Rectifying damp cellar

Fiona McKenzie, Hello. I have a damp cellar in an old stone house. Air vents don’t seem to have worked as much as I’d hoped. The window side faces the road and the window height is almost level with the road outside. I’ve visited the Marie and looked at the plan and no water drains run alongside the house. I have water pipes on that side of the house as the washing machine is plumbed in there. I will try attach photos. Would it be possible there’s a leaky pipe? And how does one check without ripping chunks of wall off?

What type of floor do you have in the cellar?

so, your cellar floor is below ground level…

could be water seeping in through the walls and/or water from down below the floor…

We have laid a thick bed of pebbles, as damp definitely passes across the earth floor of our (below ground level) old cellar…

We have an old stone house built into a slope so that roughly half of the cellar is below ground (roughly 10 feet below at one end). The cellar has an earth floor. When we first moved into the house, the damp was so bad that when we opened the cellar door it set off a smoke detector.

To fix the issue, we unblocked all of the vents that the previous English owner had blocked. We then added additional adjustable vents in 2 of the cellar doors. All this increased airflow across the cellar. It took roughly a year for the damp to almost completely disappear.

The cellar also has a well and a sump. The water level in the sump used to be only a couple of inches below floor level. We installed a cheap submersible pump in the sump, and now the water level is around 2 feet below floor level.

After periods of heavy rain, the earth floor was still a bit damp, so we covered the entire floor with limestone gravel to a depth of about 3”.

We considered installing a VMC like thisÅMÅŽÕÑ&crid=MZTQY9TQMJQL&dchild=1&keywords=vmc&qid=1635156894&sprefix=vmc%2Caps%2C99&sr=8-9

but now there’s no need.

I suggest viewing Peter Ward’s videos on YouTube. He is an expert and will help avoid many common mistakes that people make when attempting to deal with damp.


Hello. The floor is tomettes. They seem to be laid on a solid (?) bed, if that makes sense. The opposite side of the cellar is dry and has the same floor.

Hello Stella. Directly outside the window is the pavement/walkway as its a village house. Did you put gravel alongside the external wall?

Hello Nigel and thank you for your reply. Yes, Peter Ward is a hero. I’ve watched all his videos. Its interesting that you mention the floor as I hadnt considered that. I will watch the attachment you’ve given. I wonder whether I should put more vents in. They are currently in the window. Is it possible to get a new one through the thick wall?
Above this part of the cellar is the kitchen and front door and on entering the house theres that typical damp smell. I’m very aware

of avoiding remedies that merely mask the problem. Thanks again for your time.

We put a wall outside our house, which stopped the rain coming downhill directly at us… the water now bounces off and wanders elsewhere… yippee.

But the groundwater still seeps along, deep down below the road/pavement…

We do have an ancient tunnel which also has water way down… and, of course, the well is only yards away from our house… so there’s a lot of water and it’s bound to enter unless one tanks the whole cave… which is impossible in our case.

Many folk in this village have water/dampness in the cellars… but the water runs away… and good airways do help keep things ok. plus it’s great for keeping low temps for the wine…

Thank you Stella. I think I managed to attach a photo. The smell bothers me, that said it does improve once the house is occupied for a period.

Have you tested the walls with a moisture meter to determine which ones are damp?

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Oh my… yours is a proper room… ours is just a large empty space, carved out of the rock, underneath the ground floor boards… there’s a dodgy enclosed stairway going down into the blackness… and bats used to hang from the sides of the walls and frighten the life out of me (at first) when the torchlight disturbed them.
Now with regular lighting fitted, the bats seem to have moved up into the attics

Hi again, your attachment is the VMC. Yes, I got one put in. It doesn’t include the cellar just the two floors above. I’ve finally managed to attach a photo. The walls look in quite a bad way really.

Have you got a sink in the cellar… just wondering in case the “trap” is drying out and allowing smells from the drains et al … to permeate the place when you’re not there.

Certainly, with any unlagged pipework, there will be condensation … which doesn’t help… and some of those joints might be slightly weeping (or whatever…)

Possible damp coming from within as well as without…

a bit of a puzzle…

That happened to us - but it took a period of unseasonably hot weather. Returning this year after a very long absence the traps had generally not quite dried out (but were noticeably low).

happens every year to neighbours… they spend 3 summer months here and, before leaving, have to block the toilet with a special (homemade) contraption… and leave the plugs in the sinks/bath and cloths blocking the overflows etc… otherwise it stinks by the time they come back. doesn’t help that they, too, have water coursing through their cellar… coming through the rock. They’ve put in special drainage points…

Thank you. Yes, there’s a sink but no in use. I will check the trap for sure. Yes the pipework is unsightly. I didn’t think to get it lagged, good idea. Thank you.

unsightly doesn’t matter if it works and is lagged… but worth checking all the joints etc… just in case.

For an unused sink… I leave a mix of bleach/water just enough to fill the trap, then put in the plug and block the overflow with something…

quite often… a problem can have more than one source.

I wonder whether the solid floor under those tomettes is concrete? If so that may be the cause of damp in the walls. I’ve a couple of friends who laid concrete floors to replace earth ones. Unfortunately this has simply forced the damp / moisture into the walls. I strongly suggest that limecrete is used instead of concrete.


Sorry to have taken up so much of your time. Interesting point about the floor. I could get someone in to help determine if the tomettes are in concrete. When I’m next there I’ll see about getting a builder in and mention all the suggestions from today. Thank you.

Good tip Stella, I’ll do the same when Im there in December. Thank you. Fiona