British Urethane FoamContractors Association

PO Box 12, Haslemere, Surrey, GU27 3AH Tel/fax: (01428) 654011 email: info@bufca.co.ukwww.bufca.co.uk

British Urethane Foam Contractors AssociationP O Box 12, Haslemere, Surrey GU27 3AH

Tel: 01428 870150E-mail: info@bufca.co.ukwww.bufca.co.uk

of Practice for Control of Condensation inBuildings. Surface and interstitialcondensation on all building surfaces caneasily be prevented. The ultimate pitched roof design is 100mmPU foam or fibre at ceiling joist level,unventilated loft space and 100mm of foamat rafter level to provide the perfect balancebetween optimum thermal performance andzero condensation risk. This constructionretains the storage usage of the loft space,negates the requirement for insulation topipes and tanks and installed roof ventilationsystems and achieves a U-value of betterthan 0.13W/m2K.

A quieter home Spray-applied foams unique sealing qualitiesalso have a significant effect on reducingairborne sound penetrating the property. It isalso ideal for soundproofing interior wallsand floors in conjunction with approveddesigns and around plumbing stacks toreduce the sound of water rush. Open cellpolyurethane foams are also entering themarketplace with enhanced soundattenuation properties.

WallsSpray-applied foam may be applied directlyonto solid wall surfaces to give an insulated,damp resistant covering which eliminates theproblems of rain penetration and risingdamp. The foam can be plastered with abonding plaster to give a rustic finish orplasterboard applied by using plaster dabs.Alternatively, it can be applied in between

The British Urethane Foam Contractors Association(BUFCA) provides a professional forum for its membersamongst whom are the top experts in polyurethanetechnology today. It also provides links to government,research laboratories and associated bodies.

The objectives of BUFCA are to ensure the highest standards of Quality andService from our members and to provide you, the specifier, with authoritativetechnical advice in all aspects of design and application. All enquiries we receiveare directed to relevant expert BUFCA members, which include those at theforefront of ecological polyurethane technology.

SAP 2005‘U’ ValueW/m2k

TypicalFoamDepthmm

TypicalFoamDepthmm

20% belowSAP 2005‘U’ ValueW/m2k

Element

Room in Roof (New Build) 0.20 120 0.16 150

Pitched Roofs 0.16 85* 0.13 100*

Flat Roofs 0.25 85 0.20 110

Walls 0.35 60 0.27 75

Floors 0.25 50 0.20 60

* Calculation based on unventilated loft space with 100mm mineral fibre at ceiling level.

2

New buildMeeting building regulations- Part LSprayed and injected polyurethane foamsystems provide an ideal way of achievingvery high insulation standards whilstproviding effective controls against unwantedair leakage and preventing condensation. Theinsulation value is amongst the bestavailable as the foam seals all gaps andmoulds itself to all contours. It has the abilityto provide significant structural strength andit creates its own vapour control layer – soessential in today’s highly insulated buildings.Spray applied polyurethane foams are for use in:(a) timber frame walls,(b) pitched and flat timber roof constructions(c) timber and concrete ground-floor

constructions

Condensation control& air leakageSpray-applied polyurethane foams (PU foam)meet the Building Regulations in respect ofcondensation control by compliance with theApproved Document F 'Alternative Approach'for non-ventilated roofs. Calculations aremade using the method in BSEN ISO13788:2002 (and BS 5250 Appendix D): Code

timber frame studwork, sealing all gaps, andthen be covered over conventionally withplasterboard. Sloping ceilings, which oftengive rise to difficulties in achievingacceptable U-values, are easily insulated tohigh warm deck specifications.

Better air quality There are no noxious or odious fumes orvapours in the cured form. Spray-appliedfoam is especially recommended for thosesuffering from allergies, asthma, or otherrespiratory problems. It contains noformaldehyde and has no detectableemissions once cured. It contains no fibresand does not shrink, sag, settle, slip or turnto dust. It offers no food value to bacteria,fungus, insects or vermin. Humidity andcondensation are better controlled so thatthe health concerns with regard to mould ormildew are relieved.

