Ground slab with strip foundation and frost skirt

: Of course, but laying down a few tiles is not really a task that would keep a whole construction crew busy for days. I think we took about 2-3 hours as two inexperienced people for our 35m². With a basement, where the stuff has to be glued to the walls, it is naturally a bit more effort.

Interesting discussion. According to the general contractor, only the basement walls are to be insulated here, not under the basement floor. At first, I was surprised, as a heating system is supposed to be installed there after all. Upon inquiry, I was told that it is not necessary and not economical because the basement floor is already frost-free. It is only mandatory if you want to upgrade the basement to KfW55.

But if I take the price from above alone and a basement floor area of around 110m², then the additional cost cannot be recouped with energy savings. Or are there other opinions on this?

How warm/cold is the ground actually at a depth of 3-4 meters?

The profitability directly depends on the price asked and accordingly any measure could be rendered absurd by a correspondingly greedy GU.

XPS in 120mm thickness can be obtained for 10€/m² gross. If the GU wants another 15€/m² for unpacking and laying it down, it naturally gets tight.

That's how it looks; it's usually only economical if you do it yourself.



The ground temperatures:

What the site manager of the TE says is fine. Of course, being completely wrapped up is better, but you can also make more mistakes that way.

: Sure, but laying down those few boards is not a task that would keep an entire construction crew busy for days. I believe the two of us, inexperienced, took about 2-3 hours for our 35m². With a basement, where the stuff has to be glued to the walls, it’s naturally a bit more effort.

Without a basement, I agree with you, but in our in-situ concrete basement, the boards were placed into the construction before pouring. I can’t do that and I don’t want to.