"BigWallop" wrote in message
. uk...

"Doctor Evil" wrote in message
...

"Lawrence Zarb" wrote in message
news:ab311db328d41a2c533c3e11bd589a01.52329@mygate .mailgate.org...

does anyone know of a good on-line site giving details of how to
construct cavity walls

Why? Why build two walls when one can do. There is nothing in the regs
that says cavity walls "have" to be built. The Germans think we are
mad.
Build one strong skin and use the rest of the space taken up by the
other
skin for insulation to drop your heating bills substantially. Don't
just
do
what the other dickheads do. Think!

But make sure you allow for a moisture barrier between the skins or layers
of the wall, or you'll end up with dampness creeping through the outer
skin
/ layer and in to your internal skin / layer.

And make sure the outer skin is waterproof, as with all walls.

A ventilated cavity is a simple method to prevent this from happening.
Funnily, this is a method also used by the others that laugh at us, so is
pretty well a universal method of preventing moisture ingress through a
buildings outer skins and insulating materials.

Cavities are not universal. Only in coastal wind blown regions are cavities
used and the they use render on the outside to seal in the walls; Cornwall,
Brittany, etc.