Riing Damp

[Poppy]

After recent storms the bottom of our internal walls are damp and plasterboard is breaking up. I suspect there is no damproof course in the walls. Does anyone know if the chemical injection stuff is available in France or I would be very grateful for any other ideas.

[Alan Zoff]

May be something else in your case but we had damp walls and ruined plaster simply as a result of the soil level having been allowed to accumulate well above the damp proof course - instead of well below it - so water went straight through brickwork. Previous owner had tried to tackle it by putting waterproof concrete on inside wall in place of the ruined plaster but this merely pushed the damp further up the wall.

Only solution was to excavate hell of a lot of soil to get the outside level down below DPC. Walls eventually dried out and we were able to replaster without further problem.

The above related to our English house but we had a not dis-similar problem with French house. Soil had accumulated above the air vents on two sides (the house has wooden floors with - supposedly - an air ventilation void beneath). A fair amount (8 wheel-barrow loads!) of soil had gone through the vents and was breaching the gap between the soil and floorboards, allowing damp into affect the joists and boards.

So well worth anyone checking their ground levels. Prevention better than cure....

[Just Katie]

Poppy, when you say on the internal walls I assume you meant a wall partitioning two rooms.

However, Alan (I think) has assumed you mean a wall, which has the exterior on the other side.  If Alans assumption is correct, then so is his advice.  You would need to look at the soil level externally to start with.  I live in a very old stone house in UK and also suffer a little this problem on my "exterior" walls.  I live with it.  My house is still standing after 200 years and it comes and goes with the seasons. However, this is only about 6 inches in height and about 1ft wide.  If DPC exists in France this should remedy your problem.  If there is too much soil to excavate they could advise you on tanking the affected wall.

If the walls are 'internal' meaning partitioning two rooms, then I would assume you have a very old stone house.  Again, this would be quite normal in older houses with flagstone floors.  As long as it is not touching any of the wood supports it will not do much harm.  However, if it bugs you that much and DPC is not available you could consider having it dry lined.

[Alan Zoff]

I have found the following website to be helpful in relation to a lot of house maintenance problems:

www.diydoctor.org.uk

[Poppy]

Many thanks for the replies.

Sorry  I confused the issue by saying internal walls. Its the inside of the external walls, if that makes sense. It is an old stone house and we decided to line the kitchen area with plasterboard. Having spent a few days digging it might be a drainage problem and we have to divert water before it hits the building. It will probably only happen a couple of times a year and we wouldnt worry except we have have bought what to us are expensive kitchen units which will be butted up to damp wall. will definitely not line any other walls, just let them breathe/evaporate.

Thank you Alan for the diydoctor website will certainly have a look at that.

[Alan Zoff]

I'm not a builder.  Nor have I owned a stone house. I doubt however that an old stone house would have a damp proof course and would guess the weak point in such a house would be the mortar joints. Worth checking the pointing near ground level and making good if necessary, perhaps with the addition of a waterproofing additive to the mortar mix?

Alternatively, you might "tank" the bottom of the wall with bitumen (I have done this on an outbuilding made with concrete blocks) but this may be cosmetically unacceptable with a stone house.