"Mike" wrote in message
...
"brugnospamsia" wrote

Dear group,

My home improvement programme is in danger of being held up due to
conflicting advice I have received regarding how to attach
insulated plaster
boards to 9 inch solid brick walls built with lime mortar.

Brent borough council insist on battening and hence a generous air
gap over
brickwork with no waterproofing treatment applied directly to the
wall :-


http://www.brent.gov.uk/bccs.nsf/248...944/bda0a799ca
60698c80256c1d0047621d/$FILE/BCCS%20Dry%20lining%20Solid%20Blockwork%20info%
20sheet%20No.7.doc

A video made 10 years ago by a local university shows waterproof
sand/cement
render being applied then the insulating boards attached with
adhesive dabs,
the boards then being skimmed.

The outside of the wall is rendered and I don't appear to have
problems with
penetrating damp


If your wall had been unrendered life would be much easier. You could
simply use a vapour barrier, PB and rockwool.

Unfortunately unDPCed solid walls should not be rendered on both
sides, nor vapour barriered on both sides, since damp will slowly
accumulate in the wall, and have nowhere to go. Injection DPCs do not
solve the problem.

Since youre already cement rendered on one side, you dont want to be
attaching any form of vapour barrier to he inside.

Yet if you use PB and glass wool, a vapour barrier you would need.


The possible solutions?

A. Remove external render, with real care to avoid damage, then
proceed with vapour barrier internally. Dont cement render these old
buildings, it can damage them.

B. Apply expanded clay in lime plaster to the interior. This gives
insulation with no vapour barrier, retaining wall breathability, and
without the damage cement sometimes causes.

C. Do nothing.


Your idea of venting to the loft might work, I dont know. It would
make damp worse in winter, but then dry it in summer. But if you do
that you will lose out on insulation value, and I didnt see where in
your sketch the rockwool is going.

In principle I imagine you could install PB with vapour barrier and
pipe the trapped air to a micropower drying unit, never heard it
tried.


Knowledge on old houses has come on a lot in the last ten years.
Look at www.periodproperty.co.uk for a variety of articles on the subject.

hear hear


NT