Incorrectly calculated house area

Hello,

I wanted to completely insulate and board up my old house. It is quite large and intricate.

I sent the construction plans to company X and had them prepare an offer for me. After I gave the go-ahead, the head of the insulation company came and measured the entire house.

Now that one side of the house is insulated, I notice that 100m² were calculated too few. He had calculated 240m² but it is actually 340m²!

Of course, there is only material for 240m².

The purchase contract for the material naturally only states the quantity calculated for 240m², as do the labor costs, since I relied on the calculation.

What can I do about this?
Do I now have to pay again for the remaining 100m²?
Or does the insulation company have to cover this since they made some kind of miscalculation?
Thank you in advance for your help.
Regards, Sven

Hello Sven,

Do I have to pay again for the remaining 100m²?

Yes.

Or does the insulation company have to cover it since they calculated something incorrectly?

No.

People are involved everywhere and nobody is free from mistakes, so why should the company give you material worth 100 m² including labor for free? Talk to the person you gave the order to. If he is still around he will surely make a concession on the price – however, you have no claim to that.

Kind regards