4 ms·
The quoted cost is half that of a traditional build, but I think it would be fairer if they compared it against a similarly finished traditional build - ie with
by djaychela 2y ago
The quoted cost is half that of a traditional build, but I think it would be fairer if they compared it against a similarly finished traditional build - ie without any finish on the interior walls (plaster or similar) and so on.
I'm wondering what the thermal performance is like as well - certainly here in the UK the internal leaf of a cavity wall is usually made of aerated concrete blocks which have very good thermal performance compared to solid concrete ones.
- londons_explore 2y agoIn a cavity wall, it is the insulated cavity that provides 99% of the insulation. The inner and outer bricks, of whatever type, are so conductive that they can pretty much be ignored. The reason aerated bricks are used is because they are lighter, and therefore cost less to produce and transport, and are therefore used wherever the structural engineer can get away with it.
- djaychela 2y agoThat is simply untrue. I've just self built an extension and it would not pass building regs if the inner leaf was made of heavy concrete block or standard brickwork (both of which were desired for stylistic reasons). The specific blocks used were 1.21 W/mK externally and 0.06 W/mK for the internal aircrete blocks. That's an enormous difference. UK government research indicated a 100mm cavity may be 0.6, so the inner leaf is still doing most of the work. Adding insulation to this cavity massively increases its performance, but the materials are better insulators than the air, and the concrete blocks are the worst part of the system. [1] - https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/48187/3146-thermal-transmittance.pdf https://assets.publishing.service.gov.uk/government/uploads/...