One hour CIAT-accredited CPD Seminar for architecture and construction professionals

Loft insulation isn’t working in 80% of UK houses:

What can we do about it?

•  Lo#Insula+onRegula+onsandStandards,Installa+onMethodandMarketPenetra+on

•  ‘In-UseFactors’whichdiminishinsula+onperformance,includingCarbonTrustsurveyonlo#usage

•  Theeffectoflo#insula+oncompressiononU-values•  Safetyrequirementsinlo#s,includingRoSPAlo#accidentsta+s+cs•  Tradi+onalinsula+onandbuildingmethods,whicharenolongerappropriate

•  Alterna+vetechniquestomaximiseinsula+onperformance•  Specificdesignconsidera+onsandU-valuecalculator•  Summary•  TestQues+ons

Orderofcontentofseminar

•  Onaverage,25%ofabuilding’sheatlossthroughitsinsulatedexternalenvelopeisthroughtheroof(source:EnergySavingsTrust)

Lo0insula3on:whyit’sneeded

Typeofapplica3on RequiredU-valueforthelo0ceiling(W/m2K)

Requiredthicknessofthermalconduc3vityinsula3oniflaidattheceilingofthelo0

Newbuild U=0.13(EW&NIBRADL1A)U=0.11(ScotlandSTS6.2)

340mm400mm

Retrofit U=0.16(EW&NIBRADL1B)U=0.13(ScotlandSTS6.2)

270mm340mm

•  Thisassumesthatmineralfibreinsula+onisusedwithathermalconduc+vitykvalueof0.044W/mK(asfoundinthemostcommonproducts)

•  Itispossibletoreduceinsula+onthicknessesbyusingothermaterials•  Itisalsopossibletoinsulateabove,betweenand/orbelowthepitchedroof

ra#ers;thiscreatesa‘warmlo#’.Warmlo#sarenotthesubjectofthispresenta+on.

Lo0insula3on:BuildingsRegula3onsandTechnicalStandards

Note:Don’tForgetOverhea3ng•  Mineralfibreorplas+cthermalconduc+vityinsula+onkeepsheatinduring

winter.but–  Doesnotreadilyletheatoutinthesummer–  Doesnotpreventradiantsolarheatfromenteringthepropertyinthesummer

either–  Inbothcases,leadingtopoten+aloverhea+ng,affec+ng20%ofhousing

(source:ZeroCarbonHomes)•  Considerlo#insula+onwiththeaddi+onalpropertyofhighdecrementdelay/

thermalmass,including:–  Cellulosefibreflake(recyclednewspaper)

•  easyinstalla+onaroundanyframing–  Corkgranules(easyinstalla+on)orboards–  Woodfibrebaisorboards–  Otherplantfibreinsula+onmaterialsinvariousformats

•  ThisisthesubjectofaseparateCPDseminarbyGreenBuildingEncyclopaedia.Contact:forCPD

Step1:layinsula+onbetweenthejoists(usually75or100mmtall)

Step2:rollanotherlayerat90degreestothefirstlayer,togivethetotalrequiredthickness

Thicklo0insula3on:installa3onmethod

•  Ofthe23milliondomes+clo#sintheUK:•  15millionhave>100mmofinsula+on

(Source:DECC,2016)•  Thevastmajorityhavebeeninsulatedusingmineralfibrerolls,usually

selectedforcheapnessandeaseofinstalla+on•  Manyothermaterialsareavailable,whethernatural,non-natural,virgin

orrecycled/re-used.•  Othersformatsinclude:loose,blownorsprayedinsula+on,rigidboard

insula+onandmul+-foils•  AnsimplecomparisoncanbefoundatSuperhomesandmoredetailed

comparisonsareavailableuponrequestfromLo#Zone.

