Lining a loft

[Strud]

I have a loft space which is very dirty, but i want to use it for storage.
It has 8" fibreglass insulation, which i plan to overboard using loft legs.
My main concern is the undertile felt which is hanging down in shreds.
Can any one suggest a way i can line the inside of the loft space to provide a clean storage space?
I believe there would be an issue with condensation if I make it airtight, so presumably i need to use something vapour permeable.
Any suggestions welcomed!

 

[freddiemercurystwin]

Breathable membrane stapled to the underside of the rafters, you'll be able to order some on eBay.

 

[big-all]

i personally dont like legs as the dont spread the load unlike say 4x2 timbers at right angles
also iff you have 2 parallel timbers 400mm apart the unsupported span is 400mm
if you have legs 400mm apart and spaced at say 400mm the unsupported span is now the diagonal distance or around 45% more distance on the span at around 580mm

 

[^woody^]

And start at the top so that the laps are correct and all the dust dont fall out over your stuff