Damp Proofing

Standing water in cellar and damp joists, what's the best solution?

Anonymous user 23/02/2024 - 3.21 PM

We have a cellar in our house under the living room that has water coming into it, apparently from a nearby stream. There is a sump and pump to remove excess water, but there is still standing water. We had an insulation guy come round yesterday as another problem is the house is pretty cold, but he highlighted the damp in some of the joists. One of them has 25% damp, the others are around 18-20% (I haven't checked every one). He deals with spray foam and said this would insulate the floor and allow it to breath, but I've heard conflicting things about this stuff. At the minute, there is celotex between the joists, and he said this is trapping moisture and leading to the damp. I was thinking of putting a dehumidifer down there to try to take away some of the moisture, but I wonder whether the ingress would mean whatever water I take from the air will just evaporate from the standing water and replace it. We have an open fuel chute for ventilation (though of course that makes it cold). The other thing to add is that there is an adjacent cellar under the dining room which you can only see through a small hole in the wall - it is mostly filled with rubble, with perhaps 3-4 ft of space under the floodboards. You can clearly see the floor hasn't been insulated there, I guess because it would be impossible for someone to access. This means the dining room floor is freezing. The insulation guy suggested filling this hole so seal off the cellar, to help prevent cold, but to me it sounds like a bad idea in terms of ventilation and damp. I haven't checked the damp levels in those joists yet (in any case I'd only be able to reach in enough to check the first one or two). Is there some kind of expert who come come round and tell us whether the dampness in the joists is a problem, and what we could do about it? And because we originally got someone round about insulation, whether this person could also advise against this? Something we realised with the spray foam guy is people will come round to promote their own product, so we can't actually work out what is best. Any advice would be well appreciated!

PT Renovations

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Faversham

Hi Daniel. First thing is to sort out the water ingress. You have a sump pump that is good. Now you will need proper drainage channels to collect all the water ingress from around the cellar. Good quality pump on up and down float would be perfect. Once above is in place then dependence on budget we can get further improvements. Most important is to stop joist from taking so much water into as this could lead to major repairs or even worst collapse of the leaving room ( do not panic it dose not happen so quickly). Once those 2 are done then we can insulate the whole cellar with proper cavity drain membranes ( type c waterproofing) and seal whole cellar so it becomes damp and water free, Then we could install battens celotex and plasterboard. This the proper conversion. Please remember to drain that water asap as this cause the joist getting wet Please feel free to contact me via my builder and we can help. Kind regards Peter PT Renovations

Answered31 January 2019

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