Construction project single-family house 140 sqm with basement

Dear community, first of all, a big compliment for the super helpful tips here. I have been planning or trying to plan our house for half a year. We have already been to the architect and want to build solidly. How do you assess our project from a cost perspective?

-Single-family house with 140 sqm and fully basement
-Standard according to the Energy Saving Ordinance
-Refrigerator with WDVS
-square, practical, without dormers, bay windows, etc.
-7.49*11.49* external dimensions
-1 bathroom upstairs, 1 guest shower bathroom downstairs
-Ground floor open living area, with chimney (unnecessary extra, but we do not want to miss the stove for coziness)
-3 bedrooms upstairs
-Basement 1 developed room as office, 3 storage/technical/utility rooms
-A air-to-water heat pump is planned, underfloor heating
-Controlled residential ventilation with heat recovery
-Triple-glazed windows with blinds
-Floor according to soil survey, simply sandstone floor, so best conditions, no pressing groundwater,

So, now the architect gave us a rough estimate and said we should calculate with 400 Euros per m3 (796 m3)
this seems rather high to us. For prudence, we will also design our loan accordingly, since someone can always become ill or take longer off.
However, we want to contribute a lot of our own work.
Heating, electrical, roof with beams to open up, sanitary, laying floors, plastering will be done by ourselves.

Do you think we could manage with around 200k if everything goes optimally and it works out this way? This only concerns the house construction costs, everything else like outdoor facilities, garage, terrace will be contracted separately.

Short and to the point: Definitely not. If you're lucky, you might just barely not touch the 350k€ with a whole lot of EL.

That would be 70k€ less than I did without EL.

I'm building 139sqm with a basement myself. My architect also calculated 400€ per cbm.

The equipment is very, very similar, just with bricks without WDVS but no Raffstores.

Phew, that sounds intense. What exactly is so expensive about it? No waterproof concrete shell, no golden faucets, everything kept simple and standard... And that’s supposed to cost 420k?! To my knowledge, KL and the surrounding area aren’t exactly the most expensive region in Germany. I’d really be interested to know what the price drivers are, especially since so much is done by yourself.

140x1800= 252,000 +60,000 basement 312,000 +40,000 move-in ready. 50,000 incidental construction costs Etc. 200,000 is not realistic. Regards

140x1800= 252,000 +60,000 basement 312,000 +40,000 ready to move in. 50,000 incidental construction costs etc. 200,000 is not realistic. Regards

The OP is at a minimum of €2000 per sqm for the fittings.

1800 euros per sqm already ege

Regarding the equipment, the OP is at a minimum of 2000€ per sqm

and the own effort, which the actual question referred to? How much can I deduct here or would be possible?