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Loft insulation boards

Posted: Fri Jan 26, 2024 10:36 am
by Mayhem147

I live in and old house (1890's) with no loft insulation.
I'm planning to start by insulating the eaves area (I'm not sure if this is the correct term)

Can I cut to size and push Kingspan TP10 insulation boards into the area or will this cause any issue for example damp?
Is there a better way to do this?

I have added a basic animated drawing to help explain what I mean.

Re: Loft insulation boards

Posted: Tue Jan 30, 2024 10:48 pm
by stoneyboy
Hi mayhem147,
You should be fine with your proposal provided you maintain an air gap above the boards for ventilation. This assumes the roof construction is as per your diagram with roof rafters and secondary roof rafters inside them.with a gap between them to slide the boards in. This would be unusual.
It’s more likely that you are proposing pushing boards down between the rafters. There are a couple of possible problem - the rafters are not parallel so the boards won’t fit - and the chances are that you have lathe and plaster ceilings and the keys or squirts between the lathes will mean there will be a ventilated air gap under the insulation boards, this reducing or removing the insulation effect of the boards.
Regards S