Must the construction company itemize the costs per trade?

Hello everyone,

we are about to build a city villa measuring 10m x 10m with a single-story bay window at the back measuring 4x1 meters. However, in the upper floor (OG), it remains 10x10m without the bay window. Now we have extended the bay window down to the lower edge of the house to 6 meters. This means the walls in the upper floor no longer stand on the lower walls in the basement (UG). This has added 2.9 m² of living space, and the construction company wants 11,800 EUR more for that. That is about 4,000 EUR/m². The roof of the bay window is not even included here.

That’s not normal, right? Of course, it affects many trades, but not in total. Most of the costs come from the base slab, screed, reinforced concrete ceiling to the upper floor (which has to be made more stable). Is the construction company trying to rip me off? They have tried that a few times before, but I was always able to prove that it was not the case, which they always acknowledged.

Attached is the planning before and after.

Do I have to ask the construction company to list the costs by trade if I ask for it?

Thank you in advance for your feedback!

Best regards

It sounds like you already have an existing contractual relationship with the construction company? Possibly also with the "Vorher"-floor plan as an annex to the contract?

How far along is the planning or construction already? Does the structural engineering possibly need to be recalculated here? Does the energy saving certificate need to be newly created?

I can imagine that the structural engineering will become significantly more complex because there are considerably more upper floor exterior walls without ground floor walls underneath. Perhaps suddenly a steel beam in the ceiling is necessary here where it was still possible without one with a small bay window.

Ultimately, the construction company can charge what they think is appropriate. In case of doubt, it is a defense price because they have no desire and time. And I don't think they have to break that down for you.

Yes, we already have a contractual relationship with the contractor based on the previous planning. Structural engineering etc. also needs to be newly created, but there are an additional 600 EUR costs that cover this. I didn't even mention them. We also have to submit the amendment for the exemption, but since it is an exemption, I don't think it's a problem. Construction start would be mid-March 2020, but we definitely want the new planning now. I just want to know if it is justified and if I should be at odds with the contractor, or if it doesn't make any difference anyway.

So the price is not justified?
Too bad, I thought there might be a law where they have to list the costs by trade.

Your house now also requires an enlarged foundation slab, even though you are not getting any more living space on the upper floor, so it becomes significantly more expensive per square meter. You will probably need a large steel beam to support the walls on the upper floor.

Best regards
Sabine

The price seems reasonable to me. There is extra effort for the planning changes, materials, logistics, and labor time. The price per square meter for the house will be roughly estimated to increase by €30. Calculating the price per square meter only for the bay window (complex) and comparing it with the mixed price per square meter of the house is really funny. With such a calculation, you are pulling one over on your counterpart, not the other way around.

I just want to know if it is justified and whether I should be at war with the construction company, or if it won’t bring anything anyway.

What it will probably bring above all is a sour relationship with the construction company, with whom you will have a fairly stressful time in the coming months. I think starting off with such a negative attitude is a bad idea.

Have you simply asked the construction company how the price is composed?

So the price is not justified?

I can imagine that the price is justified.

Too bad, I thought there might be some law requiring them to list the costs per trade.

And what if it turns out that they book half of the costs under items like "Good order situation," "Bad weather, would have preferred to call it a day," or "Site manager anyway prefers the small bay window"? Unfortunately, you can't change the costs either.