Damp in under stairs cupboard caused by poor subfloor ventilation?

[iquitelikethefudge]

We've a small Victorian terrace, the kind where the stairs run up the middle of the house with the under stairs cupboard accessed at the end of the front room.

The cupboard has a musty, damp smell and things stored in there are going mildewy. I lifted a board but the earth below was bone dry. The floor of the kitchen which sits on the other side of the cupboard is now concrete so there is no air flow coming from that side.

The musty smell is also in the front room, I can smell it strongly around the skirting but I've not been able to have a look underneath the boards as there is another floor on top of the original boards (the kind that clicks together, it seems to be impossible to lift up anywhere). Furniture in the front room also gets a bit of mildew on it.

We do have a couple of air bricks on the front of the house, outside the front room and there is also one on the side, still the front room. However, these are old and now sit below the ground level which has been built up over the years by previous owner's fondness for concrete.

The house is positioned on a hill and therefore water runs towards the front of the house when it rains.

I think I need to get new and more air bricks installed at the front and get rid of the concrete that goes right up to the house so the bricks are above ground level and water can't get in.

However, my question is, will it make much difference if there is not a proper through flow of air under the house due to the concrete floor in the kitchen? Or will having them on the front and side be okay, especially if they will now be above ground level?

This feels like a PigletJohn kind of query if he's around but any advice from anyone who has had this issue gratefully received!

[paxtecum]

Is the outside concrete above the damp course?

[PigletJohn]

"and now sit below the ground level which has been built up over the years by previous owner's fondness for concrete."

it needs to be dug out then.

this is such a well-known cause of damp that it is depressing people still do it.

[PigletJohn]

"The floor of the kitchen which sits on the other side of the cupboard is now concrete"

Quite likely there is a water leak. Have you got a water meter?

The leak could be in your neighbour's house, especially if the kitchens are adjacent.

[iquitelikethefudge]

I have to admit I can't tell where the damp course is because the house is rendered and then coated in a plasticised wall coating so it's tricky to see what's going on.

I intend to dig out the concrete/have it dug out, there's a lot of it

No water meter but I have wondered about a leak from next door. Wouldn't my sub floor be wet though? It's absolutely bone dry under the cupboard although the boards feel a bit damp.

[iquitelikethefudge]

I don't think my neighbours kitchen is adjacent though, she has an extension so my kitchen is her dining room.

[PigletJohn]

I was thinking of a pipe buried in a concrete floor. If you tape a piece of clear plastic tightly to the floor, see if condensation forms behind the plastic. You can also do this on walls. A common place for a leak in where the pipe turns upwards to rise through the floor.

A wall can also be wet if there is a leaky drain by it.

A water meter is a good way of confirming a leak, because it never stops moving.

[mygiddyantelope]

I have a related issue though the damp is in the corner of the cellar under the front room - there's mud even! I'm wondering how much would it cost to add an airbrick (there is only one in the other section of cellar), and also to dry out the mud and possibly deal with a leak in the outside wall or the ground adjoining the wall (I'm sure water gets in somewhere)? and how to know if the builder knows what he's doing before giving him the job?

I hope, OP, you don't mind me asking on your thread, if you do I would of course start my own!

[PigletJohn]

Quite likely a leaking drain.

How does it smell?

Are there red worms?

Is there a yard gulley or a gutter downpipe nearby?

Have you got a water meter?

[iquitelikethefudge]

Thanks PigletJohn, I really hope it isn't that, how on earth would the pipe be accessed? digging up the floor presumably?

Would you mind clarifying which wall and floor I need the tape the plastic to? Thanks!

[iquitelikethefudge]

No probs mygiddy

[PigletJohn]

tape plastic wherever there seems to be damp.

Moisture will evaporate from surfaces, and if it evaporates faster than it arrives, the surfaces will seem dry. The plastic prevents it evaporating, so helps you see if the floor or wall is damp.

If water forms on the room side of the plastic, it is condensation.

[PigletJohn]

In an older house, drains are pretty sure to be outside.

The water main usually runs under the floor, but if you have a cellar, is likely to be exposed, probably with dusty, rotted, moth-eaten felt lagging hanging off it.

[mygiddyantelope]

Piglet, yes there is a drain pipe outside at that corner but all around it outside looks very dry (and around the grate covering the whole in pavement) - it doesn't seem that pipe runs under the ground so I'm puzzled how it gets into cellar. The wall inside cellar does have a wet patch on it but not visible on same wall outside, and the floor there is really full of mud.

It's damp in cellar corner even in dry weather, though it's worse after rain as there is also a patch of wet on the pavement in front of the cellar (but it could be pouring from the window roof). When raining, again the actual corner around pipe doesn't have an obvious wet patch around it. The drain pipe looks strong so if it's leaking, do you mean through the wall it's attached to?