Lo0insula3on:marketpenetra3on

•  Unfortunatelyno,theperformanceisspoiledby:–  Significant‘In-UseFactors’,whichmeansthatlo#insula+ondoesnotworkas

wellasitwasdesignedto

•  Assumingthattheinsula+onhasbeenfiiedcorrectly,accordingtoPAS2030guidelines:–  Withoutgapsand–  Perminngcross-ven+la+onateaves

•  Thenthe‘In-UseFactors’onthefollowingslidecomeintoplay

Islo0insula3on“fitandforget”?

•  Compressionofthelo#insula+ondowntojoistheight–  Storageofbelongingsdirectlyontopoftheinsula+on–  Placinglo#boardsontothejoists

•  Safeaccessdecksinstalledinthelo#,bearingontheceilingjoists–  Usuallywellbelowtherequiredthicknessofinsula+on–  Compressingtheinsula+onaboveandbetweenthejoists

•  Thermalbridgingthroughtheceilingjoists,especiallyifthejoistshavebeenbuiltup,throughtheuseofcross-baiening

•  Householderormaintenancecontractorac+on–  e.g.movingtheinsula+onawaytocreatesafeaccesspathwaysandthennot

beingabletoreplaceitproperly,oratall•  A#erbecomingmoistfromcondensa+onbuildupinthelo#:

–  Insula+ondeteriora+on–  Performancedropoff

SomeCommonIn-UseFactors:

•  Windscourorwindwashingattheeavesandalongthetopoftheinsula+on,drawingheatoutoftheinsula+onsurface

•  Verminaiack•  Wildlifeinhabita+ondisplacingortunnellingthroughinsula+on•  Accumula+onofdustanddebris,especiallya#erroofingwork•  Wateringressthrougholdorleakyroofcoverings

SomeLess-CommonIn-UseFactors:

•  TestsundertakenbytheNa+onalPhysicalLaboratoryshowedthatcompressingmineralfibrelo#insula+on:–  affectstheUvalue–  isverysignificant–  Ismuchworsethanpreviouslythought

•  Compressing270mmto75mm/100mm(typicaljoistheights):

Thebiggest‘In-UseFactor’islo0insula3oncompression

Thickness 270mm 100mm 75mm

Thermalresistancem2K/W 6.11 3.09 2.42

U-ValueW/m2K 0.164 0.324 0.413

Increaseinheatlost - 98% 152%

ObviousexamplesofIn-UseCompression•  Storageofbelongings:directlyontotheinsula+on,orondeckingres+ngon

thejoists–inbothcasessquashingtheinsula+on

•  Fromathermalconduc+vityinsula+onperspec+ve,thislo#ispoor(atleastinthecentralarea)

•  Assumingthereisinsula+onundertheboards,thenitisonlyasdeepasthejoists,anditmaywellhavebeensquashedfromtheBuildingStandardsthicknessdowntojoistheight–whichatleastdoublestheheatlost

Lessobvious,butequallybad

•  BothBuildingRegula+onsApprovedDocumentATable4(seebelow)andBS5268:Part3formoderntrussedra#erroofsrequirethelo#ceilingtosupport:–  0.25kN/m2distributedimposedload(forstorage)

•  (1/8thoftheloadingforadomes+cfloor)–  0.90kNconcentratedpointload(forapersonaccessinglo#,assumedtobethe

loadthroughoneperson’sleg)•  Lightstorageisthereforepermissible,

eventhoughmanybuilderstelltheoccupantsotherwise

•  Notethatmanytradi+onalin-situcut+mberroofsareo#enmuchstrongerthantrussedra#erroofs

Myth1:Moderntruss-ra0erroofsarenotdesignedforstorageinthelo0

•  Actually,theoppositeisoverwhelminglytrue:–  78%ofUKhouseholderssaylo#storageis“veryimportant”or

“essen+al”–  82%usetheirlo#sforstorage

•  Ofthose,78%saytheirsismorethanhalffull–  Only26%knowthatsquashinginsula+onisbadforit(Source:CarbonTrustsurvey,BiggesteversurveyofUKloFusers(6,000responses),2012)

•  69%ofpeopleinfullyoccupiedhomesdonothaveenoughspaceforstorage(Source:CABE,HATC,IpsosMori,quotedinRIBA“CaseforSpace”report,2011)

