Can I ask a question about damp?

[CondoleezzaRiceKrispies]

Sorry, I know there are lots of these.

Have had two specific damp surveys done, who suggested we put in a DPC and do tanking between us and neighbour to one side (terraced house on a hill).

Our 'symptoms' are blistering paint and warped laminate floor beading on the same side as tanking recommended. No mould or damp smell. An electrician said the socket on the front wall of the house is damp.

Putting in a DPC is of course hugely intrusive, is this the only thing we can do?

have you found out where the water is coming from yet?

If you invite a salesman from a damp-proofing company into your home, you can expect him to tell you that you need to buy damp-proofing.

How old is the house

is it a cavity wall

has it got a dpc? how high above ground/path level?

does the gutter, downpipe or plumbing leak?

what is the floor made of inside the damp room?

is it damp under the carpet, for example next to a radiator pipe?

Thanks for replying, had thought my post was so deathly boring that nobody could bring themselves to respond!

Yes, am posting here because I'd like an opinion other than that of a DPC salesman!

House is 1935. Pebble dash type render, same as others in row.

Base of downpipe of next door neighbour's house was pointing the wrong way (ie on to our brickwork) when we first moved in, but we remedied that straight away and that was 2 years ago.

No radiator in damp area, floor is cement there (I think), with laminate on top.

How do I know if it's cavity wall?

No DPC in evidence, no hole marks in front wall, is that how you tell? There are two air bricks in the front wall that we had installed about a year ago as the original had been rendered over.

Damp area is the front half of the house, where we meet our higher up the hill neighbour. And apparently in the front wall plug socket.

Can damp travel from a garden wall into the house? The render is missing and cracked on the garden wall, and the drainpipe from next door was also pointing at that.

cavity wall: measure the thickness of the wall, at a window or doorway. About nine inches is solid, about thirteen inches is cavity.

Rows of holes are not a proper DPC. A thin black line in the mortar at about two courses up from the ground level when the house is a DPC. Rows of filled-in holes are where someone has squirted silicone into the wall to get a certificate they can send to a mortgage company (it has little other value)

If there are air bricks they are probably immediately below the DPC and will have been put in to ventilate the aispace under a wooden floor to keep it free on damp and rot.

Have a look and a sniff of the subfloor void. It is often easiest to lift a board in the cupboard under the stairs.

If you are on a hill the void is usually deeper and more spacious on the downhill side of the house and you can probably climb down and crawl about.

Go outside on a rainy day and look for water running onto the wall. If is often from a downpipe or dripping from an leaking or blocked gutter. A wet wall can easily take a year to dry. The downpipe might be blocked and leaking at a joint or a rust hole.

A garden wall that is touching or bonded into a house wall can conduct damp, but there is usually a cracl or gap between them, even if they were built touching.

Water can run down the gap between loose render and the brickwork.

Thanks Piglet, appreciate your detailed answer.

It's a cavity wall. No evidence of dark line, would I still see this given the pebbledash finish?

There's no understairs cupboard I'm afraid, and the same laminate covers the whole downstairs, so we'd have to lift that to get under the floor. The hill is fairly steep, next door's front door is about 18 inches above ours, if that's relevant.

The building work done on the house before we got it is all really shoddy, and a friend mentioned to us that perhaps the wrong type of plaster had been used and it was drawing water in. They didn't know anything about it other than that, they're not a builder and had just heard it somewhere, could it be a possibility?

Can't see any water patches on wall. The neighbours with the troublesome downpipe of 2 years ago had had a total refurb prior to that including new guttering, it had just been knocked out of place and was pointing onto where our shared garden wall meets the house.

Garden wall definitely looks like it's touching, but it's rendered so maybe it isn't actually touching underneath.

Another thing has struck me, the bottom half of our house has render on top of the pebbledash, could that be a problem? We are the only one in the row where this has been done, the rest have the typical 1930s geometric finish just round the door and window.

where does the damp appear to be?

Behind front door and under the stairs are the noticeable ones, where the paint is blistering, some plaster looks floury and the laminate floor beading looks manky and warped. This is the wall that joins our higher up neighbours. The blistery paint goes about 18 inches to 2 feet up the wall. Behind the front door doesn't feel damp, but looks it. I haven't decorated there yet, and it has the previous owner's satin finish paint, no wallpaper.

Recently I stripped the wallpaper off under the stairs and painted with matt emulsion, which has blistered and the wall feels cold and a bit clammy.

The front door needs a new storm seal, but I can't think that would be enough to cause moisture 8 feet away under the stairs. Am I wrong?

When I took the wallpaper off recently there was a patch of black mould similar to what you'd see as condensation in a bathroom, this was about 4 inches square and was beneath the bay window on the front of the house, which is the same wall where the electrician said the socket was damp.

'mmmm

I'd like you to make sure you know what the floors are made of. A house of that age could well have a leaking water main or other plumbing.

If the floors are wood, you can easily have a look underneath and a sniff for damp (yes, laminate flooring is hated by plumbers and electricians), you might even be able to hear a faint continuous hiss. If you have a water meter it will be easily detectable. Leaks are often under the kitchen or by the stopcock, where there are joints and elbows.

If the floors are concrete then it can be very wet and water can soak up into the building.

