Cost calculation for 65m² residential basement KfW 40 insulated including earth excavation

Hello dear forum,

We are currently planning our house and would like to contract out the basement separately to save a few euros.

What costs should I realistically expect in the Hessische Bergstraße area? Does anyone know a local, inexpensive, and good provider?

The scope of services would be like this, or something similar (feel free to add)

- Earthworks including storage & transport of excavation material
- Perimeter insulation under the floor slab
- External wall waterproofing according to DIN 18195 part 4
- Grounding cable embedded in the floor slab
- Ceiling height so that there is 2.4 m room height
- Creating the clean layer 5-10 cm, including creating a sand & gravel filling underneath
- White tank including multi-utility house entry Nord-Ost
- Basement exterior walls as well as floor slab including reinforcement, drainage, and foil
- Also house execution to the carport (East) and terrace (West)
- Insulation as a residential basement according to KfW 40 standards
- Creation of assembly plans
- Structural calculation
- Specialist construction service
- String line framework
- Drainage as insulating formwork
- Flushing pipes for corner point drainage with 2 cleaning shafts (Nord-Ost and Nord-West)
- Sealing package
- Built-in parts (windows, light wells, doors, and basement stairs)
- Empty conduits for water, wastewater, and electricity

Thank you very much in advance.

Living space quality, high ceilings, KfW-40... I don't think you will come in far under 100K there. Earthworks are extra, depending on the type of soil you have and what local disposal costs, that is very individual. Ask other builders in the development area what offers and soil reports they have for an initial estimate (rough).

And I doubt that you really save that much by leaving the basement out of the house construction. The interfaces of the two building structures with KfW-40 can contain tricky details and let me guess - you are appointing the site manager personally.... and even if it's just delays, those also cost a lot of money in construction.

If I remember correctly, your construction project has the special issue of a very unusual basement, namely that from the perspective of the ground floor footprint it is only a partial basement and thus the ground floor still overlaps the basement ceiling, on the other hand the basement extends beyond the house on the valley side, namely continuing under the terrace as well. This is likely to make the market of providers for the realization of your project quite narrow – with the result of correspondingly weak competition.

If I remember correctly, your construction project has the special problem of a very particular basement

So first of all, hats off to you for remembering correctly. It's been a while since I put that up for discussion.

We have taken the advice from the forum to heart and fundamentally revised the floor plan, so although the plot is the same, the house is completely different.

However, I didn't want to discuss the new floor plan in the forum again at the moment.

We decided for efficiency reasons to have a full basement and to have it completely insulated as living space. Of the 65 m² basement, about 45 m² would be living space and a little less than 20 m² utility space and storage areas.

I assume that any basement builder who would basically build the basement on such a slope can also implement it technically.

Thank you very much for your feedback

Write that the provider should add missing information for the cellar construction. Then the list will definitely be correct. The ground class will play a role in the price, especially if it is rocky.

We took the advice from the forum to heart and fundamentally revised the floor plan, [...] However, I did not want to discuss the new floor plan again in the forum at the moment.

However, it is advisable (preferably in the existing floor plan thread). With your property, you should take advantage of having found a forum where someone engages with your overall building project. Of course, this is only possible to the extent that the helpers are fed with facts. The jeers from the opposite fan section can be ignored.