Rough cost of adding a room on top of a garage...

[NewChapter22]

Hello, considering putting an offer on a house but main selling point for me is the possibility of adding a room on top of the existing garage as it doesn't currently have enough space. Can anyone please tell me how much this will cost roughly (based on recent experience!)? I am attaching here a drawing showing the additional planned bedroom in yellow. Thanks in advance!

I can't advise on a cost but the important thing at this point is the depth of the foundations for the garage and if this would take the weight to be built on.

It's very unlikely that you can just build on top as the footings are probably not deep enough. So you would probably need to demolish it and then build a two storey extension in it's place. The cost depends on where you live and the finish really. You probably need planning etc. too. It won't be cheap.

What others have said. Here in south west this would be approx 60k

Thanks, I was just reading up on the foundation issue! Not as straight forward as I thought then and not sure if financially viable if it will cost £60k+. Converting the existing garage is probably an easier option!