Rising Damp: Partition Walls and Heating

I know there are a lot of posts on AAM but I haven't seen this situation arise before.

We had a survey done on the terraced, high-ground house we have made an offer on by an engineer surveyor. The surveyor was enthusiastic about the house, which he said was structurally sound, but pointed out a small amount of damp.

He was of the opinion that given the age of the house (old), were this a serious problem the damp would have advanced further up the wall than the two or three inches it has so far. He didn't seem particularly concerned about it, and frankly neither are we. The house currently has adequate ventilation through working fireplaces in the two affected rooms, but no central heating. The surveyor seemed to feel that installing central heating would go a long way to resolving the problem.

We are planning to take the footprint walls right back to the stone anyway, and could damp course them at that time. However, there is also damp on partition walls which we are planning to take down.

My questions are:

1) In a mild rising damp situation like this, is the addition of heating potentially enough to sort the problem or will a damp course definitely be needed?
1b) If it turns out to be needed, any idea of costs? We're looking at an open plan room 20 feet x 12 feet. (I'll call around on Tuesday but I'm curious to get a general idea sooner than that if I can.)
2) If there is damp on the partition walls, do we need to do anything special around their floor areas after we take them down, or will taking them down make the problem go away there?

Thanks!

PS: If AAM isn't the best Irish board to ask about this sort of thing, I'd appreciate it if someone could suggest a better place -- I don't mean to be a pain!

Central heating will dry out a little damp but efflorescence may result.
If dampness is migrating into the plasterboard/partition wall, then the said wall is in contact with dampness. Plasterboard should not go right to the floor and it should not be touching the block/stone/brick in an old house (where you might expect lateral penetration ........ such as retaining walls, defective render on outside etc). Dampness will also pass through timber joists onto drywall systems. Once you take down the wall, treat the channel in which the timber plate was and level off with waterproofed sand/cement. You may find that the two rooms are not symmetrically level at various places. If so, apply some self-levelling compound.

Thanks, that's very useful.

The entire concrete floor needs to be leveled anyway. What is the best way to treat the channel before sealing and leveling?

I would suggests that you talk to Protim Services Ltd or The Damp Store. Both these companies have the professional expertise to help you with this situation & will issue you with a report. Also I note that I have no affiliation with both these companies.

Hells_Belle said:

Thanks, that's very useful.

The entire concrete floor needs to be leveled anyway. What is the best way to treat the channel before sealing and leveling?

Click to expand...

If the channel is showing signs of dampness, rake it out, hoover the dust, paint the sides and bottom with blackjack (at least two coats) and fill in with a semi-dry sharp sand/cement mix (3:1).

Thanks guys.

We went and poked around again today and we don't think this is a big problem. The only wall with an apparent water line is the partition wall adjacent to the chimney, which appears to be un-capped and is the likely source of the water.

So I'll knock down the walls (not the supporting one!) and seal the channels and just get on with it.