This page describes a representative engineering scenario for this application type. It is written to illustrate how the material is selected and what typically changes as a result. It is not an account of a specific named customer project.
The situation
A listed terrace is being converted to apartments. The facade cannot be altered, so insulation must go inside. Conventional internal wall insulation at the thickness needed for the target U-value would take two of the planned units below the minimum room size, which means they cannot be let.
What the real comparison is
Compared per square metre of material, aerogel panel is several times the price of mineral wool and the decision looks obvious in the wrong direction. Compared against the capital value of the floor area that conventional insulation would consume, the calculation reverses, often decisively. On a scheme like this the recovered lettable area can exceed the entire insulation package cost.
The approach
- Aerogel panel on external walls to reach the target U-value in roughly a third of the thickness
- Thin panel at reveals and lintels, where thermal bridges would otherwise drive condensation risk
- Vapour open build-up appropriate to solid masonry, so the wall can still dry inward
- Class A1 material, which simplifies the fire strategy in a converted multi-occupancy building
What typically changes
- All planned units stay above minimum room size and remain lettable
- Thermal bridges at reveals are treated rather than accepted, reducing mould risk
- The external appearance is untouched, which is what made consent achievable
- The insulation package cost is offset by retained floor area
Talk to us about your project
Send us your line list, drawings or target U-values and we will come back with a thickness recommendation, a bill of material and a quotation. Contact our technical team.