From the chaotic regions of the Cryptosphere, Dan delaMare-Lyon
wrote on Fri, 08 Aug 2003 13:19:33 GMT:

I'm about to start sketching some ideas for our extension so that I
can go to the building control officers for an informal chat (now that
they do these things for free) before we get plans drawn up proper.

It may be that you don't need planning permission, if you've had no
other extensions and the volume of your new extension is not massive
or closer to the road than the house.

Masonry cavity construction is the most common form of building, so
your BCO may want calculations for a timber framed structure.

The minimum cavity masonry wall thickness that will comply with the
thermal insulation requirements is 265mm- Outer leaf of brick, stone,
etc.; 65mm cavity with full-fill mineral fibre batts; and an inner
leaf of very lightweight aerated concrete block (Durox, Celcon Solar,
Thermalite Turbo. Have a look at insulation or block manufacturer's
websites (http://www.aircrete.co.uk/ ,
http://www.rockwool.co.uk/sw7050.asp, http://www.celotex.co.uk/)
--
Hugo Nebula
"You know, I'd rather see this on TV,
Tones it down" - Laurie Anderson