On 14 Nov 2004 16:59:44 -0800, (N. Thornton) wrote:

(Jake) wrote in message ...
On 12 Nov 2004 17:42:45 -0800, (N. Thornton) wrote:

The plaster that's already on the walls inside, seems about as
absorbent as lime plaster.

How did you judge absorbency? I'm not sure how you can. Either it'll
lime or gypsum, clay plaster is most unlikely.


There's a party wall, perpendicular to the
damp side of the house which divides the lounge from the hall. In the
hall, the plaster is lime plaster, but in the lounge, the plaster is
some modern but similarly absorbent plaster.

modern plaster is not similarly absorbent.

Both felt equally damp to
the touch.

You cant judge moisture content by feel as far as I know, hence the
widespread use (and misuse) of damp meters.


I appreciate your comment about the rendering going down to the ground
outside preventing evaporation. It may be difficult to emove that, but
it would be easy to install absorbent air bricks,

Air bricks arent absorbant. Removing that render is the one big
effective thing to do, but really only if you can do it without
damaging the very soft bricks underneath. If not, you could at least
cut through it gently over the mortar joints and expose those. The
remaining render will fall off one day, but will take years to loosen
its hold, sometimes a lot of years.


say every six feet,
close to ground level. But drying out the exterior skin of the cavity
wall isn't really going to cure the rising damp in the inside skin, is
it?

It would, if you had rising damp. Swapping the saturated cavity air
for fresh would reduce the RH in the cavity air, thuse permitting
evaporation from both skins. But what looks like rising damp is
normally not rising damp. Rising damp is far from common, it is now
realised that it has been very overdiagnosed, and often still is.


I could install some absorbent airbricks in the inside skin, below the
level of the suspended floor.

Hang on, are you saying you have a cavity wall, timber suspended
floor, and no airbricks? If so, something is wrong there. And will
need putting right before the floor structure rots. People have been
known to render over airbricks before!

Actually, come to think of it, I did see airbricks below floor level,
but didn't notice how many.

I'm not sue how many to install.... one
every four feet or so perhaps. When the holes for the air bricks are
cut, I can also clear out any debris in the cavity hopefully. A lot of
air bricks will obviously detract from the thermal insulation of the
cavities, but if it cures the damp, I'd be likely to go for it...

Jake

Jake, I'm going to be absolutely straight with you, you dont
understand what youre doing, and need to learn.

That's why I'm seeking advice here. :-)

Otherwise youre
thrashing about in the dark, doing work that doesnt need doing and
wont wotk anyway. Its not difficult to learn, really its not. Try
these guys:
http://www.periodproperty.co.uk/cgi-...sing/forum2.pl
they'll take you through it bit by bit, then you can apply true
expertise to your house.

Thank you for the suggestion. I'll see what they say. Thanks for the
other suggestions too.

Jake