Andy Hall wrote:

On Sun, 5 Oct 2003 22:15:28 +0000 (UTC), "Richard"
wrote:


Me again,
Thinking of buying a Victorian semi - haven't seen the struct survey yet but
says there is indications of rising damp in the party wall.
Presumably this requires a new DPC - easy enough in MY side, but what about
the neighbour's? If a new dpc is laid on only one side will it be as
effective?


I think that you need more information before jumping to conclusions.

From my own experiences and those of friends concerning properties of
this age, "rising damp" tends to be more of a label given by surveyors
and others to cover a multitude of damp wall conditions.

It is fairly rare that there is dampness on party walls away from the
exterior walls, so I would ask the surveyor to be more explicit about
the exact location.



Not so. It can be fairly common.

When I bought my old cottage, it had been injected on the exteriors
walls, and *some* of the interior walls as far as could be done..BUT in
one case an interior wll containged a huge chimney stack, and wjhen we
finally demoilished teh house, that while area (raised wood floors)
teurned out to have essentially a pond underneath it. Massive amounts of
water would soak upo through teh bricks of the hearth into the walls.

It was the expense of underpeinning and DP'ing that stack that was the
reason for a drastic rebuild as much as anything..that and the discovery
of massive rot in the structural timbers due to rising damp, as well.

If the house does not have solid floors, the potental for underfloor
water and dampness is huge. Ok you CAN help by digging a french drain
around it to lower the local water table, and control with central
heating, and myabe an underfloor sump and pump, but rising damp on
internal walls is a big problem.

Injection will fix it, if there is space below the floor boards. And no
huge chminey/hearth in it. Your neighbour should share costs. Laying
solid concrete floors over DPM is also indicated.



It's also fairly rare for moisture to soak up through the brickwork,
the DPC having failed. In properties of this age, the DPC was
usually slate.



Or non existent.


What is far more common is that the ground level outside has become
built up over the years with the addition of soil or perhaps concrete
and the DPC has been bridged. If it's by a couple of courses of
brick there can be a fair amount of water penetration through the
brickwork.


Unlikely inside the house - this is NOT an external wall is it?



Another common issue is faulty guttering or downpipes leading to water
running down the wall when it rains. If you consider that in
semidetached properties that there is often a rainwater downpipe at
the boundary taking water from the main roof and perhaps bay windows,
then a failure will result in dampness at the party wall as well.



Possible.


These points should be checked before embarking on more draconian
treatment. What often happens is that a damp company comes along and
does an injection DPC and while doing so lowers the ground outside
perhaps to open up air bricks. The damp problem is cured, but could
have been done just by lowering the ground.

You would also need to know about the construction of the party wall -
whether it is single or double brick thickness.

Ask the surveyor - that's what you are paying for. If he just
recommends calling in damp proofing company XYZ, check at Companies
House to see if he or his wife is a director.

Then also get several quotes and see whether the recommended treatment
varies.



How do you determine which side is causing the problem, and again what if
it's the neighbour's side?
Thanks in advance - again!
R



.andy

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