Sustainable Retrofit - Regensw
Sustainable Retrofit A ‘fabric first’ approach
Mark Elton Technical expert panel member Energy Saving Trust
Improving the building fabric A technical and business opportunity guide covering:
• Thermal insulation and bridging • Air tightness and moisture control • Floor insulation • Wall insulation (cavity, internal & external) • Roof insulation (loft, pitched & flat) • Windows and doors
Common barriers and constraints for thermal upgrades • planning status • architectural considerations • structural considerations • occupation • room layouts • boundary conditions
Thermal bridging in retrofits • eliminate where feasible • mitigate residual thermal bridges • aim to avoid surface condensation
Thermal bridging in retrofits
Reducing air leakage in retrofit
Controlling building fabric moisture • reduces heat losses • combats draughts and discomfort • protects building fabric
Floor insulation
Floor insulation
Main retrofit considerations: • improve U-values with insulation between and above or below timber floors • maintain cross-ventilation below • consider air tightness improvements • improving temperature stratification Retrofit disadvantages: • disruption • raised floor level impacts on doors etc
Floor insulation
Floor insulation
Cavity Wall Insulation Main retrofit considerations:
• cavity width suitable • ensuring coverage and continuity • materials v performance Retrofit opportunities:
• low cost measure • financial incentives • £8m unfilled cavities
External Wall Insulation Main retrofit advantages:
• little disruption or loss of living space • EWI protects fabric & improves appearance • min thermal bridging & condensation risk • little maintenance – no internal decoration Retrofit considerations:
• external finish options • junctions with eaves, gables, windows etc • can services be relocated?
External Wall Insulation
External Wall Insulation
Internal Wall Insulation Main retrofit advantages: • no planning permission reqd • incremental installation • no scaffolding required • ease of continuity w floor and loft insulation Retrofit considerations: • thermal bridging and condensation risk • air barrier sequencing • impact of loss of space • relocation of services
Internal Wall Insulation
Internal Wall Insulation
Loft (Ceiling) Insulation
Loft (Ceiling) Insulation Main retrofit considerations:
• avoiding thermal bypass • maintaining adequate cross ventilation • reducing air leakage to rooms below Retrofit options:
• consider blown insulation • replace loft hatch • replace ceiling finish with OSB deck and service void?
Loft (Ceiling) Insulation
Pitched Roof Insulation
Pitched Roof Insulation
Main retrofit considerations:
• add insulation in a practical manner • minimise thermal bridging of roof members • maintaining ventilation behind roof finish • reducing thermal bridging Retrofit decisions:
• replacement of roof finish? • insulate above or below roof structure? • interface with EWI or IWI measures?
Pitched Roof Insulation
Pitched Roof Insulation
Flat Roof Insulation
Main retrofit considerations: • increasing U-values • maintaining the waterproof membrane • reducing thermal bridging at jct with EWI • accounting for security and post Retrofit decisions: • use rigid insulation boards? • warm or inverted roof? • overlap and maintain continuity with EWi
Flat Roof Insulation
Windows
Main retrofit considerations: • increasing frame and leaf U-values • reducing air leakage • reducing thermal bridging at reveals • supporting the ventilation strategy
Retrofit strategies: • refurbish existing window system • secondary glazing • replace windows independently • replace windows concurrent with EWI or IWI measures
Window retrofit options
Window retrofit options
External doors
Main retrofit considerations: • increasing frame and leaf U-values • reducing air leakage • reducing thermal bridging • accounting for security and post Retrofit strategies: • refurbish existing door leaf • independently replace door and frame • replace door and frame concurrently with EWI or IWI measures
External doors
Mark Elton Technical expert panel member Energy Saving Trust
Improving the building fabric A technical and business opportunity guide covering:
• Thermal insulation and bridging • Air tightness and moisture control • Floor insulation • Wall insulation (cavity, internal & external) • Roof insulation (loft, pitched & flat) • Windows and doors
Common barriers and constraints for thermal upgrades • planning status • architectural considerations • structural considerations • occupation • room layouts • boundary conditions
Thermal bridging in retrofits • eliminate where feasible • mitigate residual thermal bridges • aim to avoid surface condensation
Thermal bridging in retrofits
Reducing air leakage in retrofit
Controlling building fabric moisture • reduces heat losses • combats draughts and discomfort • protects building fabric
Floor insulation
Floor insulation
Main retrofit considerations: • improve U-values with insulation between and above or below timber floors • maintain cross-ventilation below • consider air tightness improvements • improving temperature stratification Retrofit disadvantages: • disruption • raised floor level impacts on doors etc
Floor insulation
Floor insulation
Cavity Wall Insulation Main retrofit considerations:
• cavity width suitable • ensuring coverage and continuity • materials v performance Retrofit opportunities:
• low cost measure • financial incentives • £8m unfilled cavities
External Wall Insulation Main retrofit advantages:
• little disruption or loss of living space • EWI protects fabric & improves appearance • min thermal bridging & condensation risk • little maintenance – no internal decoration Retrofit considerations:
• external finish options • junctions with eaves, gables, windows etc • can services be relocated?
External Wall Insulation
External Wall Insulation
Internal Wall Insulation Main retrofit advantages: • no planning permission reqd • incremental installation • no scaffolding required • ease of continuity w floor and loft insulation Retrofit considerations: • thermal bridging and condensation risk • air barrier sequencing • impact of loss of space • relocation of services
Internal Wall Insulation
Internal Wall Insulation
Loft (Ceiling) Insulation
Loft (Ceiling) Insulation Main retrofit considerations:
• avoiding thermal bypass • maintaining adequate cross ventilation • reducing air leakage to rooms below Retrofit options:
• consider blown insulation • replace loft hatch • replace ceiling finish with OSB deck and service void?
Loft (Ceiling) Insulation
Pitched Roof Insulation
Pitched Roof Insulation
Main retrofit considerations:
• add insulation in a practical manner • minimise thermal bridging of roof members • maintaining ventilation behind roof finish • reducing thermal bridging Retrofit decisions:
• replacement of roof finish? • insulate above or below roof structure? • interface with EWI or IWI measures?
Pitched Roof Insulation
Pitched Roof Insulation
Flat Roof Insulation
Main retrofit considerations: • increasing U-values • maintaining the waterproof membrane • reducing thermal bridging at jct with EWI • accounting for security and post Retrofit decisions: • use rigid insulation boards? • warm or inverted roof? • overlap and maintain continuity with EWi
Flat Roof Insulation
Windows
Main retrofit considerations: • increasing frame and leaf U-values • reducing air leakage • reducing thermal bridging at reveals • supporting the ventilation strategy
Retrofit strategies: • refurbish existing window system • secondary glazing • replace windows independently • replace windows concurrent with EWI or IWI measures
Window retrofit options
Window retrofit options
External doors
Main retrofit considerations: • increasing frame and leaf U-values • reducing air leakage • reducing thermal bridging • accounting for security and post Retrofit strategies: • refurbish existing door leaf • independently replace door and frame • replace door and frame concurrently with EWI or IWI measures
External doors