Stabilisation andinsulation of existingdwellings Spray-applied foam is applied to theunderside of the roof which bonds slates andtiles to each other and to structural orsupporting timbers to replace the anchorageof fixing nails. It is a much less costlyalternative to re-roofing and can be appliedto slates, tiles, pantiles, and other variousroof coverings. It permanently cures theproblems of nail fatigue and makes the roofmuch more resistant to storm or impactdamage. Because it is liquid when it isapplied, it seeks and seals any unwanted airleakage that may occur preventing theingress of wind-driven rain, snow and dustand dramatically reducing heat loss. By installing the insulation at rafter level itkeeps the loft void warmer and preventscondensation build-up which can otherwiseoccur when increasing insulation at ceiling

level. The warmer, drier, cleaner roof spaceeliminates the risk of pipes and tanksfreezing. The water vapour resistance of thespray applied foam is sufficient to preventinterstitial condensation but allows thebattens, which are covered on three sides bythe foam, to 'breathe' and by preventingwind-blown rain and snow the battens staydry. The spray applied foam used in loftsmeets Class 1 Surface Spread of Flame whentested to BS 476 Part 7: 1997. The foam also slows the deterioration oftile/slates by frost. On the underside of thecovering frost damage is eliminated. On theweather side the frequency of thefreezing/thawing cycle is reduced. Slates andtiles will be less prone to damage by impactas the foam distributes the forces. Whereslates and tiles are damaged afterinstallation, they may be replaced by cuttingaway the foam from the underside, replacingthe slate or tile and re-treating the affectedarea. Aerosol cans are suitable for small areas. Test data confirm that although the sprayapplied foam adds only 2kg/m2 total weightto the roof, treated roofs have sufficientcohesive and compressive strength to

3

BreatherMembrane

Unventilated Air-space

Foil-faced Plasterboard

125mm PU Foam

150 x 50mmRafter

Sloping Ceilings/New Build - 0.16Wm2k

Spray-applied polyurethane foamslows frost damage to slates andtiles and saves energy

Installing the insulation at rafterlevel keeps the loft void warmerand prevents condensation build-up

transfer the loads imposed by the roofcovering should the battens be deficient.Spray applied foam contains no nutritionalbenefit and is not attractive to vermin orpests and closes off common access routes.Tiles and slates adhered in place preventtheft. It has been found to be particularlysuitable for historic and listed buildingswhere it is important to maintain the originalcharacter of the roof.

Barn conversionsSpray-applied polyurethane foam can providethe most cost effective method of convertingloft and barn roofs and walls and meet theever-increasing demand for energy efficientbuildings. PU foam is applied directly to theunderside of the tiles or roofing felt, creatinga warm deck construction without the needfor a ventilated airspace. Only 75mmthickness is required to achieve a U-value ofbetter than 0.25W/m2K. This fits snuglybetween the rafters so that they may be leftexposed as an aesthetic feature. Problems of evening-up irregular surfaces,such as closing the ventilation off at eaveslevel, are easily overcome by building up thefoam to the required profile. After someattention to trimming and removingoverspray, a single coat of bonding plaster islaid to leave an attractive, authentic finish.The design complies with BS 5250: 1989

'Control of Condensation in Buildings' with nooccurrence of surface or interstitialcondensation.

Loft conversions As of the 2006 Building Regulationsamendment to Part L, loft conversions haveto meet a U Value of 0.20W/m2K. Where thetiles/slates are in reasonable condition, sprayfoam can be applied directly to theunderside thus saving the cost of strippingthe roof and providing new roofing felt. Thefoam bonds the tiles together and preventsthe ingress of wind-driven rain snow anddust. The system is applied from the eaves,the ventilation being deliberately closed off,to the ridge so that all unwanted air leakageis eliminated. There is no requirement for aventilated air gap. The system is fullyapproved by relevant BBA certificates and incompliance with Building Regulations. A totaldepth of 120mm of foam is required to meeta U Value of 0.20W/m2K. This can usually beachieved between and behind the existingrafters. Where there is insufficient depth,spray foam can also be used in conjunctionwith other insulation systems such as multi-foils or polyurethane boards over the face ofthe rafters. Foil-faced plasterboard isrecommended to increase the water vapourresistance on the warm side of the insulationand to provide a low emissivity for betterthermal performance.

