Floor plan draft for a 220m² single-family house

That means the budget would be exhausted without a reserve, and now the planned has to be cut back so that the unplanned can have "space" again?

I hadn’t counted on that either, otherwise I would have already hit the brakes somewhere beforehand.

I could have told you that right away – you based your calculations on false assumptions: you mentally did not include the non-living-area square meters (garage, basement, partially credited terrace areas) – and also that even without complicated beams, the cubic meter of sculpture is more expensive than the cubic meter of box with the same tiles and sockets.

The smaller garage is a valuable approach, the kitchen bay window as well, but a cheaper oven is probably a wrong place to save. And you will regret the omitted brick slips areas, or with their substitution by color surfaces you will again get exactly the similarity to Müllermeierschulze’s house that you wanted to avoid.

Nicer tile - bam, more sockets - bam, more light - bam. Every time you need more than the standard.

For the flooring, we have specifically budgeted for 125m². That is the budget, and we have to live with it. Period.

For the sockets, we can only have a few extra sockets compared to the construction service description. We don't have high demands there. Currently, €10,000 electrician budget is planned. That will be tight. I haven't done a detailed plan yet, as it doesn't make sense if 100% of the final floor plan is not fixed.

Thought about curtains, lamps, furniture, carpets or similar?

We don't want curtains. I will have the lamps calculated, to see how the ceiling spots work out. We are taking the furniture with us and might gradually get some more if needed. We won't have carpets; that's not our thing.

I want to have about €50,000 cushion for the mentioned contingencies. And apart from the €10,000 for the electrics, that should cover the items well. Higher quality room doors are already planned, higher quality security technology for windows and doors... and other things... of course some things might be added; but some things might also be omitted.

Sorry, please don't be offended, but I always get the feeling that you don't really have an overview of the matter because you don't seriously engage with it yourself.

I deal with the whole thing day and night. But I lack routine and confidence, and therefore I want to have a construction supervisor at hand. I wouldn't call it delegating; more like doing your homework. I don't think that I engage too little with it, but indeed I lose the overview when I have to deal with a thousand fronts at the same time....

So that means the budget would be exhausted without a reserve, and now the planned items have to be cut back so that the unplanned items have "space" again?

There is still a 20,000 EUR reserve. Otherwise, it is exhausted.

However, we also knew that we were somewhat groping in the dark cost-wise and had the kitchen bay window planned only as an option. That can be quickly removed again and saves €10,000.

Further savings potentials:
- Floor covering in the basement calculated at €75 / m². My parents also simply have concrete in their pantry rooms in an otherwise nice house.

- The desired high-quality room doors were also planned in the basement; that makes no sense.

- We might do the water softening system later or skip it; it is not a must-have.

- For the flooring, we also have to see if €125 / m² is really needed for the ground floor and upper floor.

- The security technology for windows in parts of the upper floor might not be necessary. Only for burglars who climb a ladder.

- The house surrounding work, calculated at €55,000, might not have to be fully spent immediately, and parts of the outdoor facilities can be established later; THAT is, for example, a point that makes sense to discuss with a building consultant.

Leaving things out for now that can be quickly caught up later would not be a problem. We receive about €20,000 additional liquidity per year that we can invest in the house.

the desired high-quality interior doors have also been planned through the basement; that's nonsense

If it is a purely utility basement I agree, if it is an extension of living space I would keep the doors.

My parents also simply have concrete in their otherwise nice house's storage rooms.

There are also inexpensive tiles, which should be sufficient for such rooms and are probably "better" than concrete.

even with the floor covering you have to see whether you really need €125 / m² for the ground floor and upper floor

Is the €125 only for material or including installation?

the security technology for windows in parts of the upper floor may not be necessary. just for the burglar who climbs a ladder

I agree with you, RC1 is usually sufficient on the upper floor.

the house surroundings work calculated at €55,000 may not have to be spent all at once

Terrace, driveway, access to the house, quite a bit of money goes there quickly without even a shrub being planted.

Are the 125 € just for materials or including installation?

Including installation.

I spent two hours with the construction consultant. He estimates that you can easily add another 70-80,000 euros to the listed price. That would be too expensive.

He advised against commissioning such a design with so little buffer. I saw it similarly, although I would have estimated the difference at around 40,000 €.

I want to have about €50,000 leeway for the mentioned eventualities.

You should plan significantly more for eventualities. Given the large area and the substantial building volume, 5% for eventualities (after deducting the expected higher costs for electrical work) is very tight. You are just at the very beginning and still operating on a high level of uncertainty. The 50k can melt like snow in the sun. You don’t have any concrete offers yet, and the workload of construction companies / craftsmen around Cologne is still very high. Out of 10 inquiries, 8 are not answered at all because the order books are fully booked for at least 6 months... And those that do respond, quote exorbitant prices. It takes a long time to find a healthy price-performance ratio.