Joint Sealant

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T R E M C O S E A L A N T S O L U T I O N S

CONSTRUCTION SEALANTSA GUIDE TO THEIR SPECIFICATION & USE

January 2003

CI/SfB t4

CAW: Z22Uniclass: L675

Joint Design & Sealant Selection

Movement Considerations

Common Causes of Failure

Cladding Joints

Expansion Joints & Compression Joints

Window Perimeter & Curtain Walls

Window Perimeters

Trafficable Floor Joints

Roof Applications

Special Applications

Sealant Application Guideline

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PAGECONTENTS

INTRODUCTION

SEALANTSSPECIFICATION & USE

In modern buildings theperformance of the joints has evenmore significance than in traditionalbuildings, a result of the greaterdesign flexibility afforded by the useof new materials and constructiontechniques.

Joints and joint weatherproofingsystems require detailedconsideration to minimise the risk offailure, and the parameters for jointdesign and product selection needto be properly understood .The behaviour of joints in buildingshas been widely studied in recentyears and there is now considerableknowledge of the extent and rate ofmovement of a variety of material,components and their methods ofassembly.

The information contained hereinrepresents the view of TREMCObased on the collective experiencefrom the United Kingdom and fromother companies within theTREMCO Group world-wide.

In addition we refer you to twoBritish Standards publications:� BS 6093: Code of Practice for

the Design of Joints andJointing in BuildingConstruction.

� BS 6213: Guide to the Selectionof Construction Sealants.

� BS 8000 Part 16: 1997 -Workmanship on Building Sites

� ISO 11600

To meet the needs and criteria ofcontemporary building design,sealant compounds continue to beimproved. Product performancetargets have been set by TREMCOthat exceed industry standards toensure long term, weathertightjoints.

This manual is intended to offerpractical assistance to specifiersand users of sealants, in productselection and joint design to meetthe requirements of specific jointingsituations.

The details contained in this bookletare intended to help in the selectionand location of sealants and are notnecessarily accurate in otherrespects. For the sake of claritycertain details such as fixings maynot be shown. Whilst we makeevery effort to ensure the details inthis guide are accurate, werecommend that you contact one ofour TREMCO TechnicalRepresentatives to discuss yourexact requirements.

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Joint Design and Sealant Selectionare, of necessity, very closelyinterlinked, since the movement in,and dimensions of any joint, willhave a major influence on thechoice of sealant.

Joints can be broadly classified intotwo main categories. Those whichoccur because of discontinuityarising from assembly of individualcomponents - for example awindow frame into surroundingstructure and those which aredesigned specifically toaccommodate structuralmovement. For the purpose ofspecifying a sealant system theprincipal considerations areidentical.

CONSIDERATIONSFOR SPECIFYINGSEALANTSA number of factors need to betaken into account in determiningthe most suitable sealant.� EXTENT AND RATE OF

MOVEMENTThe total amount of movementwhich is expected to occur in ajoint will have a major influenceon product selection, and theway in which the movementoccurs also needs to beconsidered. Where rapidmovement occurs, such as inlightweight cladding materials,properties of elasticity in thesealant should be a high priority.In slow moving joints, sealantswhich exhibit stress relaxationproperties maybe moreappropriate.

� JOINT SIZESome sealants exhibit betterresistance than others to slumpand cold flow. Care needs to beexercised to ensure that onlysealants that can be installedinto joint widths within theirslump limits are specified.

� PRIMINGIn certain cases primers may berequired to ensure positive

adhesion of a sealant andadjoining substrate. It is vitalthat the correct primer isspecified and used at thecorrect coverage. Special oruncommon substrates shouldundergo a TREMCO laboratorytrial to prove adhesion andconfirm primer type.

� SUBSTRATEPREPARATIONCare should be taken to ensurethat joint substrates areprepared properly and thatacceptable minimums arestated within the specification.Substrates should be preparedin accordance with the sealantmanufacturersrecommendations, otherwisepremature joint failure will occur.Over 90% of all joint failuresresult from poor or inadequatepreparation.

Where one or both faces of thejoint have a weak or friablesurface, sealants with lowmodulus of elasticity arepreferred. Sealants with a highdegree of elastic recovery willimpose continuous stress on theinterface and are best avoidedwhere weak surfaces areencountered.

� CONDITIONS IN SERVICEThe environmental conditions towhich a sealant will besubjected will also affect itsperformance. This factor must,therefore, influence initialsealant selection. For example,temperature changes in buildingcomponents forming the jointare often far greater thanambient. This is especially trueof dark coloured materials whichabsorb radiated heat. Thesehigh temperature changescause greater joint movementand demand extra work fromthe sealant to meet both theannual and diurnal cycles.

