Expand prefabricated house?

Hello, we have now viewed the house. The view and location are good, it is very well maintained but there is a catch: there is one room too few. Now we came up with the idea, if the price goes down a bit more, or is negotiated, to expand the house by one room, and to build a basement room underneath this extended little room, since it has no basement. What do you think? Would that be feasible or is it more uneconomical, since the costs for such a project would be immense. Best regards

Do you know which provider the house is from? If yes, does it still exist? Because our provider offers the option of extension. They seem to regularly expand their old buildings. But the company has also been around for 60 years.

If you know the provider, they can probably best tell you if something like that is possible, keyword statics, and what it will cost. It certainly won't be cheap.

Hello there, it is an Okal house. I already called there, but in the end, I was just as clueless as before.