Bagging insulation... the remedy.

[MR GUS]

Turns out the solution is perforated (to allow for compression recovery & breathability) is 250 guage polythene
so in theory you could make your own bags up..

Now what is 250 guage & where am i likely to find some to feel up!? 

http://www.mayplas.co.uk/product_pdfs/541.pdf

http://www.mayplas.co.uk/products.htm

They do a lot of kit, hopefully this info means you can gerry rig to a similar spec using some tacky carpet tape or similar.
 

[JohnS]

Is it perforated? Won't the holes affect the vapour barrier?

[Baz]

re perforations - must depend on use. The website links kept on about mushroom growing so going to be damp and need 100% sealed but in a domestic loft it needs the little perforations to let the moisture up and out or it would be sweating either into the ceiling plaster or inside the bag.

[Baz]

Just had a thought. Modern 'tarpaulin' material is utterly useless plastic coated mesh that holds water for about five minutes. There must be hundreds of them around with the owners swearing at their porosity who would be glad to get rid of them. I have a couple I only use to keep the UV off the plastic sheet underneath.

[MR GUS]

Now we need a proper image of the stuff complete with holes to gauge hole size & spaceings..