Hi,
I live in a 1920s semi with slate roof and no felt lining.
I recently had a leak in my roof (now repaired) so have become somewhat obsessed with checking that my roof is OK!
When looking around for any signs of dampness, I noticed that the top of some beams nearest to the underside of the slates feel slightly damp - they are not wet as such and I don't think it's from a leak, but they don't feel entirely dry to touch either.
This got me thinking about the polystyrene slabs (roughly 2" thick) which are inserted between all of the roof timbers - they were there long before I bought the house and have been 'helpfully attached using lines of expanding foam in places across the slates and slats.
I understand that it's normal for condensation to form on the underside of slates and that ventilation is needed to keep everything dry. I assume therefore that the polystyrene may be preventing the moisture from drying, which could be causing the timbers to become damp. I'm therefore considering removing it all, but before I do I wanted to get some views...
-Has inserting polystyrene slabs 'ever' been a recognised thing to do? I know some people spray foam onto the undersides of slate tiles, which I believe isn't recommended.
-Given that the polystyrene slabs have probably been there for a very long time - do I just leave them, or remove them? and if I remove them, is it OK to simply leave the slate exposed given that there is no felt lining beneath the slate?
I don't want to make anything worse by disturbing something that has been in place for years, but at the same time, my logic tells me they are not serving any purpose and only hindering the airflow.
Welcome some advice please!
I live in a 1920s semi with slate roof and no felt lining.
I recently had a leak in my roof (now repaired) so have become somewhat obsessed with checking that my roof is OK!
When looking around for any signs of dampness, I noticed that the top of some beams nearest to the underside of the slates feel slightly damp - they are not wet as such and I don't think it's from a leak, but they don't feel entirely dry to touch either.
This got me thinking about the polystyrene slabs (roughly 2" thick) which are inserted between all of the roof timbers - they were there long before I bought the house and have been 'helpfully attached using lines of expanding foam in places across the slates and slats.
I understand that it's normal for condensation to form on the underside of slates and that ventilation is needed to keep everything dry. I assume therefore that the polystyrene may be preventing the moisture from drying, which could be causing the timbers to become damp. I'm therefore considering removing it all, but before I do I wanted to get some views...
-Has inserting polystyrene slabs 'ever' been a recognised thing to do? I know some people spray foam onto the undersides of slate tiles, which I believe isn't recommended.
-Given that the polystyrene slabs have probably been there for a very long time - do I just leave them, or remove them? and if I remove them, is it OK to simply leave the slate exposed given that there is no felt lining beneath the slate?
I don't want to make anything worse by disturbing something that has been in place for years, but at the same time, my logic tells me they are not serving any purpose and only hindering the airflow.
Welcome some advice please!