone leaf, hinged on one side to a frame orlining, to open in one direction for the convenient entry and exit of people.Because of its simple construction, this type of door is used more oftenthanall the others. (Fig 1 - Bar.Drs.74)

Where a wide door opening is wanted for convenience or for appearance,

a side hung, double leaf, single swing doormay be used.(Bar.Drs.74)Where there is moderate to heavy traffic through doors, as along accesscorridors, Ii is usual tof itdouble swing doorseither on double swing hingesor floor springs, in the form of single or double leaf doors. As these doorsmay be pushed open from both sides simultaneously, it is usual for a toppanel to be glazed to avoid accidents.

Sliding doors are used either where there is limited space that hingeddoor would obstruct or for occasional access between rooms. Sliding doorsdo not afford the same ease and speed of access as a hinged door. Slidingdoors may be arranged as single ordouble leaf or three or more overlappingleaves (Bar.Drs.74)

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To convert two smaller rooms into one large room toaccommodate various activities, systems of hinged, slidingand sliding folding doors may be used. Centre fold doorsopen so that the leaves are folded back on the centre of theframe and edge fold into one or other side of the frames.(figure).

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They can also be categorised as external and internaldoors.

External doorsused to close the access to the interiors of abuilding and provide a measure of security. They need to be

weather resistant since in general they are exposed to theelements; this resistance is provided by thickness, stabilityand durability of the construction and materials usedtogetherwith protective coatings of paint and polish.

Internal doors these are used to close access throughinternal walls, partitions and to the inside of cupboards.General internal doors are thinner than their external

counterparts since weather protection is no longer arequirement.

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Wood/timber doors

These may be classified into four types by their methodof construction;

Panelled doors

Flush doors

Glazed doors

Fire doors

Match boarded doors

The traditional door is formed from solid softwood orhardwood members.

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Panelled doors may be of single or multiple panel construction,comprising a timber framework encasing panels of timber, plywood orglass, door leaves and frames. They are framed with stiles and rails around

a panel or panels of wood or plywood. The stiles and rails are cut fromtimbers of the same thickness.

This type of door is mostly used externally, therefore if plywood panelsare to be used, the plywood should be of external grade to provideadequate weather resistance.

The stiles and rails have to be joined to resist the tendency of the door tosink and the two types of joint used are a mortice and tenon joint and adowelled joint. (Fig 2/3 - Bar.Drs.77/76). Dowel joint is more popular, dueto its cheapness and ease of construction, which is particularly suited tofactory production lines. However, mortice and tenon joints tend to bestronger. Where dowelling is used, there should be three dowels to thebottom and lock rail, two dowels to the top rail and one on anyintermediate rails (Figure 4 - FBT 202).Where mortice and tenon jointsare used the middle and bottom rails should have double tenons.

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The panels are framed into grooves within framing stiles and rails and arecovered bymouldings that are scribedat their corners.

Water that runs down the face of the door is thrown clear at the bottomby a weather board, which is attached to the face of the door, preferably bya tongued and grooved joint. The weatherboard has a sloping face and isgroovedon its underside to prevent the underflow of water

Where glazing is used, any glazing beads should be positioned on theinsideof the door.

Figures Traditional panel door (Fig 5/6 - Bar.Drs.79/80), bevel raiseddoors (Fig 4 - FBT 202, Bar.Drs.80).

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Flush doorsTraditionally, flush doors have plain faces that are easy to clean anddecorate, being free of the mouldings that collect dirt. Some may havevery shallow sinking, to resemble appearance of panelled doors.

Flush doors may be faced with hardboard or plywood and maybemanufactured for internal or external use.

The shape and stability of these doors depends to an extent on thefixing of the flush or moulded facings to the core; the lighter andthinner the core the more the facings provide stability.

The method of construction for flush doors tends to be of threedistinct types, related to cost;

Cellular core

Semi-solid core

Solid core

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Cellular core f lush doorsThese doors are made with a cellular, fiberboard or paper core inalight softwood frame with lock and hinge blocks covered with plywoodor hardboard both sides.

These flimsy, light weight doors are for light duty such as internaldomestic doors.

They do not withstand rough usage, and they provide little acousticprivacy,thermal and sound insulation, fire resistance or security.

They are mass produced andthey are cheap.

