John / All

My responses are in-line

John Rumm wrote in message ...
Clive Long,UK wrote:

To summarise what I have found.

The wall is 7.60m long, 2.35m high. It is a "shared" (with adjacent
flat) internal wall, probably load bearing as concrete lintels cross

Do you know what is the other side of the wall? (for example a bathroom,
a radiator, aquarium ;-) ?


On the other side is another narrow hallway with no furniture nor
radiator. The flats are "mirror image".


Question: Could the high conductance be due to damp wall-paper rather
than the plaster?

Well it can be - those meters can be rather notorious for measuring all
sorts of unexpected things if you don't pay attention to how you are
using it (i.e. conductive wallpaper, surface moisture, cinder block
(i.e. high carbon) wall construction). They were originally designed for
making measurements in timber - for which they are quite accurate -
hence your comment about a high moisture content on the skirting would
seem to indicate more than just surface moisture.

Well the wall I think is this "high carbon" material covered with
plaster skim. When I have drilled into it in the past it is a black
material that disintegrates when assaulted by a hammer drill. However,
the depth I am pushing in the probes of the Protimeter make me feel I
am only measuring conductance through damp plaster.



Initial thoughts

1. The radiator is causing the problem. But how? And what to do? I
can't move the rad.

The radiator itself may not be a problem - you would probably see water
dripping / spraying out if it was leaking - possibly even rusty water
stains, but where do the pipes go?

For example, a set of pipes buried in the concrete floor can be a soggy
mess waiting to happen if the pipes were not adequately protected before
being concreted over.

The radiator is on the OPPOSITE wall to where the damp is - I did not
make this clear. Also all pipes are "surface mounted" on the skirting
and not leaking.
The reason I mentioned the radiator is that the Oxley book gives a
scenario where hot "moist" air from a radiator rises then moves across
the ceiling, cools, drops down the opposite wall, cools more until the
wall temperature is dew point and the moisture in the air condenses
into the porous plaster.


2. Damp is coming from the floor. How do I investigate that further?


Short of drilling a hole and analysing the water content of the dust
removed by the drill - tricky.

But maybe if I lift the carpet and underlay, and some vinyl tiles. If
there is an obvious source of damp the underlay should be damp at this
point - and I can try to measure the dampness of the concrete screed.
Thoughts ???


Any ideas on what to investigate next to try to isolate the problem
before I call someone in who may attempt the wrong treatment because
they haven't understood the cause ?

Look for the obvious causes first. So called "rising damp" is very rare
in reality - almost unheard of in modern building materials. Penetrating
dampness from the other side of the wall is far more likely. So check
that with the neighbour (also finding out if they have the same problem
(or a less or more severe version of it) would help. See if you can
trace where the radiator pipes go as well.


I have tried getting access to the neighbours property on 3 occasions.
He just says he doesn't have a damp problem and won't let me in to
measure. There are other issues around not getting access not related
to investigating damp. If I can get a solution to the "damp /
condensation" problem that then puts him in a position where he has to
be more co-operative - then that will be a satisfactory outcome. I
won't do anything that will deliberately cause a problem for him.

As mentioned above, routing of radiator pipes is not an issue as they
are all surface mounted.

I'm happy to pay a professional to cure the problem - but I need it
properly diagnosed. I get the impression that a lot of the
"Professionals" are quite the opposite - which is why I am performing
the initial investigation myself and I will be in a better position to
ask "why?".

--
Cheers,

John.