John Rumm wrote in message ...
Jake wrote:

Does anyone know if silicone injection damp-proofing is effective? I
have what appears to be rising damp along the two walls of a room in

It is probably effective in the sense that it will introduce a damp
proof layer in a wall. However whether that will cure your problem is a
very different question. It would depend on why it is damp.

my 1900-built house. (The damp can be detected up to about 4 feet

Detected how? Have you drilled samples and tested for moisture content
in the removed material, or just used an electrical resistance tester?

above the floor). I suppose it could also be damp penetrating through

The most common causes are "bridging" (i.e. soil/path level above DPC),
broken down pipes/gutters etc. Lack of heating and ventilation (blocked
air bricks, fitting DG windows and hence eliminating natural
ventilation) inside the building and hence condensation.

from the outside skin of the cavity wall, if the cavity has some
debris in it. Due to the 104-yr old age of the house, I guess it was
built with a slate damp-prroof course if anything. Would silicone
injection likely cure it - and if so, how long for?

It could well be a solid wall at that age. A slate layer would be a
typical DPC for that age. Assuming there are not extensive cracks in the
wall, how exactly does a bit of slate "fail". Does it cease to be slate?
There is a possibility (although unlikely) that no DPC was ever
installed, in which case adding one may help.

If it is effective, can anyone ecommend a cost-effective place to hire
the gear from and where to buy the liquid? Any tips on actual
application?

Can't help you there - although I am sure the kit can be hired, and it
will presumably work out much cheaper than getting a damp proofing
company in to do the work.

--
Cheers,

John.


I would caution the OP about this path of action. 1900 houses handle
damp entirely differently from modern buildings, and dpc injection can
result in the fabric of the building beginning to disintegrate near
ground level. It is not suitable for Victorian buildings.

Nor is it effective in such buildings, it hinders the damp control
system more than it helps it. It seems to me you need to understand
how your building deals with damp, and what things you can rectify. To
speak with the experts, I'd suggest:
http://www.periodproperty.co.uk/cgi-...rum2.pl?#34641


For other general interest, most Vic houses had no dpc of any kind,
and there are indeed 9" thick cavity walls, its called ratbond. Vics
with dpc usually used slate as the dpc material, and slate dpcs often
become ineffective due to them being bridged on the outside with
mortar. Of the few slate dpcs I've seen at least half were bridged by
inappropriate repointing technique. However if this has been done, one
should be wary of breaking the mortar off, since cement in sound
condition is a lot stronger than slate.


NT