It is also difficult to achieve flat surface to the facings at times due tothe limited support offered by core.

Figures Fig. 7/Fig 8 - Bar.Drs. 86/FBT 204

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Semi-solid core flush doorAlso known as skeleton-core flush door. This comprises an outer framewithin which smaller timber intermediate rails are spaced to provide aminimum of 50% timber in its construction, over which are then fixedthe facings of hardboard or plywood.

A skeleton core occupying 30% - 40% is a light duty core suitable forinternal domestic use, and one with sub-stantial intermediate rails of50% - 60%, is a medium duty door suitable for use internally in domesticand public buildings and for external use in sheltered positions.

The framing core members are joined with glued tongued and groovedjoints.

This door is still relatively light and inexpensive but the intermediate

rails do provide more support for the facings so that a f lat surface can beachieved more easily thanwith cellularcore door.

Fig. 7/8 - Bar.Drs.86/FBT 204

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Solid core flush doorThis door comprises a solid core of either block board, laminated board,chipboard, f laxboard or compressed fibre board strips, onto which areattached theply wood facings.

This door is of much heavier construction and consequently more expensivethan the skeleton core and semi-solid door types.

It also has good insulation properties, and some of them can be used as firedoors with integrity rating of 20 30 mins. ( Fig 8/ Fig 9 - FBT205/Bars.Drs.87).

Moulded panel doorsthese doors are of similar construction to f lush doors,but the facings are of hardboard that has been moulded under pressure toproduce a decorative appearance similar to that of a panelled door. However,although the door is similar in appearance to a panelled door, it does not havethesame construction as a panelled door.( Fig 8 - FBT 205).

Note: All flush doors and moulded panel doors may incorporate glazedpanels, secured by fixing beads. The facings of these doors tend to bevulnerable at their edges, so a thin strip of timber is fixed at the edges toprovide lipping.This also provides a tolerance for planing the doors to fit theframe or doorlining when the doorsare hung inposition. 89

Glazed doorsDoors with one or more glazed panel are used to give some daylight tospaces such as halls that have no windows, and to give some borrowedlight from a window through an internal door to an otherwise unlit space,hence the termborrowed light.

They are prepared with rebates for glass panels to be fixed with eitherbead or putty glazing. They can be single, double (two-panel)or multi-panelled glazed doors. Some ofitspanels may have glazing and others tohave ply or wood panel. (Fig 10 - Bar. Drs. 84/CT 266).

Purpose-made glazed doorsthese are constructed with diminishing orthin stiles to provide a greater width for glazing. Lower panels may be ofwood, with a large glazed panel above that may be glazed in one square ofglass or with several squares to glazing bars. The members of the timberdoor may be framed with mortice and tenon joints, with the glazing barsthrough-tenoned tostiles and rails. (Fig 11 - Bars.Drs.85)

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Fire doorsTo provide safe means of escape for the occupants of buildings in the earlystages of a fire, smoke control fire doors are fixed in enclosures to and alongescape routes.

To limit the spread of fire in buildings it is usual to divide all but smallbuildings into compartments surrounded by f loors and walls capable of

limiting the spread of fire for a stated period of minutes or hours.Door in compartment walls and doors to a protected escape route should becapable of resisting the spread of fire to the same extent that the enclosingwalls do.

Fire doors serve to protect escape routes and the contents and structure ofbuildings by limiting the spread of smoke and fire. Fire doors that are fixed forsmoke control only should be capable of withstanding smoke at ambient(surrounding ) temperatures and limited smoke at medium temperatures byself closing devices and f lexible seals. Those that are fixed to protect means ofescape routes should withstand smoke at ambient and limited smoke atmedium temperatures and have a minimum fire resistance, for integrity only,of 20 minutes (orso specified)

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A fire door should at once be easy to operate, serve as an effectivebarrier to the spread of smoke and fire when closed and be fitted withsomeeffective self closing device.

For ease of operation, there must be clearance gaps around the door

leaf. These clearance gaps are effectively sealed when a door leaf closesintoand up torebate in door frame.

As a barrier to the spread of smoke, flexible seals should be fixed todoor leafs of frames and as a barrier to the spread of fire heat activated(intumescent) sealsshould be fitted.