Other situations demanddifferent properties in a sealant.

JO INT DES IGN & SELECT ION

Exposure to high humidity,chemical spillage, mechanicaldamage, permanentsubmersion, high U.V. , trafficuse, bio-degradation, colourstability are a few examples ofthe complexity of choice.Fortunately specialist advice,freely available from TREMCOTechnical Representatives, willguide the specifier in choosingthe most appropriate sealant.

� ECONOMICSChoose the sealant that is mostappropriate for the job. Thatmay not necessarily be the mostexpensive, nor the one with thehighest performance properties.

Usually, the higher theperformance properties, thehigher the level of preparationand workmanship required.Decide on the key propertiesthat are needed to allow thejoint to perform long term. Theymay be movement, chemicalresistance, aesthetics or acombination of factors - specifya sealant having those keyproperties and ignore the others.

Joint costs of material andlabour vary dramatically. Thematerial component usually bywastage and cross sectionalarea, and the labour componentby the effort expended per linearmetre.

Check the manufacturersrecommended maximum depthand pot life, together with thecontractors installationprocedures. These last twopoints alone will make avaluable contribution to keepingyour joint design competitiveand your client maintenancefree.

MOVEMENTCONSIDERATIONS

The designed joint will allow theamount of movement expected tooccur at the joint. Incorporate thechosen sealant to accommodatethat movement (MAF) and copewith construction tolerances oncomponent dimensions andinaccuracies that arise in fixing thecomponents.

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CALCULATION OFMOVEMENTMovement will occur as a result ofone or more of the following factors:

� THERMAL MOVEMENTAll materials change in size astemperature alters. Theamounts of change vary withdifferent materials, andtemperature changes affecting

components depend on theirlocation on the building and onheat gain/loss effects. Theamount by which thedimensions of materials willchange are calculated by usingtheir coefficients of expansion inthe expression:- Change =Length x Coefficient ofExpansion x TemperatureRange.

SERVICE TEMPERATURE RANGES (APPLICABLE IN UK)Part of Construction Maximum °C Minimum °C Range °C

Heavyweight Cladding - Light Colour 50 minus 20 70

Heavyweight Cladding - Dark Colour 65 minus 20 85

Lightweight Insulated Cladding - Light Colour 60 minus 25 85

Lightweight Insulated Cladding - Dark Colour 80 minus 25 105

Glass - Clear 40 minus 25 65

Glass - Coloured or Solar Control 90 minus 25 115

TABLE OF MOISTURE MOVEMENTMaterial Reversible Movement Irreversible Movement

% over 3 metres % over 3 metres

Limestone 0.01 0.3 mm

Sandstone 0.07 2.1 mm

Concrete (typical) 0.02 to 0.06 0.6 to 1.8 mm 0.03 to 0.08 (-) 0.9 to 2.4 mm (-)

G.R.C. 0.15 to 0.25 4.5 to 7.5 mm 0.07 (-) 2.l mm (-)

Clay Brickwork 0.02 0.6 mm 0.02 to 0.07 (+) 0.6 to 2.1 mm (+)

Calcium Silicate Brickwork 0.01 to 0.05 0.3 to 1.5 mm 0.01 to 0.04 (-) 0.3 to 1.2 mm (-)

