Damp - we have tried everything over the last three years! Help...

[mumneedshelpwithdamp]

We live in a Victorian terrace with a living room that smells of sickly/sweet damp, particularly after it has been raining. There is some slight peeling of paint in one corner and black marks around the nails in the original wooden floor boards which suggests leeching of water. The main issue is the smell and that it makes us cough in summer (I think it's because of the mould spores). It is mainly wet towards the back of the house towards kitchen. I am concerned that if we don't fix it we will get wet/dry rot.

The house is built at ground level - no step (bl*y cowboy victorian builders) - we have lowered the ground levels by digging a french drain (filled with pea gravel) and have lowered the air bricks to below floor level.

We have had the radiators fixed as they were leaking. We have repaired a water mains leak. We have added vents to our windows. We don't dry washing indoors unless we have no choice and in that case we run a dehumidifier. We have had the drains checked - there is a small hairline fracture on the soil vent pipe but nothing major. We have fixed the various roof/gutter issues that we have discovered.

It is still it is very wet under the floor, I stuck a humidity monitor under the floor and it was 83% yesterday, the ground feels damp to the touch. There is a lot of rubble under there but not enough to be blocking the air bricks and I don't think it could be causing the ground to be wet to the touch. We have spent thousands and I am reluctant to throw anymore money at it (it would cost 1k to fix the drain hairline crack) unless I am pretty certain it will fix it.

Can anyone help?!

[homebythesea]

It really will be the rubble restricting airflow especially if you have double glazing. We had almost exactly the same as you- did the French drain and air bricks. But in conjunction with taking up the floor, removing the rubble, laying waterproof concrete and replacing wet joists etc. it was a painful process but the only way to treat the cause as opposed to the symptoms

[mumneedshelpwithdamp]

thank you homebythesea! It is a relief to hear you have solved it - there is hope for us.

I am intrigued by the waterproof concrete - i worry about using that as wouldn't it force the water up the walls?

[homebythesea]

You just got waaaaay too technical for me 😀

One tip- if your air bricks are now below soil level in your garden get a barrier made to stop them getting clogged up- we have "u" shaped concrete things around ours. We also had a vent put in the floor (discretely behind a sofa) to aid airflow.

[mumneedshelpwithdamp]

Just my paranoia that water always manages to find its way into our house some way!

Thanks for the tips re airbricks.

[WhoTheFuckIsSimon]

Positive airflow system? Not cheap but would help.

[mumneedshelpwithdamp]

Would we put the positive airflow system into the subfloor only or into the entire house?

[WhoTheFuckIsSimon]

A friend of mine has one and it's installed in the attic. I think because the air is slightly blown all round the house it totally circulates all the air.

[clarazabel]

I've got a Drimaster in the loft - sorts out condensation and damp but not sure it would help if the water is coming from under the house. Does keep the black spores away though

[butterflymum]

We installed a positive input ventilation system in the loft a few months ago (old house with single glazing) and have noticed a marked improvement in humidity levels. Although bought via ebay, it came straight from the manufacturer.

Drimaster 2000 and others

There are other suppliers of similar products if you google.

[butterflymum]

Forgot to say, another bonus is generally fresher air throughout (and cooking smells disperse quicker too). We opted for the 2000 model without an inbuilt heater, and whilst the top landing is noticeably cooler, it is not a major issue. Noise levels are minimal

[brodchengretchen]

When did you last have a building survey carried out on your house? An expert could tell you exactly where the problem is, because right now it is guesswork. You could find that it is money well spent, like we did.

(Btw - we have no connection with the trade!)

[PigletJohn]

Have you got a water meter?

[mumneedshelpwithdamp]

Interesting ideas re the drimaster - i think generally our humidity levels are okay - mainly due to the new vents. The main issue is definitely the subfloor.

brodchengretchen - we had a survey when we bought, not helpful and have had two independent damp ones. They were interesting at the time and prompted a lot of the work I detailed above but I don't really want to fork out for another one unless they come very high recommended for this specific situation!

PigletJohn - yes we do and it isn't moving when we switch all the taps off but I don't think it was moving before and we definitely did have a mains water leak. Is that possible?!

[mumneedshelpwithdamp]

I have come in today after a dry day and it smells a lot better - definite strong correlation between rain and smell.

[PigletJohn]

The meter should record if you have any taps on or if there is a leak. You may not see the numbers moving. Look for a round window with a bubble in it. The bubble moves when water is flowing through it.

It is very common for old water pipes to leak. Lead might last a hundred years, rarely more than a thousand , steel might last 50. Or more. Or less. If you are in a terrace it could be the pipe next door. Steel pipes often perforate at the elbow where the horizontal pipe turns upward to come through the kitchen floor. To detect a leak in the supply pipe, get a young person with good ears to stand in the kitchen while you turn the T for the stopcock at the side of the water meter on and off. You don't notice the hiss until it stops and starts.

An old house will usually have salt-glazed clay drains. There is probably a yard gully outside where the kitchen sink used to be when the house was built. It is probably broken. There is also probably a break in the bend at the bottom of the soil pipe where it turns horizontal towards the nearest "man-hole". These breaks wash away the soil so the concrete paving above has usually been patched to hide it. If you dig you may find red worms in the wet soil.

[PigletJohn]

if connected to the rainwater drains, the same applies where it goes from iron to clay in the ground beside the house, the clay pipe is usually broken at the bend.

[mumneedshelpwithdamp]

PigletJohn - immensely helpful! Many thanks. Your old posts have helped us fix the problems so far - hopefully the drain will be the last issue we need to fix. (I know old houses are always damp, but I have been in other houses on my road and they have never been as bad as ours.)

[Catsgowoof]

What are your neighbours' houses like?

Where does water flow when it rains? I used to have a house that when it rained the water ran down the pavement for quite a while then straight onto my front wall which got damp