Friend's house has rising damp and some woodworm. The part that is concrete floor has RD, including internal walls; the wooden-floored area is similar plus a bit of WW. The DPC is slate but is almost flush with the surrounding paths; there's no doorstep (rise) into the house. House is brick, built c. 1950.
In this field there plenty of 'cowboys', often armed with a pointy object in one hand and wood powder in the other. I'm after some advice on how to filter out the bad ones, please.
Have a selection of people come to quote. Carefully compare what they say they will do, and what it will cost to do it.
That said, if you or a friend know about damp & woodworm, or can get a builder to look, do it.
First thoughts are "Anyone can spray for woodworm, it's not a difficult or technical task", and "Perhaps do something about bridged DPCs or where the level of paths is near the DPC". Very often the DPC is OK, it's just bypassed. The same could possibly be happening inside if the concrete bridges the DPC, BUT then there should be other signs supporting that.
Photos?
PeterC formulated on Saturday :
They are all bad ones, rising damp is mostly a myth except where there are faults in the building such as plaster bridging the DPC, or path/ soil levels which have crept up over the years since it was built. Sort those issues out and no need for a damp specialist.
Generally the injections do not work, fix the root cause and it will dry out.
It's a minefield from what i've experienced.
As the other respondant suggested i'd be getting a builder in rather than a DP 'expert'.
The woodworm should be easily sortable and won't be an ongoing problem if you can get the place dry.
The damp issues, I feel as if you'd be as well to work out why there is moisture appearing to travel up through the wall and deal with that.
I haven't read all of the above links but if you search the matter and do some reading (there's plenty) you'll probably come away with a different idea of what the problem is and how to actually deal with it.
I'm not suggesting that there's no place at all for a DPC but in the most part it looks like throwing good money after bad.
+1 (also to what Chris and Harry say. DAMHIK)
Has the house been modified for a wheelchair at any time? I've heard of the no step modifications causing damp course issues before, also might not be good if you get lot of rain!
Brian
The DPC being bridged is probably the main cause. The level of the concrete path might be original as it was installed when the house was built (all of that style of house have the same); the concrete yard could be a latere addition but is at the same lavel as the path.
True, but if the internal concrete raft is also almost on the DPC, that's a major job - raising the floor is one thing, raising internal, load-bearing walls...!
Get the outside fixed first.
Those two say 'no rising damp'. As for there not being capillary action in brick, my rustic facing bricks are dry in the summer but in a wet winter the outside third is a bit paste-like when drilling a hole well up the wall.
He claims that RD exists. Certainly does in plaster.
I'm not sure about RD where there's a suspended wooden floor. although the joists are below DPC.
My house has concrete floors, a good DPC and a step up but has a bit of dampness on an internal wall. Shouldn't be condensation - no cooking other than microwave, thermostatic kettle, good fan in the bathroom and showers, little use of hot water and only one person.
I'll as the builder who helped with the chimney to have a look. I'll also give my friend some advice on reducing emission of moisture (cooking, bath, letting the kettle boil to a stop, drying laundry, no extraxtor fan, almost no heating (/that/ time of life!) etc.).
To add to that, although it's hard to know without pictures, hire a disc cutter for concrete, 300mm is probably going to be big enough, and cut a line 6" minimum from the wall through the concrete. Break out and remove the 6" or so strip. Backfill with pea gravel to a brick below DPC, which will probably be OK and look OK.
Timber floor joists should be borne on sleeper walls independent of the house walls, with their own DPC.
Beadles of Cawston in Norfolk are very reliable if you are in their catchment area.
Mike
That's a possibility. I must check more walls and try to get a look at the joists.
Northampton-ish, unfortunately.
This Victorian house has no DPC. When I bought it, the BS required a damp and timber warranty. Most firms wanted to install a DPC and a waterproof render to the inside. Which would mean removing the rather nice original skirting, and impossible to replace.
I eventually found a firm who removed the ends of the joists going into the walls and supported them on pillars, etc.
There was no damp showing anywhere internally - although of course a meter showed moisture. But there was rot on a few joists where they were on wood wall plates into the external walls.
when I went to Manchester for work it seemed to be accepted fact that the majority of historic terraces houses never had a DPC in the first place and that checking remedial work was required for any house that you considered buying was absolutely necessary
AIH my first house purchase attempt fell though and a better job opportunity elsewhere within the company became available and my lack of ties to the location meant that I could take it
Dodged a bullet there
Many do have damp-proofing, it is just not obvious. For instance, my parents' house appears not to, but the type of bricks used provide their own damp-proofing effect.
When they put in a patio door some years ago, my uncle helped (he's worked in building all his adult life) and he commented that he'd never seen such a dry wall before.
Presumably all the houses built there in the 1930s have the same system.
The properties I'm referring to were not built in the 30s
40 years ago it seemed common in SE Essex to get a mortgage on any property that you had to get a damp proof survey and woodworm treatment. A sum of money was always retained until proof of those treatments had been carried out or were unnecessary. The surveys were carried out by woodworm and damp proof companies who had a vested interest in doing the work!
My guess that installing CH to most properties would have stopped any further woodworm damage and cured most "damp" problems, especially those e found by the "surveyors" who measured the resistance of any salt in the plaster with their two spiked probes :(
As others have indicated check that the DPC hasn't been bridged and/or any damp isn't being caused by a water getting in via a rotten window cill.
They ALWAYS indicate moisture irrespective of damp or not!
But there was rot on a few joists where they were on wood
But possible where the wood was in contact with the wall below the DPC. On my 1908 house there was a lot of debris at the end of the joist presumably from when they built the house and any mortar or plaster that had fallen was just left in situ.
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