Wrong foundation with high consequential costs

Company B charges 6 hours per fitter to determine that the foundations are not correct? Sorry, but the very first thing the foreman does after getting out of the car is to measure the foundations. Then he knows whether he can build the carport or not.

If they decide to try it anyway, that’s their problem, not yours. The carport builders are the experts and therefore have to be able to assess whether it makes sense or not. If it doesn't make sense, it’s botched work, just like from contractor A, and you don’t have to pay for it.

Whether it’s worth getting something from company A... if at all, only in a few years, until then you have to manage without a carport and pre-finance your lawyer. If company A decides to go bankrupt in the meantime, the money is gone, including the money for the lawyer.

Could you take the measurements of the carport? Tip for next time: after finishing the work, measure yourself roughly whether it’s correct, meaning accurate to the centimeter, not millimeter.

I also trusted my excavation contractor and now have leaking rain pipes underground... Never trust a craftsman blindly...

Hello,

what amounts are we now talking about for B and A that have to be paid extra?

If A has no liability insurance, I would at least not pay anything and wait to see what happens. But not that they come up with something outrageous^^

So does that mean the company is liable with its own assets because no insurance can cover it?

But only regarding the correct construction of the foundations, or also for the additional costs incurred?

I don't know what problem you have with the 6 hours. The company scheduled the appointment for that day and then couldn't work. Driving spontaneously to another construction site is not possible; that also has to be prepared and announced. The damage is not the two hours in the car, the damage is a working day. And such installation teams rarely have work in the workshop that they can do on such days.

Liability with private assets only applies with the appropriate legal form. Most operate as GmbH, where liability is correspondingly limited. That’s also why the question about insolvency arises; with an insolvent GmbH, you can save yourself the lawsuit.
Liability also extends to consequential damages. The company will of course try to minimize these, so you absolutely need equal footing.