Fora fire door to be effective against the spread of smoke and fire, thedoor leaf should, when not in use, be positively closed to the frame bysome self closing device. The conventional door closers are used,overhead closers (fig 12 - Bars.Drs. 88) and floor closers (Fig 12 a -Bar.Drs.83).

Figure for fire doorFBT 207,Other examples (Bar.Drs. 116, showingdifferent facings.

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Match boarded doorsThese are made with a facing of tongued, grooved and v-jointed boardsfixed vertically to either ledges and braces or a frame. They are used forcellars, sheds and stores where the appearance of the door is notconsidered important. There are three specific types namely;

Ledged

Ledged and braced

Framed, ledged and braces

Ledged match boarded door

The face of this door is constructed from approved tongued and groovedboarding, calledbattens,with edge chamfers to form a V joint feature

between consecutiveboards

The battens are clamped together to form a panel and are attached bynailing to approved horizontal timbers, called ledges,positioned in themiddle of the doorpanel and also, from itstop and bottom edges.

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The nailing of the boards to the ledges does not strongly frame thedoor which is liable to sink and lose shape. This door is inexpensive toconstruct but there is a tendency, over time to, for the door to drop outof shape.

This door is used for narrow openings only. (Figure 14 - FigureBars.Drs. 90).

Ledged and braced door

This type of door is strengthened against sinking with braces betweenthe rails that are fixed at an angle to resist sinking on the lock edge. Thebraces are nailed to the boarding, and can also be fixed using morticeand tenon joints.

To further resist the tendency for the door to drop out of square, threehinges, rather than two are fixed to the edges on the hanging side of thedoor.

Figure 15FBT 208,

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Framed, braced and ledged match boarded doorsAdded strength and rigidity can be provided to the door by enclosing

the panel in a mortice and tenoned frame comprising top, bottom ,middle rails,stiles and braces.

The boarding runs from the underside of the top rail, to protect the endgrain of the boards from rain, down over both middle and bottom rails.

To allow for the boards running over them the middle and bottom railsare less thick than the stiles to which they are joined with a barefacedtenon joint.

These doors are rarely now used for internal or external doors on housesbut arestill specified forout buildingsand garages

The framed, braced and ledged is commonly used for large openingssuch as garage, factories and entrance gates. This is because their frameconstruction makes them stronger than the others.

Figure Bars.Drs.90.

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Aluminium doorsThese are constructed of same material as windows. The doors

normally comprise top, middle and bottom rails and stiles of extrudedaluminiumalloy sections enclosingglazed panels.

The slender sections possible with the material in framing the doorsprovide the maximum area forglass.

These glazed doors can be made as both singl e-and multi-leaf doors tohinge, slideor slideand fold to open.

The finishes to the doors are similar to those available for aluminiumwindows. The doors can also be fitted into hardwood frames suppliedseparately.

The particular use forthese doors is to provide a large area of clear glassfor an unobstructed view out to gardens and to give ready access frominsideto outside.

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A disadvantage of these doors is that there may be condensation on theinside faces of the aluminium framing. To minimise condensation, it ispractice to fabricate them as thermal break doors. The main framingsections of the doors, which are jointed with corner cleats, are fixed to

aluminiumfacings through plasticsections that act as thermal break. The traditional aluminium doors may be a poor security risk unless thepanels are reinforced with aluminium sheet in the core and the panels arefixedwith screwed or secured beads.

An advantage of these doors is that they may be f inished in a range ofcoloured powder or liquid coatings that donot require periodic painting formaintenance. The doors are sufficiently robust for use in domesticbuildings and may befabricated as thermal break construction to minimisecondensationon the internal faces of thealuminium framing.

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UPVC doorsSimilar to aluminium doors, uPVC doors are constructed from rigid uPVCextrusionsin a similar manner to uPVC windows.

Large doors may require these extrusions to be stiffened with steel sectionsinserted into the hollowcores, mitred and heat fusion welded at corners.

These doors comprise top, intermediate, middle and bottomrails and stilesof extruded uPVC sections enclosing uPVC panels and glazing according todesign.

The uPVC door leafs are framed for glazing with single or double glazing ,secured with internal pop-in beads and weathered with wedge and bladebaskets.

