Possible cost overrun

Dear house building team, Unfortunately, we have decided to build with an architect. After the tenders, he presented us with a cost estimate. This was significantly higher than the cost calculation. Now we are concerned whether the construction could become significantly more expensive again. Does anyone of you have experience with this issue? Actually, we think that if the offers have been obtained, we have a price guarantee, right? Best regards Ann Sophie

Actually, we think that once the offers have been received, we have a price guarantee, right?

Nope, during the course of the construction, there will surely be additional special requests that weren’t considered or the specification won’t completely fit and amendments will be necessary. There is no price guarantee.

What is a cost estimate?

The offers will explicitly refer to the [Ausschreibung]. Any extra request etc. will cost...

Why has it become so much more expensive? Do you have details? Have them break it down for you.

Does anyone of you have experience with this topic?
Actually, we think that once the offers have been obtained, we have a price guarantee, right?

If the architect hasn't forgotten anything and no new ideas come up during the construction, then the price will remain.
If the bid really is significantly (by how many percent?) above the cost estimate, the architect has messed up and you could (at least theoretically) hold him liable.

If the architect has not forgotten anything and no new ideas come up during construction, then the price remains.

Really? An estimate only means that preliminary cost estimates are available. It does not mean that there are absolutely fixed prices.