Yes.
Possibly drainage round the house..if you have a suspended floor with the party wall sitting in a small pond under it, you can improve matters by draining the pond first..
Just about. A waterproof render around the injection area at least means the plaster won't form a damp bridge
Other internal walls (brick) are also damp.
Dunno yet, haven't been under there.
Yes.
I know - in fact, I'm the one usually giving that lecture!
That's what we've tried to do so far.
We really have done this - ventilated, heated better and fitted a dehumidifier.
No.
Yes, been there done that ;-( you can get water based injection fluid which is not as obnoxious to use as the spirit based silicone, and is ok when a much cheapness referb is required. But I have no personal knowledge of its long-term effectiveness.
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I'm always a bit wary of adding extra water to an already damp wall, especially under pressure! That said, if the house is quite dry and it's the middle of summer, I don't suppose it would matter much, but I've still not got my head around water based fence preservative yet.
Ok, thanks for the advice.
Would you recommend these products over a high pressure pump setup? My hire shop does a pump + 25 litres of fluid for £92 (/day).
Probably not, despite what people who install it might tell you :-).
If you can do it, the one thing that will cure it is the original system which would have been used to keep damp at bay, a French Ditch.
See
and
(the pages don't seem to be directly accessible at the moment)
If it has been double glazed or has well fitting windows and doors then ensuring there is adequate ventilation is also worthwhile. A whole house ventilation system can be fitted for less than the dampfmeisters not-so-magic glops and will make for a much more comfortable environment.
Ah, but it is internal walls that are damp - external walls are ok.
We really, honestly have done this - the house is reasonably well ventilated, and has a dehumidifier.
You don't have to convince me about the damp scams - I know all about them. But in this case, it is the bottom foot or so that's damp, and on internal walls.
I wouldn't dream of getting someone in to do this, hire shops do a pressure injector + fluid for under £100.
Didn't you check which kind of 'damp' it was first by mounting a glass slide on the wall with a ring of Plasticine? Damp condenses on the inside, condensation condenses on the outside IYSWIM ;-)
Phil
That's a neat trick Phil - I'll try that next time I'm there, but I'm pretty sure it is rising damp. These are internal walls, so not cold enough to get much condensation.
Yes, IMO.
Apart from what the others have said...
See
On the other hand, the very informative article
I used high pressure injection 10 years ago in an outhouse type extension that had no DPC (and precious little footings) and the damp has not risen through it since. The post referenced above refers to that project. Due to leakages through various cracked bricks, I'm pretty sure the mortar got a good soaking too, so maybe that's actually why it has worked.
The DryZone stuff looks worth a go, certainly much less drilling than the way I did it - do they offer a guarantee? Alternatively, if injecting again, I think I would try injecting a course of bricks with 2 holes per brick (as I did before), AND make sure the mortar bed above and below gets soaked as well. Belt and braces ;-)
The injection pump comes with a manifold feeding several injectors so you can do several holes at a time. It takes quite a while to percolate the stuff into the brickwork so the more the merrier. I think mine had 4 lances. And the pump makes a frightful racket.
The fluid is primarily white spirit (at least in the stuff I used) being a carrier for the active ingredient, and it took 2 or 3 days for the smell to subside afterwards.
HTH
Phil
Great news - I've been waiting for someone to try them out. Can you give any more details of the job/s you used them on?
Thanks Phil, most useful.
With the white spirit based liquids, you'd think rendering would be difficult afterwards - comments anyone?
The treated brick should be behind the skirting board, so no, rendering should be straightforward, but heed the advice about 2nd coating over waterproofed render in my other post. Also don't 'spray' up the wall with the DP fluid, and don't render down to the floor, leave a gap of a few inches.
That's the common dampfmeisters scam - "ah look - internal walls - must be rising damp". The house was designed to have damp feet. It wasn't designed to have wet feet. The idea of the French ditch is that it essentially isolates the house on an island of dry soil. With imperfect foundations and the original damp control system probably destroyed over time it is inevitable it will get wet. Leaving it wet and putting a bit of temporary (for that is all it is) water reduction glop in the wall is about as effective as trying to stop an oil leak with elastoplast.
There is also the problem that treating one side simply moves the problem to the other. Dampglop doesn't stop water rising, it merely slows the rate down a little bit. The waterproof "plaster" is an essential second component which allows the wall to stay wet without the results being too noticeable. On a party wall if you plaster one side the water simply goes to the other which is really going to please the neighbours no end.
As with any water problem you need to eliminate the problem at its source - not stick things on afterwards in the hope they will work. A French ditch achieves this by removing the water from the house. Once this has been done there is no need for elastoplast treatments.
I really would have a peep under the floor if possible. I had a neighbour in a victorian terrace who discovered a pond under his living room floor, as a result of a cracked cast iron pipe. I forget for the moment whether this was the bathroom waste, or from the roof (the gutter downpipe was cemented into the party wall and coupled somewhere into the normal drains).
Hmm, ok, I see where you're going with this.
The problem with the French trench approach is implementation. I'll explain.
A few years ago, we had a damp problem, which you advised me to remedy by putting in a French trench. We did this, along with fixing the heating + ventilation issues, and it worked a treat.
Putting in the trench was easy, because our house is detached, and essentially stands in the middle of a field, surrounded by soil.
This friend's house is a different kettle of fish. It's a semi (actually, it's an end of terrace), it fronts onto a public road (so the front wall of the house meets tarmac at its foot), and has a concrete yard along the non-attached side and part of the back. Achieving a continuous trench around the house would be impossible without a) digging up the road and b) continuing the trench around a long row of terraced houses :-)
Given this, what would you suggest?
I will try to, but TBH I'm not even sure it's a suspended floor - there's currently laminate there, so I don't know if it's over floorboards or concrete.
It depends on the construction of the party wall and the condition of the bricks and mortar. With pressure injection Ive had a neighbour go ballistic about the smell, and worse I leaked a gallon of the fluid into a neighbours kitchen, that didn't go down well either ;( Dryzone is more expensive but for use on a party wall its almost odour free and being a grease like substance shouldn't leak into next door. I can't stress enough that the re-plastering is perhaps even more important then whichever DPM you use, both in the admix dilution, mixing and coat thickness used.
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