Wall thickness

[FraserM]

Hi
I want to build a small extension in a rectangular space at the corner of my house, effectively filling in the area with a ground floor utility room. The present back door opens onto this space. The trouble is I want to put in a washing machine and a dryer on the end wall, but when I take off the "normal" cavity wall dimension of 300mm, the internal space I end up with, (including dry lining plaster), will not allow these to be fitted. It is only a matter of about 10cm, but the builders I had round to estimate said "you have to have the 300mm cavity wall or you won't get Building Regs approval. Is there any way of building thinner cavity walls which still maintain the BR standards or have I got to go outside the back wall building line to get the space ? This latter would be very awkward as I would have to have one of the drains to the upstairs loos and shower diverted.

 

[^woody^]

Don't use those builders whatever your do

You can have a single skin brick wall (100mm) and 80mm of insulation and 15mm of plasterboard and skim

Or a 100mm timber frame, and exterior cladding

Or, (this depends on your layout) take off the external skin of your existing external wall (which will now be an internal wall) and this will get you 100mm or 150mm if a cavity wall. Put a lintel in higher up

 

[noseall]

I don't know about all authorities across the board, but 80mm will not satisfy our local bods.

125mm minimum and 140mm in certain locations.