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1890 House, damp soil under suspended floor - insulate or not?

Postby fasterstilluk » Thu Jan 14, 2021 3:12 pm

Hi all,

I've a Victorian semi on a slight hill, the rear kitchen stone slabs are laid on the ground, but the front lounge has almost 3 feet of suspended underfloor space. The middle ground bedroom used to have condensation issues and the previous owner fitted cellotex on the inner exterior walls.

The bedroom still smells musty, but I reckon the carpets have never been changed. I lifted the carpets and a floorboard and went under! the ground underneath is damp and any old discarded wood is too, I can see accumulated salts on the ground. The suspended beams look ok, no sign of damp, and there's a slate dpc, plenty of ventilation through. On a very rainy day the humidity under was 71%, whilst the room above was 51%.

So what should I do? I don't want to spend a fortune, and don't want to cause any future damp issues. I think it does need insulating as the carpets feel cooler even when the room is warm. Also from what I can see, I should just leave the soil, it's not wet, just damp (even on heavy rain days it stays the same).
Should I just chuck some mineral wool under neath, with webbing to hold. Or should I really sort the damp floor (how) and properly insulate?

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Simply Build It

Postby stoneyboy » Fri Jan 15, 2021 9:58 pm

Hi fasterstilluk
Don’t worry about the damp sub floor, insulate between the floor joists and hold in place as you describe.
Regards S
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