Damp coming back after damp course

fatboyonadiet

Had a damp course done last year as we've started to get the hot weather this year there has been damp patched appearing above where the damp course finishes.

I ddi speak to the company that did it (it was guaranteed) and they said keep an eye on it if it gets worse, they said to me it's the moisture in the walls trying to escape.

Is this right? It has got slightly worse and I might call them back to investigate it but how is the problem stopped?

chnelomi

ok my knowledge of damp proofing is limited sure someone more knowledgeable will correct if i'm wrong.

Dose the damp course go higher than the ground level outside and what type of wall brick sandstone etc is their adequate ventilation.

Seems strange to me that the problem has taken a full year to arise suggesting the course may be ineffective or incorrectly done.

fatboyonadiet

It does go higher than ground level, at least 3/4 feet

The ventilation isn't brilliant with it being an old house but I did have an airbrick installed in the chimney breast wall, the damp has appeared at a different wall.

It seemed to be brought on buy a bout of very hot weather a month or so back.

chnelomi

sounds like in adequate ventilation, you may need more vents put in.
Worst case could be a break in the course but i'd go for vents first less hassle lol
Is it old plaster! if yes then the wall may very well be sweating and vents would definitely help,
Good luck

Doozergirl

fatboyonadiet wrote: »

It does go higher than ground level, at least 3/4 feet

The ventilation isn't brilliant with it being an old house but I did have an airbrick installed in the chimney breast wall, the damp has appeared at a different wall.

It seemed to be rbough on buy a bout of very hot weather a month or so back.

It won't go that high. They might hack off the plaster to the height of 1m (3 or 4 feet as you say) but the damp proof course itself will be seen as a line of drill holes outside. You need oto make sure that the ground outside is nowehere near that level.

DPC is rarely the solution I'd say for damp issues. It prevents rising damp - that is smoething i have only seen once yet every house I've ever bought has had a DPC recommended including the one I live in, which has no issues to speak of.

There's usually a root cause and it's usually above ground level. What is on the other side of that wall? Whatever is causing it, it isn't a dry spell!

I have to say that my sister in law was going mental about her failed new damp proof course. It turned out that the problem was that the overflow hadn't been fitted on the bath properly upstairs, manifesting itself downstairs. I said when I saw it that it wasn't the DPC, I could just tell

fatboyonadiet

Apart from the re-plaster after the DPC the rest of the plaster is old

The wall with the damp patches is an internal wall, the other side of it is just the cupboard that runs under the stairs, no visible issues on the other side

Don't think the ground outside is anywhere near the holes, the whole room and outside are level

Doozergirl

I know exactly what you're talking about.

Have you vented it? Did they DPC that wall?

If they didn't DPC that wall then the moisture within often ends up diverting to internal walls.

If there is a DPC then I'm guessing it like a chimney situation - there's no damp proof membrane to the floor and the moisture from there is trapped on a small, poorly ventilated space. In which case venting it well should help.

You know old houses weren't made for chemical damp courses.

skinback69

you need to use renovation plaster after walls have been damp my mate had to have his house re done twice after the floods in hull cause they didnt use the correct stuff