And it's gone worse when we tried to cover the wet patch in the front with a bit of plastic, thinking that rain water gets in that way - so it's definitely not enough ventilation, we took it off now but would you say we must put an air brick in, or is it just the matter of sorting the leaking pipe? Is that expensive and would any builder be able to do?

Thanks,OP. Good luck with your issue!

[mygiddyantelope]

forgot to say, I didn't see worms but I didn't look closely (yuk), the smell is just earthy and damp. NOt musty. Dont' have a meter.

[PigletJohn]

"It's damp in cellar corner even in dry weather, though it's worse after rain as there is also a patch of wet on the pavement in front of the cellar (but it could be pouring from the window roof). When raining, again the actual corner around pipe doesn't have an obvious wet patch around it. "

I would be looking for a clay yard gulley first. It is common in older houses for bath or sink wastes to flow into one, and for the rainwater to go into the same one. Clay drainage usually breaks. Gulleys have a U trap that breaks. As this is below ground level the surface might not be wet. If there is concrete it may sound hollow, or have been patched, because the leak will wash away the soil leaving a cavity. In some cases (and always with soil pipes) the iron or plastic pipe vertically goes into the ground and joins to underground clay. You may see a concrete or clay collar or socket that the pipe goes into.

If you dig into the mud you might find red worms, they are typical of broken drains.

Ask around for an recommendations of an experienced small local builder. Someone who has worked on lots of houses of similar age and style to yours. Your neighbours houses probably have the same problems as you, and some of them may have had it fixed. Usually you will find a whole terrace or street of houses, all with the same thing. If it is a broken drain it will need to be dug out and replaced with new. If you have a shared drain which serves several houses instead of each house running direct to the sewer in the street, you can get the water company to mend the shared part at their expense. This is very common in terraces where a common sewer runs behind the houses and turns out to the street at the end of the terrace. Or possibly down a back alley though we don't have them much round here.

Any small builder will be familiar with digging and laying drains. There are also specialists who can poke a camera down and identify the problem. Look for any inspection traps or manhole covers that may give clues.

[iquitelikethefudge]

Thanks PigletJohn. I realised I forgot a possible key piece of information- the damp/ musty smell is worse when it rains and it sometimes smells like fermented fruit?!

[PigletJohn]

I don't recognise the fruit smell, though breweries sometimes smell of strawberries so it might be yeast growing on organic matter. There will be more organic matter if it is a foul drain (sinks, baths and WCs) than if it is just rainwater, which might smell of wet leaves. Older houses are likely to have combined drains though. Red worms like organic matter.

I think you mentioned a bay window, so there should be some kind of drain connection for the rainwater.

If you find evidence of a leak, the water co can test the water and see if it contains soap traces (=foul) or leaf traces (=gutter) or chlorine (=watermain) or none of these (=groundwater). Or a plumber or drain person might sniff it for the same effect.

[mygiddyantelope]

this is so complex! all these types of traces..and gulleys and worms (I'd rather not see them!)
Thanks, Piglet. Just to add it's not a terrace, the whole street is semis or detached turn of 20th cen. Which is the simplest issue to fix out of those yo umentioned? I've asked my next door about buiklders and plumbers previously but she says she never used them, and btw her cellar is dry and is used as utility (but does have a drying machine) while she mentioned that previous owner of mine has 'moaned about the dampness in cellar' so probably it's not the mutual drain problem. The surveyor said he'd add an air brick but he hasn't mentioned problems, and indeed it's got much worse now than a year ago. So do you think it's also worth fitting another air brick or is it not relevant, possibly after the issue is sorted?

[PigletJohn]

the more air bricks, the better.

But I still think you should start by looking for nearby drains, because I think one is leaking.

Also, if you can find a young person with sharp ears, ask them to stand in the cellar on a quiet night while the stopcock in the street or front garden is turned off. Leaking waterpipes emit a faint white noise. You only notice it when it stops. A plumber also has techniques for detecting leaking pipes. If your pipe is lead or iron it is overdue for replacement with a new, bigger, plastic one.

You can sell the red worms to anglers as bait.

[mygiddyantelope]

thanks, Piglet. I do hope that repairing a drain isn't a huge expense!(?)

the worms! I'd have thought anglers can easily find them after it rains in the river banks, no chance I'd go near them though! cellar is quite dark too.

[PigletJohn]

£3.25 for an ounce

[iquitelikethefudge]

That'll offset some of the huge expense mygiddy

[mygiddyantelope]

hilarious, iquite!

Piglet, I'm miles away from the coast so demand might be low - or are they used for river fish? Maybe the OP is in the right area! More to the point I don't want to touch them with a bargepole, but anglers are welcome to come and dig for a discount!