Loft Insulation Advice

ricardo81

Greetings,

I've recently moved home into a building made in 1890, which has a room in roof attic. I am under the impression whatever insulation I need, it will need to be breathable. I notice when looking in the crawl space that the insulation was only half done, some of the horizontal has been done, but the roof side hasn't and only part of the wall of the room has.

There are bags of unused insulation there still bagged up, "mineral fibre loft insulation" that is 100m thick (4 inches) thick. It was made by Texas Homecare for Cape Insulation LTD, it seems the former went out of business a number of years ago.

Firstly, is that kind of insulation appropriate and would its age be a factor in using it? I ask as I would likely lay it myself, but lack the knowledge to decide whether it is worth it or needs replaced by something else.

Cheers

ricardo81

FWIW the insulation indicates it conforms to BS.5803:Part 1:1979

grumbler

Age doesn't matter for mineral wool.

100mm is inadequate by modern standards.

Breatheability, AFAIK, depends on what you insulate and on the design - it's more complicated than you think.

FreeBear

Mineral wool and fibreglass insulation will be fine - The loose mat of fibres will allow moisture to pass through. Just avoid solid materials such as polystyrene and Celotex/Kingspan type polyurethane foam boards. And for heavens sake, do not have that spray foam insulation pumped in.

daivid

grumbler said:

Age doesn't matter for mineral wool.

100mm is inadequate by modern standards.

Breatheability, AFAIK, depends on what you insulate and on the design - it's more complicated than you think.

To clarify for the OP, yes 100mm is far less than you will want to put in but there is nothing wrong with using the stuff you already have. I would be going for a total of 300mm, and there is nothing wrong with layering up e.g. 3 layers of 100mm or 1 of 200 and 1 of 100... When you add layers lay them perpendicular to the layer below if you can. When/if you buy more look out for special offers from the different retailers, insulations seems to always be on offer somewhere.