Suspended floor insulating from ABOVE

14 Sep 2014
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United Kingdom
Contrary to everyone trying to work out how to insultae under the boards...

I'm trying to understand the potential downsides of laying something like EcoTec Floor-Foam Insulation above the boards instead.

I noted PUR/foam/wool products you'd use to insulate under the boards tend to have lower R values, but we'd avoid the hassle of lifting the boards or getting into the crawl space.

Does anyone have any experience of using this approach and product they can share?
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How thick is the product you have in mind?
How much will you need to saw off the bottom of the doors?

Presumably you are aware that insulation is dependent on thickness. Thin products have little effect.

I have 200mm knauf mineral fibre under my floors. It is treated with Ecose to prevent it shedding irritant dust and fibres. I will never use untreated quilt again.
Hmm, yes there is the question of how useful the above-floor foam is. It's quite thin (4 to 6mm) and has an R value of about 1.1 (vs 0.3 or so from typical insultation).
your idea is more of a mass draught excluder. no better or different to installing laminate flooring.
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agree. Draughtproofing a gappy old boarded floor is worthwhile, especially round the edges under the skirting where dirt blows in, but a carpet or other covering will do much the same.

For true insulation, the mineral wool is good, and because you can stuff it tightly into gaps and round the edges, better at draughtproofing than foam slabs and does not need precision cutting. Mineral wool is also non-flammable which I now consider important.

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