Wood - tangential 0.6 to 4.0 10 to 120 mm

Wood - radial 0.4 to 2.5 12 to 75 mm

TABLE OF THERMAL MOVEMENTMaterial Coefficient of Thermal Movement over 3 metres

Expansion per °C 65°C range 85°C range 105°C range

Limestone 4 x 10-6 0.8 mm 1.0 mm 1.3 mm

Wood 4 to 6 x 10-6 0.8 to 1.2 mm 1.0 to 1.5 mm 1.3 to 1.9 mm

Clay Brick 5 to 8 x 10-6 1.0 to 1.6 mm 1.3 to 2.0 mm 1.6 to 2.5 mm

Granite 8 to l0 x 10-6 1.6 to 2.0 mm 2.0 to 2.6 mm 2.5 to 3.2 mm

Calcium Silicate Brick 8 to 14 x 10-6 1.6 to 2.7 mm 2.0 to 3.6 mm 2.5 to 4.4 mm

Glass 9 to 11 x 10-6 1.8 to 2. 1 mm 2.3 to 2.8 mm 2.8 to 3.5 mm

Concrete (typical) 12 x 10-6 2.3 mm 3.1 mm 3.8 mm

Carbon Steel 12 x 10-6 2.3 mm 3.1 mm 3.8 mm

Bronze 20 x 10-6 3.9 mm 5.1 mm 6.3 mm

G.R.C. 20 x 10-6 3.9 mm 5.1 mm 6.3 mm

Aluminium 24 x 10-6 4.7 mm 6.1 mm 7.6 mm

G.R.P. (polyester) 20 to 35 x 10-6 3.9 to 6.8 mm 5.1 to 8.9 mm 6.3 to 11.0 mm

PVC 40 to 70 x 10-6 7.8 to 13.7 mm 10.2 to 17.8 mm 12.6 to 22.0 mm

Polycarbonate 60 to 70 x 10-6 11.7 to 13.7 mm 15.3 to 17.8 mm 18.9 to 22.0 mm

Acrylic 50 to 90 x 10-6 9.8 to 17.6 mm 12.8 to 23.0 mm 15.8 to 28.3 mm

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� MOISTURE MOVEMENTMany materials which absorb orrelease moisture are subject todimensional changes as a resultof moisture movement. In thecase of some manufacturedproducts there may be someirreversible dimensional changesuntil their moisture contentsreach chemical equilibrium, aswell as the reversible changeswhich result from moisturemovement.

Cement based products shrinkand fired clay products expandas their moisture content tendstowards equilibrium.

In some materials the extent ofmoisture movement may varyaccording to the orientation ofthe structure (e.g. timber).

� OTHER MOVEMENTSIn some circumstances it maybe necessary to allow formovements resulting from loaddeformation or settlement.Exceptionally, joints may bedesigned to cater for seismiceffects.

MOVEMENTACCOMMODATIONFACTOR (MAF)The ability of sealants to acceptmovement without failure of thejoint system have been expressed indifferent ways by variousmanufacturers, but the acceptedmethod now becoming standard isto use the term MovementAccommodation Factor (MAF).

� MAF is defined as themaximum movement that thesealant is capable of toleratingthroughout its working life,expressed as a percentage ofthe joint width. (BritishStandards BS 6213 : 1982).

CALCULATION OFJOINT WIDTH (ButtJoint)

� MINIMUM JOINT WIDTHThis is simply determined fromknowledge of all the combinedmovements expected to occurat the joint, and of the MAF ofthe sealant. Movement in thecomponents resulting fromchanges in temperature andmoisture content can bedetermined by reference to thetables. Other movements shouldbe calculated by a structuralengineer. The minimum jointwidth is then calculated by:

where WS is minimum width, Mis total movement and F ismovement accommodationfactor.

� ALLOWANCE FOR TIMEOF SEALINGIt is unlikely that the climaticconditions expected whensealant installation will occur,will be known at design stage,and hence in the worst case,joints may be closed to theirminimum size in summer whensealant is applied. To allow forthis the equation for minimumjoint width is modified to:

� INDUCED DEVIATIONS(TOLERANCES)These occur as a result ofinaccuracies in manufactureand assembly of components.Wherever such deviations mightlead to a reduction of joint widththen allowance must be madein the joint design calculation tocompensate.

Increase of width by the totalamount of induced deviationsmay result in joints which aregenerally unnecessarily large,since the chance of the worstdeviations occurring at a singlejoint is very small.

In accordance with BS 6093allow for induced deviations byuse of the following equation:

Y = d1 + d

2 + d

3

where Y is the total allowanced1, d2, d3, etc., are the constituentdeviations. Then the designedjoint width becomes:

WD = W

S + Y

� WORKED EXAMPLE OFCALCULATION OF JOINTWIDTHThe example below assumes abutt joint with total movement of3 mm, and use of a sealant witha movement accommodationfactor of 25% . Tolerancesassociated with eachcomponent are ± 3 mm.

M = 3F = 25%Y = 9 + 9 = 18 = 4.24

� SEALANT GEOMETRYDifferent sealant types willrequire particular width to depthratios in order to give the bestperformance related to theirdynamic properties.Recommendations are given foreach individual sealant, but as ageneral guide sealants have apreferred width to depth ratio oftwo to one.

Regardless of this it is essentialthat the minimum sealant depthis always achieved (commonly 6mm) such that in narrow jointsthe width to depth ratio may beone to one (commonly up to12 mm).

Direction of Movement

BUTT JOINT

WS = ))) x 100MF

WS = )))))) + MM x 100 F

/

/ /

WD = )))))) + M + YM x 100 F

WD = )))))) +3+4=19 mm3 x 100 25


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JOINT DESIGN FORSHEAR (lap) JOINTS

Direction of Movement

SHEAR JOINT

Sealants operating in shear willallow more movement in the joint inview of the way in which theextension of the sealant occurs.Taking the movement relative tojoint width between the faces of thecomponents to which the sealantsadhere, then movementaccommodation figures may bedouble or better.

