To worry things left on the floor become damp

[Summerofloaf]

I’m living in an old late Victorian terraced house. Wooden floors that do have some gaps in them. I can feel cold air currents coming through the gaps and the air smells a bit musty.

On the ground floor if I leave anything on the floor like papers or clothes after a few days or weeks they become damp and musty smelling. The floorboards don’t feel damp. There has been a DPC done some time ago. There doesn’t appear to be signs of rising damp. I’ve got a dehumidifier running in the living area and it is constantly filling up and needing emptying.

Could there be water in the space under the floor? Why does anything left on the floor become damp? Any ideas please and what should I do? Thanks.

Have you got underfloor insulation?

The fact that your dehumidifier keeps on needing emptying implies the room has quite high humidity. If so, then as water condenses and falls it will predominately fall to the floor, hence why anything left on it will get damp. Try an experiment, leave identical cloths in the room, one on the floor the other higher up (mantelpiece?) and compare them.

@Lemonlemon88

Have you got underfloor insulation?

No. When I shine a torch through the (few mm) gaps I can just about make out lots of rubbish, rocks and rubble under the floor.

Would you normally insulate under a floor like that?

@Ifailed

The fact that your dehumidifier keeps on needing emptying implies the room has quite high humidity. If so, then as water condenses and falls it will predominately fall to the floor, hence why anything left on it will get damp. Try an experiment, leave identical cloths in the room, one on the floor the other higher up (mantelpiece?) and compare them.

I wonder if the humidity is coming up through the floor or gaps in the floor though?

Items left at the height of the mantelpiece do not become damp, only things on the floor. Which includes rugs etc.

You could get a damp expert out to quote. Could be a leaky pipe in ground nearby or something?

I also live in a draughty Victorian terrace. We have slightly mouldy corners, try not to put anything in them so the air circulates and open windows often to ventilate. We also get lots of slugs in, delightful!

You can insulate under floorboards in a Victorian terrace, you'd need to ensure there are no underlying damp issues first (sounds like this might be one if it's got worse suddenly). They basically take up all the floorboards, fit insulation board between the joists then replace floorboards. Quite a faff to take all the furniture up etc.

Thanks, yes I have worried it could be a leaky pipe. It’s been like this a long time though, it’s only now I’m getting off my arse to do something about it.

There is a small soil bed at the front and any water seems to run a back towards the house instead of away, so there might be something need sorting there.

I probably will have to consult some sort of damp expert. Under floor insulation sounds good, it’s freezing downstairs in the winter so it would help with that. And yes I get the slugs!

If they can get under the house, they can install it easily. Floor and ceiling insulation will make a huge different to warmth in the house.

Advice: get an independent surveyor to look at it, not someone who works for a firm which treats damp.

We had gaps in the floorboards and it was freezing in winter. No damp though. My husband got under the floor (luckily he’s skinny because he went through a tiny gap in the cupboard under the stairs and there’s only about a 2ft gap,under the house at the front). He stapled insulation stuff to the underside of the floorboards. At the back where the gap is much bigger he put celotex between the joists.

I think You need someone out though as the dehumidifier shouldn’t be filling up that quickly x

We have floors/floorboards like this but no damp - have you checked that your airbricks aren't covered up with soil? That can cause damp issues by blocking the air flow under the floor.

We had this in our old 1930s house. Turns out they’d blocked the air bricks when building the terrible conservatory. Living room carpet would get damp and kitchen smelled really damp where the moisture got trapped beneath the laminate. Once we’d opened up the air flow it sorted itself over the summer.

Cold air is coming up through the gaps in the floorboards. Cold air can hold less moisture than warm air, so when cold meets warm, the warm will shed some of its moisture as it cools down.

As a quick an easy stop gap, you could stuff all the gaps between the floorboards with rolled up strips of newspaper, kitchen roll or old magazines. Get rid of the cold air and there should be less condensation.

Then you have breathing space while you first check the air bricks, and if that doesn’t reveal anything, find an independent surveyor to look at it, not a damp proofing company who have a financial interest in finding all sorts of damp.

What humidity does your dehumidifier say you have? Our cellar is about 69%

If there's rocks and rubble under the floor it could be forming a bridge over your damp-proof course, allowing moisture to travel up and into the wall above the DPC.

I used a draft blocker tape thing on mine. If you search ‘stop gap floorboards’ then you’ll see a few choices. It was really easy to do (although a bit time consuming going up and down every floorboard). It made a big difference.

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