4

Creates a warm dry useable roofspace

Cavity wall stabilisation andinsulation systemSolving the problems of wall-tie failureand poor levels of insulation usingstructural rigid polyurethane foam. Over the last 30 years polyurethane foamhas been used to stabilise walls sufferingfrom tie failure. Studies made over the lastdecade, in conjunction with the BuildingResearch Establishment, have highlighted theproblem and have confirmed there aremillions of dwellings at risk. A suitablepolyurethane foam system may be injectedinto a masonry cavity wall by injecting liquidpolyurethane through properly spaced holesin the outer leaf. The foam expands in thecavity and sets to become a substantiallyclosed-celled, cross-linked, rigid polyurethanefoam which strongly adheres to the innerand outer leaves, so the leaves becomebonded together. Because of polyurethane’ssuperior bond strength, the system has beenwidely used for the restoration of theintegrity of cavity walls in which the wallties have become ineffective due tocorrosion. The foam is a satisfactoryreplacement for normal metal wall ties.

Superior insulation Cavity reinforcement polyurethane foamshave very good insulation properties and areresistant to flooding. The thermal performanceof a property is improved to meet currentBuilding Regulations within the space of theexisting cavity. This gives energy savings andreduced CO2 emissions.Because polyurethane expanding foamsmould themselves to the fabric of a building,they seal out draughts and reduce air leakage.Closed cell foams are resistant to driving rain,so the foam stays dry, with no loss of thermalproperties. Polyurethane foam systems areapproved under BBA certification for masonrycavity wall constructions in all exposure zones.

Additional stabilisation Polyurethane foam stabilises a wall byadhering to the surfaces of the cavity andproviding a continuous structural connection

between the two leaves. It has the ability toform a good bond with surfaces that areunprepared and in a raw state. The adhesivebond strength is better than 60KN/m2 whichis generally in excess of the wind suctionlikely to occur on the wall.Remedial mechanical fixing systems usingsteel bolts or pins rely heavily on a secure fixto the inner leaf. This is often inadequate andsometimes impossible with hollow blocks. Italso introduces many more thermal bridgesinto the structure which leads to ‘cold spots’.Stabilisation and thermal insulation of cavitywalls is covered by a British Standard Code ofPractice, BS7456. Additionally, you cancontact a BUFCA member for a copy of their BBA Certificate.

Agriculture The agricultural industry is very dependentupon good insulation particularly within rootcrop stores and livestock buildings. Not onlydoes it offer a very good U-value resulting inthe need for less thickness, it also has theadded advantage of being adhered directlyto roof and wall cladding – thus eliminatingvoids for rodents to nest and breed. A further advantage to the system is itsability to completely seal buildings, whichbecomes important for gassing and fogging.

5

Solve the problems of wall-tie failureand poor levels of insulation usingstructural rigid polyurethane foam.

The agricultural industry is verydependent upon good insulationparticularly within root crop storesand livestock buildings.

It also helps ventilation systems to operate totheir full potential. This is one of the mainreasons that the system is favoured withinlivestock buildings. Particularly with pigs andpoultry it allows the farmer to control theventilation and temperature systems farmore effectively and with a dramaticreduction in heating and feed costs. Externally spray applied foam systems arethe preferred option for the insulation of feedbins to eliminate internal condensation andfor insulation of water, fuel and chemicaltanks to protect from frost. The externalapplications are over-coated with weatherproofing polymer coatings to protect fromultra-violet light.Injected polyurethane foam systems are alsoused in pre-formed cavities in both cropstores and livestock buildings eliminatingmechanical and stock damage to the lowerwall areas.

Marine Sprayed and injected P.U. foams are an idealsystem for Marine applications. Their low KFactor (0.023 W/m2K) means that lowerthicknesses are required, giving spacesavings. The material is closed-cell so will notabsorb water and bonds directly to thesubstrate with no voids or joints forcondensation or cold bridging.

