Translation:The house's foundation is not excellent.
It would be very strange to use 'foundation' (singular) to refer generally to the substructure of a building. These are really plural- foundations.
I disagree. At least in my part of the world, we would say "the foundation of the house" or "the house's foundation". Perhaps it's a regional thing?
Why is this sentence in this skill? Maybe it would fit better in a different one...
Is 'fundament' used when you mean a charitable foundation, or just for the substructure of a building?
As a native American English speaker, the translation makes no sense. One would never talk of a foundation as famous. The house might be famous or not but a foundation would only be discussed as part of the house.
Sorry for the split post. In this case we are not talking "famous" but "excellent" (fremragende). First, one would never speak of any construction as not perfect as there is always some defect in it, so it is always not perfect. Second, one would only speak of the foundation separate from the house if there is a specific problem with the foundation. But if there is a clear problem, it is the problem that would be stated. One would not say that the foundation is not perfect to identify a problem. One could say that the foundation is defective or has a problem, but not that it is not perfect.