Myth2:Peoplecanbepersuadednottousetheirlo0forstorage

•  Es+mated1,500hospitalvisitseachyearintheUKowingto:–  fallsfromlo#s–  fallsthroughlo#ceilings(Source:RoSPA,basedonlatestavailablesurveyfiguresforA&Edepartments.DataexcludesfataliTes)

•  Architectsandbuildershavearequirementtodesign-insafemaintenanceunderCDM2015

•  Landlordshavea‘DutyofCare’totheirmaintenancestaff

Safetyinlo0sisalsoanimportantissue:

•  Coldwaterstoragetank,ballvalve,watersupplyanddeliverypipes,insula+onandoverflowpipe

•  Boilertop-uptank,ballvalve,watersupplyanddeliverypipes,insula+onandoverflowpipe

•  Boilerfuelandpowersupply,flues,pipesandinsula+on

•  CommunalorDistricthea+ngflowandreturnpipesandinsula+oniffiied

•  Hotwatercylinderorsolarcylinder,ballvalve,watersupply,overflowanddeliverypipes,andinsula+on

•  Solarthermalpanelexpansiontank,pipesandinsula+on

•  SolarPVinverterandcables

•  PowerShowerPumps•  Extractorfansandducts•  MVHRMechanicalVen+la+onwithHeat

Recoveryduc+ng•  Poweranddatacablesandconduit•  Pipeworkandinsula+on•  TVaerial,satellitedish,cableboxand

cables•  Domes+csprinklersystempipeworkand

insula+on•  Smokedetectorsandcables•  WardenCallsystems•  Ceilingmounteddownlighters•  Ceilingmountedfans•  Ceilingmountedaircondi+oningunits

Safelo0accessisrequiredtoservices:

Safeaccesspla]ormscanbethecauseoftop-upinsula3onremovalorcompression

Lo0insula3oncompressionisalimi3ngfactorinmee3ngtheUK’scarbontargets

•  Theenergyusedbydomes+cbuildingsintheUKaccountsforapproximately25%oftheUK’stotalemissions(Source:CarbonTrust)

•  Andyetwenowseethatlo#insula+onperformsbadlyinsomanybuildings

Ofgemandindependentresearchquan3fica3onoftheIn-UseFactors

•  OfgemassumesthatIUFsreducetheeffec+venessoflo#insula+onby35%.Forexample,thisismandatedinlegisla+onfortheECOscheme(Source:ECOMeasuresTable)

•  SubsequentresearchcollatedbyLo#Zoneshowsthistobeanunderes+mate,since27.5%isforlo#insula+oncompressionalone(Source:WhitePaperonLoFInsulaTonIUFs)

Sowhatarethesolu3ons?•  Raising+mberpaneldeckingabove

exis+ngjoistswithso#woodframingorjoists?

•  Deckingontopofrigidfoamed-plas+c

boards?

•  Proprietarysupportsanddeckingsystems?

Cross-Ba^eningusedtobecommon

•  Theextra+mberis:–  Heavyandawkwardtogetinandfitinaconfinedspace–  Itmayuseupasignificantpropor+onoftheloadbearingcapacityofthelo#

floor–  Unabletocopewithunevenjoistheights–theresul+ngdeckwillbeuneven–  Unabletocopewithservices(e.g.pipes)laidontopofthejoists–thesegetin

thewayofthenew+mber•  Installersmustremembertoputbackinplaceanyexis+ngtop-upthermal

conduc+vityinsula+onbeforedeckingover•  Takingcaretofitgap-freeinsula+onaroundframingorjoists•  O#enhardtoinspectforqualityofworkoncetheboardshavebeenscrewedon

top

Butraising3mberpaneldeckingonso0woodframing/joistsisnolongergoodprac3ce

•  Theextra+mberactsasathermalbridgethroughtheinsula+on–  Linear(ifontopofjoists)orPoint(iflaidatrightanglestoexis+ngjoists)

•  PartL1Aofthe2013BuildingRegula+onsinEnglandandWalesmandatethatPsivaluesforthesethermalbridgeshavetobeallowedforintheU-valuecalcula+onfortheroof

•  Thiswillrequireanincreaseinthermalconduc+vityinsula+onthicknesstocompensate–  Ifthereisnoroominthelo#loca+on,itwillbeneededelsewhere

WatchoutforPartL1Aofthe2013BuildingsRegula3ons!