Foam systems are available with thefollowing approvals:

■ Class 1 Fire Rating to BS 476 pt 7 (Class'O' variations also available)

■ SOLAS (Saving of Life at Sea) approvalfor life saving devices

■ IMO (Internal Maritime Organisation)Resolution A689

■ MAS (Marine Safety Agency) certified

■ Lloyds Register type approval

■ Norske Veritas approved

BUFCA members will be able to help withrecommending systems and treatments forany of your Marine applications.

External Foam & Coatings External foam and coatings allow large areasto be insulated quickly and easily and, byvarying the depth, achieve any U-valuespecified. Sprayed foams bond permanentlyto any surface that is clean and free fromgrease and moisture. They form seamlesscoatings which cover all contours and minorcracks. A range of elastomeric membranes isavailable to impart the required resistance toUV light. Sprayed PU foams and Elastomericcoatings, have now been used forrefurbishment of existing roofs as well asnew roofs for over 35 years. A range ofsystems is available, many having beentested and approved by the BBA. BritishStandards (BS7021 and BS5211) have alsobeen written.BUFCA members will be able to assist in thedesign of a roof system to meet mostrequirements and supply a full specification,taking into account substrate preparation,primers, if required, suitable foam systems(typically 40-50 kg/m3 for roof applications)and type of weather coating. Systems areavailable for virtually all substrates includingbuilt-up felt roofs, asphalt, sheeted fibrecement, steel, aluminium, slate, concreteand even glass. Once applied, the treatmentis seamless and monolithic and willeffectively weatherproof any roof. Inaddition, the treatment can be applied toany thickness to achieve a required U-value.Dew-point calculations can be made todetermine thickness required forcondensation control.

Class ‘O’ Fire RatedImproved thermal efficiency and fireperformance using polyurethane sprayedfoam and intumescent coating composites Until very recently, designers have had alimited choice of products when it came tospecifying Class O Insulation. Concrete soffits below office blocks, shoppingmalls and airport terminals and air plenumsof air conditioning systems all require a highlevel of effective insulation to preventcondensation. Standard sprayed-fibresystems require extra thickness to meet the

6

Sprayed and injected P.U. foams willnot absorb water so are an idealsystem for Marine applications

Insulates and eliminatescondensation on this factory roof

specified U-value and this, in conjunctionwith a poor bond strength, has lead to anincreasing failure rate. Air currents withinplenums have lead to air erosion problemswith fibre systems, hence the developmentof rigid polyurethane sprayed foam andcoatings satisfying Health & Safetyrequirements, with a fibre-freeatmosphere.The irregular shape of someconcrete soffits poses no problem to PUfoams. The "Spray in Place" technologyensures the insulation will follow any profileseamlessly. The foam is lightweight, offersexcellent permanent adhesion to all buildingmaterials and greatly reduces the costs ofany future maintenance. Its use is notrestricted to soffits. It can be applied in anysituation where compliance for a Class Osurface is required. A typical system wouldcomprise of modified heat-resistant sprayedpolyurethane foam. The only way to protectthis insulation in a fire situation and pass thestringent BS476 Part 6 Fire Propagation Testis to encapsulate it in an intumescentcoating. This provides exceptional fireretardance to the sprayed foam. It does notcontain asbestos in any form. The flameretarding intumescent properties are broughtinto action under heat exposure whenchemicals in the film decompose and swellto provide a carbonaceous foam layer actingas an insulating barrier between the sourceof the heat and the substrate.

Sprayed Polymer Elastomers Now available to BUFCA contractor members,a range of polyurethane and polyurea spray-applied elastomer coatings. These pluralcomponent systems provide flexible,extremely tough monolithic membranes.