For example:� 25% MAF for butt joint ...

gives ... 75% in shear� 33a% MAF for butt joint ...

gives ... 85% in shear� 50% MAF for butt joint ...

gives ... 110% in shear

JOINT BACKINGTo achieve the correct sealantdepth, a backing material placed inthe joint will usually be necessary.Joint backing should becompressible, allowing unrestrictedjoint movement, and should notbond to the sealant.

The most suitable joint backing isclosed cell polyethylene foam,supplied in both round orrectangular sections, thencompressed 25% to 30% into thejoint pocket.

Joints constructed and formed withfibreboard or similar also requirejoint backing, prior to sealantapplication.

Use a bond breaker tape wherejoint depth is insufficient toaccommodate joint backing.

Joint backing is essential to:� Ensure correct sealant width to

depth ratio.� Provide firm support for tooling

to ensure positive contact withjoint faces.

� Prevent adhesion at the rearface.

JOINT BACKINGIN OPEN JOINT

JOINT BACKINGWITH FILLER BOARD

BOND BREAKERIN SHALLOW JOINT

TREMCO supplya full range of

materials- including joint

backing andsealant

applicationequipment

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COMMON CAUSESOF FAILUREThe failure of external joints isunsightly and leads to waterpenetration. This results in shortterm redecoration and long termstructural damage.

Common causes of failure are:� Incorrectly designed or formed

joint.

� Insufficient sealant applied.

� Excessive movement for thetype of sealant chosen.

� Sealant unsuitable for serviceconditions.

� Weakness in the substrate.

� Inadequate preparation.

� Incorrect or improperly usedjoint backing.

� Poor application technique.

� Poor workmanship: failure tofollow installation instructions.

COMMON CAUSES OF FA ILURE

Sealant applied without jointbacking will not obtain adhesion tothe joint faces.

Improperly sealed timber substratecan cause outgassing and blisters.

Failure due to weak substrate arris.

Joint backing punctured duringinsertion can cause outgassing andunsightly blisters in the sealant.

Sealant cohesion failure due to 3sided adhesion, excessivemovement or incorrect choice ofsealant.

Loose or undersized joint backingwill cause wrong sealant profilesand result in premature failure of thejoint.

Sealant adhesion failure due toincorrect preparation orincompatible sealant/substrate.


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CLADDINGJOINTS

PRECAST CONCRETETwo Stage Expansion Joint showingInterior Airseal and Exterior VentedRain Screen SealUse:� Dymonic NT/Dymeric**

� Proglaze 550

� Tremsil 500

� Tremflex 40

5mm Venting Tube

PRECAST CONCRETESingle Stage Expansion Jointshowing Rain Screen BaffleUse:� Dymonic NT/Dymeric**

� Proglaze 550

� Tremsil 500

� Tremflex 40

Closed Cell Joint Backing

Movement Joints between PrecastConcrete Cladding PanelsUse:� Dymonic NT/Dymeric**

� Proglaze 550

� Tremsil 500

� Tremflex 40

Expansion Joints in ExteriorCladdingUse:� Dymonic NT/Dymeric**

� Proglaze 550

� Tremsil 500

� Tremflex 40

For construction joints or lowmovement joints in cladding panels,use TREMCO Mono.** Dymeric is available from Tremco (Middle East) Limited.

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EXPANS ION JO INTS &COMPRES S ION JO INTS

Structural Expansion JointUse:� Dymonic NT/Dymeric**

� Proglaze 550*

� Tremflex 40

Movement Joint in BrickworkFacingsUse:� Dymonic NT/Dymeric**

� Proglaze 550*

� Tremflex 40

Compression Joint Concrete FrameBuilding with Brick FaçadeUse:� Mono

� Proglaze 550*

Compression Joint in StoneCladdingUse:� Dymonic NT/Dymeric**

� Proglaze 550*

� Tremflex 40

For low or moderate movement, useTREMCO Mono.


* TREMCO do not recommend the use of silicones in areas where staining orpigment migration may be aesthetically unacceptable.**Dymeric is available from Tremco (Middle East) Limited.


