Increase knee wall height after building application - exorbitant additional costs?

Hello,

I will try to describe my case as briefly as possible.

We found and chose a property developer. Everything was planned so far, and the building application was submitted to the building authority last week.

Now we would like to increase the knee wall to 1.25m or 1.5m. The knee wall is planned and in the building application only 1.00m high.

I passed on our request to the developer today. So increase the knee wall height, keep the roof pitch the same at 45°.

He said it would cost us a whopping €6000!!! But only the building application has been submitted... how do they come up with such a high amount? They justify it with the following services...

- new thermal insulation certificate
- change to the building application
- quantity calculation

Does anyone have experience with this, is the amount justified?

Thanks in advance for reading and for informative answers.

Regards
Enrique

Would have said 1000€ now. But in the [Bauträger] system (probably more [GU] or [GÜ]) every change after contract signing has to be paid for.

Well, whoever comes too late is punished by life. Apart from the fact that it is actually much more effort than you think (the surveyor also has to change his site plan, print it out, fold it, stamp it, sign it, bring it to the planner, write the invoice ... ; ) you have no choice. Either you pay what he demands, or it stays as it is.

Hello, we have a relatively inexpensive BU. Planned is a bungalow of 140 sqm. I asked about increasing the knee wall by 25 cm. The additional cost was 3000 €. More masonry, facing bricks or clinker, insulation. Everything costs money. We did not do it because we did not want to convert the attic. All before the building permit. The second BU (relatively expensive) did not charge for the knee wall increase because he most likely calculated everything in the offer.

how do they come up with such a high amount?
They justify it with the following services...
- new thermal insulation certificate
- building application amendment
- quantity calculation

They really like you a lot, that's more of a special price for the effort. Additionally, there will be an exceptional permit, the granting of which I do not consider certain: 45° roof pitch and knee wall 1.50 m suspiciously sound like a full storey. Besides, this knee wall height practically only works if you limit yourself exclusively to gable windows.

Hello again,

thank you for your answers.
What Escroda wrote is probably the most accurate. "He who comes too late is punished by life."

I sat down with the developer again.
Fortunately, they came around a bit and the increase of the [Drempel] to 1.25m costs me "only" €4800.
(incl. [Wärmeschutznachweis], [Bauantragsänderung] and [Massen])

Thanks again for your time

‍♂️