ᐅ Is it possible to build an extension using prefabricated walls? How is it done and who carries out this work?

Hello everyone,

A few years ago, I took over my grandparents’ house. What I have never liked about it is that there is no proper bathroom solution. The main bathroom is in the basement and is difficult to heat (the house was built in 1954).
On the ground floor, there is a guest toilet that I am now planning to expand. The guest toilet shares a wall with a large terrace on the outside, so an extension of about 3 x 4 meters (10 x 13 feet) would fit well there.
My idea was to use prefabricated wall elements for the necessary walls. This brings me to the question: Are there companies that offer custom solutions for this? Or does the forum have other suggestions? What should I keep in mind?

Best regards

Fonsy schrieb:
an extension measuring 3 x 4 meters (10 x 13 feet)

... you will hardly find a prefabricated company for that; realistically, there is only one solution for you: find a local architect to design your bathroom, and then look for a company to build it... and what construction costs have you estimated for this?