Roofing

What material should I attach under the rafters to reduce weather/dust issues?

Anonymous user 09/03/2024 - 2.38 PM

We have a very old tiled roof, with no felt or insulation under the tiles, battens or rafters. Standing in the roof space, you can see the underside of the tiles. They've been torched, so there's lots of old mortar on the undersides of the tiles where they join, which is slowly coming loose and falling into the attic space over time. We're having the attic boarded to make some useful storage space, and I'd like to attach some material to the underside of the rafters to reduce the wind and dust into this space. I don't want to cause any condensation issues, of course, and so I don't want to use any roofing felt or other non-breathable or low-breathability materials. I was thinking of some kind of woven or mesh fabric that easily allows vapor through it, but reduces the worst of the wind and dust/mortar falling through and from the tiles. I'd leave a 200mil gap at the bottom where the rafters meet the joists, for additional protection against condensation by ensuing a good airflow through the rafters. Do this sound a sensible idea? What sort of material should I use?