Alternative Wls 035 on 032

Hello everyone,

according to the Energy Saving Ordinance according to Kfw 70, the roof insulation is intended....

between-rafter insulation 035 200mm and under-rafter insulation 035 40mm.

Could the USB be omitted and instead a ZSD with 032 200mm be used? the U-value changes from 0.158 to 0.156.

The Energy Saving Ordinance does not specify insulation thicknesses or constructions. You can at most infer them from it. By the way, KFW 70 no longer exists. You should discuss the change of the roof structure with your architect, the insulation material with your energy consultant (or whoever calculates the thermal protection certificate). The same/better U-value is hopeful. But eo do you get WLG 032 stone/glass wool from? Or are you insulating the roof with EPS?!

Hello everyone,

according to the Energy Saving Ordinance for Kfw 70, the roof insulation is specified as....

between-rafter insulation 035 200mm and under-rafter insulation 035 40mm.

Could one do without the under-rafter insulation and instead use a ZSD with 032 200mm? The U-value changes from 0.158 to 0.156.

That is possible, the only question is what will be cheaper overall.

Hello Alex85,

the 032 200mm clamp felt would even be almost 200€ cheaper. They are already available from several brands like Urs***, Isov*** and Co. I have an acquaintance in the building materials trade. I have now directly spoken to the creator of the energy saving ordinance, seems to work. I could have thought of that before too :-)