Extension costs ex foundation and walls...

[hamazz]

looking for a rough m2 cost of building a double storey side extension to a property in london.
neighbour already has 2 storey extension with wall built astride boundary line in solid 215mm blockwork. so we would not need to have foundations dug or walls built, we can use this existing wall.
guess mainly we would need floor joists for grounds floor ceiling and first floor, + ply flooring, insulation and plasterboard. the one thing i know will cost is breaking out the existing garage tarmac area and removing it to install a new concrete slab. or if someone can give a rough cost per m2, for concrete slab to include concrete, screed, dpm, insulation etc. and a rough cost for timber, joists/ply


size of extension would be about 2.4m wide *12m long * 2 floors.



hamazz

 

[joinerjohn]

What makes you think , you can just use the neighbours external wall as a constructional part of your extension??

 

[RonnyRaygun]

What makes you think , you can just use the neighbours external wall as a constructional part of your extension??

If the wall is built astride the boundary line then the OP has every right to use it, although they will have to pay their neighbour half the cost of building it for the privilege.

 

[hamazz]

well it was part of agreement before they got their planning permission, and they were happy with it, because they would get an extra 10cm width in their side extension. and its all built up already, and they have not asked for anything

hamazz