Plaster bridging DPC behind skirting

[Lobster]

I'm suffering from some low-level damp at around ground level (both external cavity walls and internal walls); suspected a combination of condensation and rising damp. Having removed the skirtings, I find plaster right down to the level of the (solid) floor in many places, ie bridging the physical DPC, which is about 1" above floor level. (Why is it that every single time I have ever removed skirting boards, in any house I've ever owned, I always find this??!) I've just cut the plaster back above the DPC.

Question: is this likely to be sufficient to ultimately allow the walls to dry out properly, or am I wasting my time waiting - do I need to go the whole damp-treatment-company-reccomended hog and cut the plaster back to 1m high and replace with sand-cement instead?

Thanks David

[Rob Morley]

Surely cement render is an admission of failure to prevent the damp? If you've fixed the problem by removing the bridge then it should settle down eventually, if it doesn't you can always take further measures. ISTM that most damp treatment companies are only interested in selling their services without really understanding the problem.

[Dave Plowman (News)]

It certainly won't be doing any good. But I wonder if the DPC has failed in some way - given the plaster must have been there a long time?

In my Victorian house with no DPC, the 18" high skirting board has no plaster behind it at all - obviously installed before the plastering. I sort of assumed that the combination of a cellar - and the floor level being about 1 foot above ground level, then this 18" gap, prevented rising damp in the solid walls. Because there isn't any.

I thought this treatment was restricted to applications where a chemical DPC had been installed?

I know it's an obvious one, but you have checked that the ground level outside is at least a couple of courses below the DPC - and that the pointing is in good condition?

[Lobster]

Oh, maybe...

Yes re ground level; pointing isn't brilliant but I wouldn't have thought bad enough to allow water in; but anyway, the fact that the problem is no better or worse on the internal walls suggests it isn't penetrating damp I think.

Thanks David

[Dave Plowman (News)]

IMHO, poor pointing is a major cause of damp on external walls. Obviously not on internal walls, but then again rising damp is unusual too on those, because they've usually got several courses before it would show - and damp doesn't rise very far.

I'm not trying to teach granny, etc, but older houses were designed to have pretty thorough ventilation - open fires pulling air up through chimneys, and fairly leaky windows etc. Remove some or all of these and add in washing machines, regular showers etc and you'll get condensation - unless you keep the whole house pretty hot with heating that doesn't produce moisture.

Just a few thoughts for discussion.

[Lobster]

Sure; I do think there's likely to be a condensation issue - it was the fact that the problem is almost entirely restricted to the bottom 12-18" of the walls, internal and external, plus the plaster-bridging issue, which was worrying me. The place is quite well-ventilated - all rooms have large, fixed, open ventilators (think there were formerly gas fires throughout, so presumbly to comply with gas regs?) but it has been empty and unheated all winter. Reckon I'll leave things as they are now, and see how it goes.

Thanks Gran^H^H^H^H David