Deckingontorigidfoamedplas3cinsula3on?

•  Foamedplas+csinsula+onarenotnormallymoisturepermeablesovapourbarriersareessen+al-butdifficulttoaddtoexis+ngceilings

•  Thelackofavapourbarriercancauseinters++alorsurfacecondensa+on,asmoistairpassingthroughtheceilinginsula+onwillcoolandmaycondenseontheundersideofthedeckboard

•  Forconven+onalpitchedroofcross-ven+la+onitisrecommendedthatthereisatleastanadequateairgapbetweenthetopoftheinsula+onandtheundersideofthedeckingboard(source:BRE)–  Thismeansthataddi+onal+mbermustbeusedtoraisethedeckingabove

therigidinsula+on.Butthishasthesameproblemascross-baiening.

Risksassociatedwithusingrigidfoamedplas3csinsula3on(1)

•  Rigidfoamedplas+csinsula+onmustnotbeallowedtotouchplas+cconduitorplas+csheathingofelectricalcables–  Polymermigra+onmaymodifytheperformanceofbothplas+cs

•  Plas+cscandissolveaway–  Atpar+cularriskareexpandedorextrudedpolystyrenerigidfoamedplas+c

orrigidboardinsula+on,andpolyurethanesprayfoam–  Thereismoreinforma+oninatechnicalpaperon“

Themigra+onofplas+cisersfromPVCcablesheathingintoexpandedpolystyreneinsula+on”.

•  Finally,onaprac+calpoint,largesec+onsofrigidinsula+on/deckingarealsohardtogetthroughthelo#hatchandfitwithinaconfinedlo#space,withoutgaps

Risksassociatedwithusingrigidfoamedplas3csinsula3on(2)

•  Overaperiodofyearstherewasareac+onbetweentheplas+ciserinthePVCcablingandthepolystyreneinsula+on,wherebytheplas+cisermigratedoutofthePVC,so#eningthestyrenewhichadheredtothePVC,leavingabriilecablethatcrackedandsplit,exposing

Exampleoffirecausedbypolymermigra3on

liveconductorswhichcausedafireinvolvingthe+mberswithinthelo#space.(Source:EastSussexFireandRescueService)

•  Thereareanumberofnewproductsandsystemsonthemarket•  OnlyonesystemhasbeenapprovedbyBBAforuseinconstruc+on:

–  Itisstrongenoughtowithstandtherequiredloading–  Itistallenoughtomeetmostmoderninsula+onthicknesses–  Itavoidscrea+ngasignificantthermalbridgethroughtheinsula+on–  Ithasaven+la+ongaptoavoidsurfaceorinters++alcondensa+on

•  ThatsystemisLo#ZoneStoreFloor(www.lo#zone.co.uk)•  BBACer+ficate15/5269

Newraisedlo0deckingsystems

Lo0ZoneStoreFloor:plas3csupportsandmetalbeamstoraise3mberpaneldecking

Lo0ZoneStoreFloorinstalla3ons(1)

Lo0ZoneStoreFloorinstalla3ons(2)•  Innewbuildtruss-roofresiden+alproper+es

Lo0ZoneStoreFloorinstalla3ons(3)•  Alsousedforsafeaccesswalkwaysinnon-domes+cbuildings

DesignConsidera3on1:DoestheLo0Zonesystemcauseasignificantthermalbridge

throughitssupports?

•  Noitdoesnot.TheBuildingsResearchEstablishmentcalculatedthatthethermalconduc+vitythroughtheplas+csupportswasnegligible,becauseoftheirmaterialchoiceandbecauseofthesmallcontactareas

•  TheyneednotbeconsideredinU-valuecalcula+ons•  Seenextslideforscreenshotfromthereport

Thermalbridgethroughsupports?

