Cost of building a garage and a room+ensuite above

[haylooo]

Hi guys

I'm thinking of putting in an offer for a detached house that has an old garage and thinking of ways of building more rooms to it as it only has 3 bedrooms and 1 bathroom at the moment.

We are in South West London, how much should we expect to pay for a very basic garage (no decoration inside, just brick finish) and a large bedroom above with ensuite? I think the floor area will be about 3.5m x 7m. Hoping that I can cut cost by keeping the cost of decorating garage to minimum - I will probably just leave it without any insulation just brickwork inside and out and nothing else to it, and just one light. The bedroom will need proper insulation and decoration as usual.

Would it be cheaper to just convert the loft of the same size?

Please help!

Thanks
H

I can’t give you an exact figure I’m afraid (we’re doing the same as you suggest but along with substantial other work too).

However, as the original garage would need to be demolished and new foundations built (due to the second floor being added) this will be significantly more expensive than just an attic conversion.

For a similar build in a much cheaper area to you I’d expect to pay about £80k for what is a double story extension. The inside of the garage is probably a negligible expense in comparison to the footings and general work to get utilities in to the upper levels.

Building Regulations would require you to demolish it and rebuild if it doesn't have sufficient foundations to support a second floor. You'd also have to have enough insulation in the walls downstairs for it to be signed off.

I agree with the above. We paid around £2k per sqm for a basic finish, additional for upgrades so you will probably be looking at £80k plus.

Is the garage a seperate building away from the main house or attached on the side/back etc? Will it be more of a bedsit or part of the main house?

We did quotes for similar and it was £75k plus VAT plus £2k plus VAT demolition costs for old garage