ᐅ Cost Estimate for Building an Extension

Hello,

while searching for a property that suits my classic car hobby, I came across a house with an outbuilding. The outbuilding was apparently used as a tractor garage or something similar and has the size of a small two-story house. However, the ground floor layout is somewhat cramped, allowing space for only two cars.

The outbuilding stands freely on a sufficiently large plot, so I am optimistic that I could get approval for an extension. I would like to build a hall/garage of about 200m² (2,150 sq ft) attached to it. The dimensions would be roughly 10 x 20m (33 x 66 ft), and I would like to do the masonry work myself. The interior would be empty except for a few windows around the outside — nothing else. I will handle the electrical work myself, as I am a professional in that area. Water is not needed. However, I am thinking of a pitched roof to match the existing outbuilding.

What would a project like this roughly cost? I know it depends on many factors, but I would just like a ballpark figure.

Why not simply demolish the old tractor garage and build a hall instead? Prefabricated halls are available at a fixed price. Just try searching online—I can’t share links here, but I just tried it with a search engine and immediately found a supplier for workshop halls.