Floor construction in new buildings & basements

Not bad, I basically did it similarly, just shifted upwards in parallel. Should just about meet the energy saving ordinance according to the plan. It should just barely still be enough for 55er. Since I have no funding, but whatever. I laid everything myself up to just below the Rolljet, that way you know what you've got.

Hi, we also have a solid wood construction and in my apartment (one of four in the house) a wooden floor. However, without underfloor heating but with wall heating. Thanks to the Passive House standard (including KfW40+ ...), the floor is never cold despite the lack of underfloor heating, at most "cooler than the rest." For me always pleasant because wood never feels as cold to me as, for example, unheated tiles.

Construction: 8cm PUR under the floor slab (30cm perimeter insulation...), 30cm thick floor slab fully taped with bitumen. On top of that, 25cm floor construction in my case. All cables and (controlled residential ventilation/water etc.) pipes in the floor, cross beam layer (top layer at about 45cm intervals) on rubber buffers and in between simply 032 glass wool in 2 layers laid crosswise. On top 18mm OSB plus 1.5mm impact sound insulation (some eco stuff from Wineo made from castor oil ;)), then 16mm oak parquet. Unless some idiot opens the house and terrace door at the same time in winter so that icy cold air sweeps over the floor, temperature-wise everything is tip-top. And since I live alone, the idiot can only occasionally be me :D

Insulation of the floor slab is only counted with a factor of 0.5 in the Energy Saving Ordinance or KfW calculation. So if the U-value is 0.245, then the value for the calculation is 0.123... and this value is compared, for example, with a wall with 0.12 or something. When installing the insulation, not 1 x 120 mm, but crosswise 2 x 60 mm. This is better to avoid thermal bridges against unheated spaces or soil. Electrical installation in the lowest insulation layer, water pipes as simply insulated pipes laid on the first insulation layer, i.e., in the upper insulation layer. The hot water pipe is thus insulated downwards with 70 mm. Afterwards, only the HB tack strip.

In our Kfw40 house, there is 20 cm of insulation under the floor slab (no basement). Originally, 6 cm of PUR was planned on top of that (energy consultant) and directly on top of that 30mm solid wood planks. In consultation with the energy consultant, we replaced the PUR and used wood fiber insulation with a lower value under the planks. From time to time, I was annoyed that I hadn’t left more space for insulation, but I let myself be talked down by the general contractor. You always think that more is better or you prefer to be too cautious (in this case, I was not). The status quo is that I don’t have a worse feeling on the ground floor than on the upper floor, where the same floor is installed, and we don’t have underfloor heating either. I always remember our former house built in 1990, where the bedroom was in the ground floor/basement. There was standard insulation with screed and a carpet on top, and I would never have thought it was too cold there. Nevertheless, next time, I would choose more than 6 cm of insulation thickness, if only to have more room for pipes, cables, etc., which caused quite a bit of trouble.