DIY Doctor

Celotex as loft floor insulation?

Postby Flinto » Fri Dec 25, 2020 4:44 pm

Hi. Help / advice please from an insulation expert.

I've acquired a significant amount of used 25mm foil backed celetox and 50mm paper backed insulation. It's in my garage and I need to either use it or get rid of it somehow.

I thought I could use it in my loft to top up the existing insulation a bit. At the minute I only have 100mm of glass fibre.

Initially I thought I'd lay it between the joists and put the existing glass fibre on top.

The I thought it would be a lot easier just to place it on top of the joists as it is.

Then I thought, could there be any condensation issues with the foil backed? Or any of it.

Then I thought, I really don't know if I can use it all, and maybe I'm best just adding 170mm of glass fibre or equivalent.

Any advice or thoughts would be greatly appreciated.

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Postby stoneyboy » Sat Dec 26, 2020 10:06 pm

Hi flinto
If you have a damp membrane across you ceiling you could use the celotex.
Presumably you do not so your best option to avoid condensation problems is to use more fibreglass type insulation but make sure your loft is cross ventilated.
Regards S
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