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suspended timber floor over bare earth - insulation ideas - Green Building Forum


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suspended timber floor over bare earth - insulation ideas

Hello, just joined up here. I wonder what folk think about retro-fit insulation under a timber/joist floor, ground floor over bare earth/rubble? We have an old (1897) house built on brick foundations and piers directly in heavy clay - London, UK. Basically beneath the ground floor boards is a void of 0.5m and then clay rubble. It's well ventilated with air bricks and subsequently very drafty in winter - cold air can be felt coming up through skirting and if we remove carpets as planned it's going to be ridiculous! 

I found this link very useful: 

I need a cheap, ECO and DIY solution and have come up with this. Knauf EkoRoll 100mm batts beneath the floorboards and between joists, fixed by stapled straps or some kind of fabric roll (similar to garden weed supressant) or board out beneath joists with something like HARO fibreboard underlay. I can do this at a cost of approx £5 per m2. I'd appreciate any feedback on this idea, especially the use of boards and mineral wool .. is it overkill? The basement section beneath hall is almost full height and I do use as a workshop so do I need to think about fireproofing?

I believe its a good idea to continue to allow the house to breath and this seems like a good compromise to using insulated board (celotex) and foam which would be more expensive and also isn't as green.

Any thoughts?


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