DesignConsidera3on2:SizeofVen3la3onGap•  Theven+la+ongapneededtoreducetheriskofinters++alcondensa+onis

dependentonthehumidityoftheairandtheven+la+onlevelsinthelo#•  50mmbetweenthetopoftheinsula+onandtheundersideofthedecking

boardsisdefaultprac+ceandrecommendedbyBBA•  BREcalculatedthata29mmven+la+ongapwouldbesufficient,solongas

therewasadequateven+la+oninthelo#(e.g.fromtheeaves)•  TheLo#Zonesupportsare279mmtallandareplacedontotheexis+ngjoists

(whichareusually75mmor100mmtall).Thisgivesupto350mmdepthforinsula+onplusa29mmair-gap.Shouldtheinsula+onlevelsbedeeper,thentheLo#Zonesupportswouldberaisedupwithsmallsec+onsof+mberdirectlyunderneaththesupport(noneedtocross-baienhowever).

Client Report: Hygrothermal assessment of LoftZone floor Client report number 275586 Prepared for: Pier Cave LoftZone Ltd 28 November 2011

ToolforDesigners:GBECalculator

•  ThereisafreetoolfordesignerstoselectrequiredmaterialschoicesandcalculateU-valueswhenlo#deckingisneeded

•  GBECalculatorLo#ZoneStoreFloorUValueA05BRM100117XLSX(linkopensExceldocument)

•  Lo#insula+on‘In-UseFactors’,inpar+cularcompression,areamajorissue•  Significantnumbersofhousesareaffected,addingconsiderablytoUK

energyandfueldemandsandcarbonoutputsofUKhousing•  Storagespaceishighlyimportantinbuildings•  Safeaccesstothelo#formaintenancepurposesneedstobedesignedinby

architectsandbuilders•  Mosttradi+onalmeansofsolvingtheneedforstoragespaceandsafe

accesswalkwaysarenolongergoodprac+ce•  TheLo#ZoneStoreFlooristheonlyproductforthispurposethathasbeen

approvedbyBBAforuseinconstruc+on.

Summary

1.  Whatpercentageofhouseholdsusetheirlo#forstorage?(35%,50%,82%)2.  Iflo#insula+oniscompressedfrom270mmto100mmjoistheight,byhow

muchdoestheU-valuechange?(Ithalves,itdoubles,itstaysthesame)3.  WhatisthegaprecommendedbyBREbetweenthetopoftheinsula+onand

theboiomofthedeck,topreventsurfacecondensa+onontheundersideofthedeckboards,assumingadequateven+la+oninthelo#?(29mm,50mm,82mm).

4.  WhatdoesOfgemconsiderthetotalreduc+onintheeffec+venessofUKlo#insula+onowingtoallIn-UseFactorstobe?(35%,50%,82%)

5.  Whatistherequirementfortheloadingoftheboiomchordoftrussedra#erroofs?(0.25kN/m2distributedimposedloadplus0.90kNconcentratedpointload0.50kN/m2distributedimposedloadplus0.90kNconcentratedpointload0.82kN/m2distributedimposedloadplus0.90kNconcentratedpointload)

6.  Underwhichregula+onsarearchitectsandbuildersrequiredtodesigninsafemaintenanceaccess?(PartL1A,WorkingatHeightRegula+ons,CDM2015)

TestQues3ons:

1.   82%ofhouseholdsusetheirlo#sforstorage2.  Uvaluedoubleswheninsula+oncompressed270to100mm3.   29mmcross-ven+la+ongapisrecommendedbyBRE4.  Ofgemconsider‘In-usefactors’reduceUKlo#insula+oneffec+venessby

35%5.   0.25kN/m2distributedimposedloadplus0.90kNconcentratedpointload6.   CDM2015requiressafemaintenanceaccesstobedesignedin

TestAnswers: