ᐅ Is aerated concrete with a density class of 30 sufficient for a KfW 70 energy-efficiency house?
Created on: 3 Jan 2013 19:38
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At the beginning of February, we plan to start building our single-family house (solid masonry). It should meet the KfW 70 standard. Our builder has proposed using 30cm (12 inches) aerated concrete blocks for the exterior walls, built in a "monolithic construction" method, plus a two-layer mineral plaster with a thickness of 15mm (0.6 inches). We have no expertise in this area and are wondering whether this wall structure can meet the KfW 70 standard. The blocks themselves do not have a particularly good U-value.
TheMasterofBau schrieb:
When I asked about the thermal insulation calculation, my builder just shrugged and referred to his "many years of experience." He said it would probably "work out"... I’m going to spend the extra money and hire an energy consultant to check it. I won’t accept anything like that at all. What if those many years of experience were bad ones?
The builder has to provide proof, and it must be in writing. There is no alternative.