We want to build, is what is being offered to us okay?

Hello, we would like to start building our own home this year with a developer, everything from a single source. Since I am not familiar with the subject despite a lot of reading to be able to evaluate such things, I wanted to ask what you can tell us about the offer we have. At the moment, we are strongly leaning towards this provider. We would be interested to know whether this is "standard" or rather low level. Or what could possibly be improved without having to pay several thousand more again.

First of all, many things are specified as "wärmegedämmpt," such as the lowered ceiling in the bay window, the roller shutter boxes, or the massive knee wall.

Floor:
Reinforced concrete slab foundation including frost protection strip as well as sealing against rising moisture instead of strip foundation formation. Thickness approx. 20 cm and concrete quality C 20/25. Reinforcement steel and slab thickness according to the assumed ground pressure according to the client’s performance specifications (I can add this if desired). A foil is laid under the slab as a cleanliness layer.

Wall:
The exterior walls are constructed with a total thickness of approx. 44.5 cm as follows: 1.5 cm thick fine plaster 17.5 cm masonry as porous, fired clay brick 14 cm core insulation, WLG 035 approx. 11.5 cm facing brick masonry Interior walls on ground and attic floors are constructed with brick masonry (Poroton).

(Now the addition for KFW70)

The installation of the pipes for the underfloor hot water heating is designed for a supply temperature of 35°C by closer spacing of the pipes.

Extension of roof insulation to 26 cm in WLG 035 (credit if dropped 4,216,-) [is that okay for somewhat more insulation and more closely spaced pipes?]

When upgrading to Kfw55 (20k-21k) Different heating with more solar. Ventilation system. 8 cm insulation WLG 035 under the slab. Exterior walls then apparently no longer clinker but plastered 1.5 cm thick fine plaster 17.5 cm masonry as porous, fired clay brick 20 cm continuous thermal insulation PST, in WLG 032 including silicate façade plaster.

Now the question arises for me, since I would like a ventilation system, whether I should improve something in the insulation even without aiming for KFW55, and if the wall construction with 17.5 cm is not too little? I have scanned through a forum where exactly this wall construction (same developer) was torn apart.

Are you building with a basement? There is no base insulation listed. Wall insulation is okay. Let me explain to you what "tightly" laid pipes/conduits are... what that means. 26 cm is quite something - but why not (it's more towards Kfw40 - if you can look at it in terms of insulation). You can also simply put 2 cm more insulation wool in the wall... but okay. The wall construction is - if structurally okay - good. If you like KFW55, tell the supplier to add 2 cm more wool. What kind of bricks are those? What is their thermal conductivity? I would definitely do ventilation - even in our apartment (from the 90s) the need for shock ventilation is annoying. You could do the 8 cm under the slab. What kind of windows will be installed? What Ug, what Uf?

No, we are building without a basement. So which exact bricks are used is not specified. There is also unfortunately nothing about the WLG, just that the insulation is then WLG 035. When he said "installed closer," he meant that this might already provide a "preparation" in case an air-water heat pump should be retrofitted/converted sometime in the future. So would you recommend the bottom-insulated slab? Even without aiming for KFW55? The windows have triple glazing with a Ug value of 0.7.

What does guessing mean - I am not an expert: I believe a construction expert is against it, because you lack long-term experience (compression of the material). Depending on the house, however, this does make up part of the heat loss. "possibly already a 'preparation' is nonsense" is the statement... he should say how many cm or what the concept looks like. You can ask about the surcharge for Ug 0.5.

So 18 lines as a construction description are already quite little.... Under about 40 pages it won't work.

Probably won't be the whole thing - ours didn't have 40 pages either