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WINDOW PER IMETER &CURTA IN WALLS

JAMB DETAILPlastic Frame to Concrete(PVCU, PVC, etc.)Use:� Tremfil (Interior Seal)

� Tremfoam (Bedding & Fixing)

� Tremflex or Tremsil 600 (ExteriorSeal)

JAMB DETAILAluminium to Rebated ConcreteOpeningUse:� Tremfil (Interior Seal)

� Proglaze 550, Tremflex orMono (Exterior Seal)

Typical Curtain Wall Mullion Detailwith Bond Breaker TapeUse:� Tremflex

� Proglaze 550

� Dymonic NT/Dymeric**

Typical Curtain Wall Mullion DetailUse:� Mono

� Proglaze 550

� Dymonic NT/Dymeric**

TREMCO Glazing TapeTREMCO Glazing Gasket

TREMCO Glazing Tape

INTERIOR

EXTERIOR

INTERIOR

EXTERIOR

**Dymeric is available from Tremco (Middle East) Limited.

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WINDOW PER IMETERS

HEAD DETAILTimber to Steel LintelUse:� Mono (Exterior Seal)

� Tremfil, Proglaze 550 orTremsil 600 (Interior Seal)

CILL DETAILAluminium to Timber Sub-frameUse:� Mono

JAMB DETAILTimber to BrickworkUse:� Tremfil (Interior Seal)

� Mono (Exterior Seal)

JAMB DETAILSteel in Timber - Sub-frame toBrickworkUse:� Tremfil (Interior Seal)

� Mono (Exterior Seal)


INTERIOR EXTERIOR

EXTERIOR EXTERIOR

INTERIOR

EXTERIOR EXTERIOR

EXTERIOR EXTERIOR

INTERIOR


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TRAFF ICABLE FLOOR JO INTS

Dowelled Trafficable ExpansionJointUse:� Tremflex 40/THC 900

Crack Control JointUse:� Tremflex 40/THC 900

Construction JointUse:� Tremflex 40/THC 900

Heavy Duty Floor Expansion Jointwith Metal Reinforced ArissesUse:� Tremflex 40/THC 900

Joint Backing

Crack Inducer

Separator tape where fibre board isbitumen impregnated

Joint Backing or Bond Breaker Tape

Separator tape where fibre board isbitumen impregnated

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ROOF APPL ICAT IONS

Precast Concrete Coping JointUse:� Mono

� Tremflex 40

� Proglaze 550

� Tremsil 500

Asphalt Tuck into RegletUse:� Tremcoveral

Expansion Joint in a Flat RoofUse:� Dymonic NT/Dymeric**

� Tremflex 40/THC 900



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SPECIAL APPL ICAT IONS

Fire Resistive Joint at Partition WallUse:� Dymonic NT/Dymeric**

Joint between Internal PartitionWalls, Doors, Frames and ScreensUse:� Tremfil

Gap FillingTypical pipe through brickworkUse:� Tremfoam

Wide Expansion JointUse:� Tremflex 40/THC 900

� Dymonic NT/Dymeric**(where non-trafficked)

Ceramic BlanketClosed Cell Joint Backing

Sand Filled Epoxy Nosing

Bond Breaker Tape

16 Gauge Metal Plate (fixed one end)

Bond Breaker Tape


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Perimeter pointing

Proglaze 550 l l l l l l l l l l l l l

Tremsil 100 l l l l l l l

Tremsil 200 l l l

Tremsil 250 l l l l l l

Tremsil 300 l l l

Tremsil 500 l l l l l l l l l l l

Tremsil 600 l l l

Tremstop 55 l

Mono l l l l l l

Tremfil l

Small Joint Sealant l

Tremstop 33 l

JS 800 l l l l

JS 770 l l

Tremflex 40 l l l l l

Dymonic NT/Dymeric l l l l l

Trembande l

Tremcoveral l

PU

Perimeter pointing

SILI

CO

NE

GL

AZ

ING

CO

NS

TR

UC

TIO

N

Sealing and bedding glass (doors/windows)

Compression glazing

Sloped glazing

Mitre/butt joints

Curtain walling

Cap bead

Heel/toe bead

General purpose sealant/caulking

Expansion joints

Construction joints

Compression joints

Cladding joints

Interior gap filler

Exterior gap filler

Fire rated expansion joints

S E A L A N T A P P L I C A T I O N SAC

RYL

ICB

UTY

LOT

HERS

abcTremco Limited (European Headquarters)

393 Edinburgh Avenue, Slough, Berkshire SL1 4UF UKTelephone: 01753 691696 Facsimile: 01753 822640

Website: www.tremcoeurope.comabcd

FM 01764

Tremco Limited - A company approved toBS EN ISO 9001:2000

‘TREMCO’, ‘TREMSIL’, ‘TREMFLEX’, ‘PROGLAZE’ and‘MONO’ are Registered Trademarks

PUBLISHED BY TREMCO, 2002 T3176/01

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