New window lintels on the ground floor are too low.

Dear forum members, I am new here and am reaching out to you with a question. I do not want any blame assignments, but if possible helpful tips. We are currently in the construction phase – a contract for a turnkey single-family house – and our little house is already standing. The windows are installed, electrical work is done, the external insulation + facade are applied, and the interior plaster in Q3 is also already completed. As a note, we are absolute laymen in construction and rely on the information from the house building company or the site manager. We have always dutifully approached them whenever there were things we wanted to "complain" about. Some things were done, others are still open, and other issues were just smiled away. Now somehow no one is smiling anymore... Over the weekend we measured a few things with a friend who is a professional, and we are, how shall I put it politely, somewhat irritated. All window lintels (this concerns two windows on one gable and 2 windows, one each to the right and left of the front door) on the ground floor are installed about 20 cm too low. Apparently, the lintel measurement was taken by the shell builder from the floor slab and the floor construction (screed, underfloor heating, tiles) was not taken into account. The construction company has now been informed and there will be an on-site inspection. It is undisputed that the (serious) defect exists. It is also clear to us that the house will not be "torn down" again. It also seems clear that the construction company must somehow rectify the building defect. Since demolition and structural changes (window removal, raising the lintel, new exterior facade, new interior plaster, etc.) certainly do not come into question, in our opinion only a financial compensation remains. We are aware that we can withhold the final payment. The question is, how high do you estimate the retention amount / pressure surcharge? What does such a repair usually cost, which factor can we apply? It is not about the "last euro," a rough estimate with numbers would already be very helpful. I look forward to your comments and well-founded answers.

What is the height of the lintels from the raw floor and how many cm of floor build-up do you have? The window elements are already installed? Nobody noticed that?! Are there shutters? That's really something... what passage height do you have in the floor-to-ceiling elements?

What is the height of the lintels from the raw floor and how many cm of floor buildup do you have? Are the window elements already installed? No one noticed that?! Are there roller shutters? That’s really something... what passage height do you have in the floor-to-ceiling elements?

Yes, the window elements are already installed, roller shutters are also available. I don’t have the measurement from the raw floor on hand right now. The lintel height of the windows is now 195 cm and tiles will be added on top. The floor-to-ceiling elements are at 220 cm. The measurements fit.

And didn't you notice that the windows had different heights? During installation, it should have been noticed that the distance to the ceiling is greater at the windows. You should be able to see 20 cm with the naked eye. But I wouldn't have it corrected anymore either. But I don't think there will be that much.

How many elements does it affect? The floor-to-ceiling windows are dimensioned correctly - only the "normal" windows are not.

How many elements does it concern? The floor-to-ceiling ones are measured correctly - only the "normal" windows are not.

It concerns 4 elements / "normal" windows. Correct, the floor-to-ceiling ones are measured correctly.