Recommended Uses

■ Fishing trawler holds

■ Corrosion control for pipelines

■ Tank linings for primary and secondarycontainment

■ Liner for ponds, lagoons, reservoirs,dykes, irrigation ditches

■ Roof coating – including tanks

■ Sealing manholes from waterinfiltration

■ Protection over sprayed polyurethanefoam against foot traffic and birdattack

■ Hydrogen sulphide protection onsewage effluent sites

■ Styrofoam encapsulation on buoys andflotation devices

■ Truck bed liner

■ Protective coatings on scenicreplications and props for TV/filmstudios

Industrial/CommercialSpray applied foam provides the idealsolution for insulation and condensationcontrol in industrial and commercialbuildings. It can be applied to almost allsurfaces to improve the working environmentand cut fuel costs. Asbestos encapsulation isan added benefit. Applications forpolyurethane foams include factories,warehouses, exhibition halls, footballstadiums and offices. In new and existingstructures PU foams are economically appliedto the underside of steel, asbestos andaluminium roofs and walls. A typical 'K' valueof 0.023 W/m2K gives unsurpassed insulationbenefits reducing 'U' values from 5.0 W/m2Kto 0.25 W/m2K with as little as 85mm offoam. The finished surface is non-toxic andodourless, has low water absorption and highresistance to chemical attack. The resilient

7

Concrete soffits to car parksreceive Class O Fire Ratedpolyurethane foam withintumescent coatings.

surface can be high-pressure jet washed.Class 'O' fire resistant foam systems areavailable which are coated with a singlecomponent, water-based intumescent paint.

Environmental Impact Spray Applied Polyurethane Foam andthe Environment.An independent review of the impact ofthermal insulation on global warming andthe potential for further savings in carbondioxide emissions was carried out recently.The results were reported in a documententitled Thermal Insulation and its Role inCarbon Dioxide Reduction. This report, writtenby Caleb Management Services, highlightedthree significant findings: 1. It was recognised that thermal insulationcan play a key role in the cost effectivereduction of carbon dioxide emissions inEurope and save up to 350 million tonnes perannum by 2010. 2. Retrofitting of un-insulated or poorlyinsulated installations provides by far thebiggest contribution to carbon dioxide savingsand suggests that the targeting of retrofitprogrammes to those member states withaverage carbon dioxide emission rates above0.5kg/kWh for power generation should be prioritised. 3. Insulation materials that can be most easily and efficiently retrofitted need to be prioritised. The report also pointed out that insulationmaterials should be highly efficient in termsof performance at low thickness levels,should have a high strength to weight ratio,should be easy to apply, fibre-free andresistant to moisture. The key requirementslisted above admirably describe theproperties of spray-applied polyurethane (PU)foam. The two-component liquid systemproduces a highly efficient blanket ofinsulation with a thermal conductivity of0.023 W/m2K. It is particularly easy and cost-effective to apply to a wide variety ofsubstrates. Its closed-cell structure renders itvery resistant to moisture ingress and gradesare available which achieve a Class 1 firerating when tested to BS476 Part 7.

PO Box 12, Haslemere, Surrey,GU27 3AH Tel/fax: (01428) 654011 email: info@bufca.co.ukwww.bufca.co.uk

8

Thermal insulation can play a keyrole in the cost effective reduction ofcarbon dioxide emissions

Furthermore it has a very good track recordin retrofit applications, both domestic and industrial. One of the most importantaspects of spray applied polyurethane foamis the fact that it produces a seamlessblanket of insulation giving rise to a productwithout joints. Any jointed system gives riseto potential air leakage leading to asignificant loss of insulation value. In a report carried out into the life-cycleassessment of insulation materials, it wasconcluded that "PUR rigid foam can make animportant contribution to the protection ofthe environment and, especially, throughretrofitting of the existing buildings."

Code of Professional PracticeA Code of Professional Practice has beenproduced by BUFCA to set down standardswithin the spray/injected polyurethane foamindustry to which all member firms willadhere. It is intended to further goodtechnical and professional practice andencourage good relationships betweenmembers of the Association and their clients,from the initial promotion to the after-sales service.

British Urethane Foam Contractors AssociationP O Box 12, Haslemere, Surrey GU27 3AHTel: 01428 870150Email: info@bufca.co.ukwww.bufca.co.uk