In message , The Natural
Philosopher writes
Tony Bryer wrote:
On Sun, 5 Mar 2006 19:03:02 -0330 Terry wrote :
These commonly have 2 by 4 or 2 by 6 wood stud walls which are
heavily insulated.
Particularly on the latter do you not get problems with the studs
acting as cold bridges and causing pattern staining?



Cold bridges yes, pattern staining no.

However if enough insulation is used, the overall U values are good
enough for the regs.

I had in mind to leave part of the studs visible so staining is not an
issue. The most convenient place for the membrane is between the frame
and the outer insulation. I suppose it would be easy to leave an air gap
behind the boarding. Feather edge is not *airtight*anyway.

The structure would be studs infilled with plasterboard and 25mm
insulation, vapour membrane, 25/50mm exterior insulation, battens (long
screws:-) and feather edge.

This totals around 200mm so fits the architects idea of 9" supporting
brick but means any *nice* brickwork being hidden behind internal
insulation. I'm inclined to do cavity work and put a shelf along the top
to hide the ledge. Somebody will perhaps advise on closing the cavity:-)

Meanwhile I'm off to search the farm for bits of discarded Oak to
replace that rotted by the previous owners ignorance of ventilation.

regards

--
Tim Lamb