As an alternative to glazed panels a variety of plastic panels is producedfrom press moulded acrylic, generally moulded to imitate wood door panels

either as fulldoor height panelsor as two panels fitted to a middle rail.They are generally supplied in white or off white, but other colours areavailable, including timber effect. This is to minimise the considerablethermal expansion that this material suffers due to solarradiation.

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The doors are fitted into uPVC frames supplied with the doors. Colouredand wood grain finishes are alsoavailable.

The advantage of the uPVC door is that they require no maintenance

duringtheir useful life, other than occasional washing.The disadvantage of these doors is that they may jam shut due tothermalexpansion, knocks and indentations cannot disguise by painting, and theyarenot as robust to heavy use as a traditional wood framed door.

Steel doors

Glazed steel doors- These are fabricated from the hot rolled steel sectionsused for windows. The sections are assembled with welded corner joints.The doors and frames, which are hot dipped galvanized after manufacture,may be finished with an organic powder coating. Single glass is eitherputty or clip onaluminium bead glazed. Glazed steel doors, which havelargely been superseded by aluminium doors, are mainly used forreplacement work.

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Flush steel doors these are manufactured from sheet steel which ispressed to shape, often with lipped edges, hot dip galvanized or eitherseam welded or joined with plastic, thermal break seals around a fiberboard, chip board or foamed insulation core, generally with edge, wood

inserts as framing and to facilitatefixing of hardware.The sheet steel facings may be flush faced or pressed to imitate woodpaneling or glazed panels. The exposed faces of doors may be finishedready forpainting or with a stoved or organic powder or liquidcoating.

These comparatively expensive, robust, heavy duty doors are generallyused in commercial and industrial buildings, and also as fire doors.They are supplied as door sets complete with frame, door leaf ,hardwareand fittings.

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Door framesthis is a surround in a door way or opening, to which thedoor is hung and to which it closes, which has sufficient strength initself to support theweight of the door.

It consist so mainly four members head, a pair of vertical jambs,threshold or cill, joined together by doweled mortice and tenon joints or

combed joints.Mainly used on external doors and heavy doors.

To prevent the ingress of water beneath external doors, a galvanizedmild steel waterbar can be placed within the threshold of the frame anda rebate is cut in the bottom rail of the door to ensure a tight fit againstwater bar. The top surface of the threshold to the exterior of the waterbar is sloped to allow water to be conducted away form the opening. Theunderside of the threshold is throated to prevent water from runningunderneath. (FBT 209).

The frames may be built in to the wall reveals, as the wall is beingconstructed, by means of galvanized mild steel fixing cramps, as thatused in windows.

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Door liningsis a surround inside a doorway oropening, as wide as thereveal, to which the door is hung and closes, which is not in itself strongenough to support the weight of the door without support form thesurroundingwall or partition.

These are never built in, but are fixed into a prepared opening by fixingthem directly to the reveals. The gap between the door lining and thereveals is covered by an architrave.

Mainlyused for internal doors.

Both frames and lining may be made from wood, metal or plastic.Frame is a solid rectangular section and the lining a thin section as wideas the wall or partition and plaster which it covers or lines. Figureillustrating difference between door frame and lining (Bar.Drs.91)

Note: Read more on the various door frames and their designs fromtechnology books.

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Door sets (door assemblies)These are combinations of doors with door frames or linings andhardware such as hinges and furniture, prepared as package ready for useon site. This plainly makes sense where many similar doors are to be usedand packets of doors can be ordered and delivered instead of separatelyordering doors, frames and hardware.

These door sets have the door fixed to the frame using rising butthinges,so that the door can be taken out of the frame prior to the framebeing fitted into the wall and then lifted back into position when thefinishes to the wall have been completed. Because the door is delivered tosite fitted in its frame, there is no need for subsequent planing of thedoorto fit intothe frame when the door is finallyinstalled. (FBT 211).

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Hardware for doorsthese are a wide variety of items that canbe fixed to the door for operational, security or durabilitypurposes. Ironmongery was a term used when most of theseitems were made of iron or steel. It is the general term used toreferto;

Hinges

Latches

Locks

bolts

Letterplates

Finger and kicker plates

Self closing devices

Read moreon these and write short notes, with illustrations.

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bqs 207 power point -week 1,2,3,4 introduction , windows, doors

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