000			02092nam a22001697a 4500
008			240402t2024 xxk|||||o||||o00| 0 eng d
245			_aMoisture risk of spray foam insulation applied to timber sloped roofs _bModelling of moisture risk for retrofitted spray foam insulation in existing dwellings _h[Electronic resource]
260			_aLondon, _bHealth and Safety Executive _c28 March 2024
300			_a78p.
520			_aBuilding Safety Regulator of the Health and Safety Executive modelling investigates the level of moisture and timber degradation risk which may be encountered when a sprayed foam insulant is applied to typical domestic timber roofs. The modelling indicates that risks are low when an open cell (moisture permeable) insulant is applied in line with guidance described in British Standard BS 5250:2021. Levels of theoretical risk vary with the temperature conditions when the insulant is applied directly to a low resistance underlay. Low levels of risk were found in a climate considered typical for London for all scenarios. Medium levels of risk were found in a climate considered typical for Newcastle for most scenarios. The modelling identified higher levels of risk in some scenarios when a sprayed foam is applied to high resistance underlay. In particular, high risks were determined in London when open cell insulation is applied with no Air and Vapour Control Layer (AVCL) present, reducing to low risks when a closed cell insulant and/or an AVCL is used. High levels of risk were also identified in Newcastle, which were reduced to a medium or low risk by the presence of an AVCL. The highest risk assessed is when spray foam insulation is applied directly onto the roof covering. This leads to high risks under all modelled scenarios.
650			_aSpray Foam
650			_aInsulation
690			_96223 _aBuilding materials & defects
710	1		_aHealth and Safety Executive _9491
856			_uhttps://www.gov.uk/government/publications/moisture-risk-of-spray-foam-insulation-applied-to-timber-sloped-roofs _zAvailable from HSE
942			_2ddc
999			_c121873 _d121873