However a 1930's house really ought to have a DPC to stop water going up into the walls (it is fairly difficult to cause rising damp)

It is also possible that there might be a leak in your neighbour's house, and if they are higher than yours, it might be getting from the floor into the wall.

As you are on a hill it is also possible that water is running downhill, possibly from broken drains, and getting under the house.

If you can get recommendations for an experienced old plumber and a local builder who is familiar with houses like yours, they might be able to puzzle out the cause. Sometimes when you strip the paper off you can detect where the wettest patches are, and the source is often near there.

Damp-proofing will certainly not cure the cause.

BTW condensation, damp and mould in UK homes is usually caused by lack of ventilation and draping wet washing around the house or over radiators. You don't do that, do you?

p.s.

water mains srvice pipes very often run from where the stop cock has been lost, in the front garden next to where the gate used to be, to the place where the kitchen sink used to be. Sometimes one of the houses in your street will not have been altered and the stop cock will still be visible where it was originally put. Houses built locally, especially in a terrace, will often have been put up by local builders and plumbers working in the same way.

Blimey, all sounds a bit scary!

There is definitely one area of concrete flooring, near the back of the house. The wall there is dry (although maybe that's because there's a radiator there?). I'm not sure whether immediately behind the front door is concrete or floorboards, will have to do some jumping up and down.

When we had our oil heating converted to gas the installer did get under the floor, he didn't comment on any water there, and the problem pre dates that. Looks like we should get someone else out to look. In terms of running water, the neighbour on the other side who is lower than us has no problems. We don't have a water meter.

How do I know if there's a DPC if there is pebbledash?

We very rarely do the laundry thing, as I know it's bad re condensation. We have an open flue and have windows permanently open so hopefully that counteracts the 'sealing up' effect of double glazing and laminate floors.

Thanks so much for trying to help, I really appreciate it. Just had a feeling that the DPC wasn't the answer, and our next door neighbour on the lower side was really surprised when I'd told her the surveys had recommended one. She's lived there for 30 years, and the house was her granny's before then, so she knows the history of the houses in our terrace.

if it's a 1930's house, I'd expect it to have one. Pebbledash is not supposed to go right down to the ground. If any of the other houses have exposed brickwork, you should be able to see a thicker mortar joint, about two courses up from oroginal ground level, with either the edge of two layers of slate in it, or a bituminous black layer.

If you look at some other houses, once you have seen a few, you will easily recognise it.

I am beginning to think the source is in your upstairs neighbour's house, and may be a leak. It is not so common for internal or party walls to be damp.

If someone can lift the boards they will be able to see if the ground or concrete under the house is wet, and if the party wall is wet.

If yoy CH installer got under the floors, they will be wood. Wooden floors need to be well-ventilated underneath through the airbricks to prevent rot. Yours may be unhealthily damp.

If you hit a few floors you should learn the different sounds wood and concrete make.

uphill not upstairs

Yes, most of the floor is definitely wood, there is an area about 8 by 8 feet that is concrete, it's the area behind the front door that is in doubt, as my neighbour has original tiles there. Will bash about and find out.

Oh god, damp joists sound really worrying, but I guess we won't know til we get the floor up. Holy Moses.

it might have been for an original porch or tiled floor where people would come in wearing wet boots.

See if you can find the old stopcock (might be one in the pavement or in the front garden) and the site of the old kitchen sink and puzzle out if the water main might pass through the damp area. An old plumber can detect a leaking main using a glass of water...

Are you a builder? You have a fondness for old plumbers that makes me wonder if you are one.

This whole thing has left me feeling a bit discombobulated, wonder what would have happened if we'd just followed the advice of the damp surveys and put in a DPC, presumably a lot of money wasted and still damp. Wonder why the surveys didn't suggest the problem could be something different.

I know a good one-man general builder who I trust, will get him to take up the floor and see what he finds.

Does the party wall go right into the ground, or will we be able to see under their house? If we find the party wall is wet below our floor line but we can't see anything obviously coming from next door, what can we do?
I think the damp surveys flagged up tanking because of our floor level being below their's IYSWIM.

old plumbers and old builders, if local, will doubtless have seen hundreds of homes just like yours, and should know what to look for, and probable cause.

The party wall must go down to the foundations. If it is wet, and the wetness diminishes as you move further away from it, that would be strong evidence. If you drill a hole in it and water comes out, so will that. The water company can test water and can tell if it is groundwater (contains soil particles), gutter water (contains leaves), sewer water (contains sewage), bathwater (contains soap) or mains water (contains chlorine). An old plumber will probably know by looking and sniffing it. Once you know the cause, the cure is much easier.

the damp-proofing treatment would have hidden the damp. It might later have emerged somewhere else, since the source of the water is not addressed. Suggesting tanking means he thinks the damp is coming through the wall. It is quite difficult to cause damp to rise up good modern brickwork by more than a few inches.

That's great, I'm learning so much! Don't know a local plumber sought have to start with my builder contact.

I'm guessing we'd need to pay someone for this type of investigative work, as it involves lifting a floor as getting down a hole?

I think so

if you don't, they'll be planning to overcharge you for remedial work (like every an untrustworthy damp-proofing company

Seems fair to me.

Thanks again Piglet, you are a marvel. Will try to track down aged plumber, or failing that, builder mate.

Will let you know what happens!