Floor Insulation

11 Feb 2007
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United Kingdom
Have a mid 80's detached with suspended floors with air bricks.

Currently no carpets and gaps etc. at skirting boards, so plenty of draft opportunities.

The ground floor is split over two levels with three rooms open plan so a big area to heat.

I want to put in some insulation between the joists, and I'm leaning towards the cut to width boards, Celotex, laid on battens on the joists.....

Is this the 'best' solution in terms of thermal floor insulation?
The lower the u-value the better the insulation?
I need to 'foam seal' all around the edges too?

Any recommendations? thanks
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Not here for any confrontation or string of abuse.....but perhaps I'm incorrect but a response ending .....'(n)' = sarcasm?....helpful....thanks for your input
No sarcasm intended, there's a thousand threads on here asking how best to do this but you've got every aspect covered. Ensure your insulation boards are tight to the underside of your floor boards and you don't forget the gaps between the last joist and the wall.
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Saw the thumbs down and I've seen a lot of sarcastic responses on other threads, so apologies but I wasn't sure.....

So no air gap between floorboard and insulation, thanks

I'll do a search on other threads
Mmmm, something I forgot to mention is I'll be destroying the currently floor boards (old chipboard sheets), so as I'm laying a new floor is there a material I could use that provides any additional insulating properties?

If you have 200mm deep joists personally I'd prefer mineral wool. Cheaper, much easier to fit and avoids any potential condensation problems. It's personal preference though. Maybe price each option and go from there.
If you use squirty foam downwards to seal the cracks it will drip out for the first half hour, so use some stuffing to support it.

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