How much is a tiny extension in London? Floor plan included

[Newhouse76]

I would like offer on a property which has a tiny kitchen 3 x 2 m which I would like to extend to still tiny but slightly larger as shown in the neighbouring house floorplan!

Does anyone have an approximate idea how much this could cost? There is no side access, it would need to be through the building.

Thank you!

I don’t know about cost of your extension, but family member has just costed up extending their home, and doing 2 stories did not add much

If you did that you’d have a nice 3rd bedroom (move sink & loo so can access off a hall) and the extra space is a ? Single bedroom, office, walk in closet or combo of these

My guesstimate is around 50k

It looks like about 7m2. Basic build costs are about £2k per sqm for a shell but you will have a lot of fixed costs on top of that for which you will not have an economy of scale. Maybe
£15-20k for shell and first fix
£2-4k windows depending on spec
£5k for second fix (more if you want ufh)
£3k planning, building regs, architects
£5 to £30k for kitchen depending on finish

That should be 35k for the shell. Kitchen costs could be £10-30k depending on what you choose