Roofing thoughts if you will…
this one is at the low end of a long priority list, but due to necessary partial repairs and the current view of the sky, I need to consider future insulation make up now.
Most of the roof has bitumen felt over the commons, failing in places though.
Tiles are triple Romans, great air gap, but also very weatherproof. They’ve no need to be removed themselves.
Commons are shallow at 100mm.
Collars are about 1000mm below ridge.
It will be a warm roof, bedroom below.
Once upon a time the inside was lath on the underside of the commons. Presumably nothing more than a skim of lime.
Before we imminently replace tiles on the repaired section, I’m in two minds as to whether to add a membrane.
The end goal for this roof will be insulation between rafters. Followed by wood wool/fibre and hemp lime.
The roof height externally won’t be changing, so external insulation above commons isn’t a consideration.
Part of me is considering adding no membrane (cut out the old felt from below) and 60mm Steico protect dry boards cut between rafters flush with top face, then 50mm pavaflex batts slightly squished / sheepswool under the board to finish the in-rafter fill. Then either wood wool boards, or woodfibre, against the underside of rafters. So a solid mass of materials no air gap until under tile.
The Steico boards claim to have weather resistance and be hydrophobic, so potentially could cope with shedding the occasional bit of rain being blown in, but the tiles are in good shape so this is minimal.
Other two options are
- leave the rafter gap open, cut the felt out above, add breather membrane below and then insulate. But I lose 100mm off an already cosy roofline internally, or
- take the tiles off, rebatten, breather membrane taut over commons, and same insulation as my current plan.
Any thoughts or experience of similar?
This is the third triple roman covered roof I have, all differing historic make ups under tiles, none leaking so I’m loathe to start removing tiles for the sake of a membrane I’m not 100% sure if a necessary
getting soaked without me knowing it. And I do need a warm roof.
Cheers
this one is at the low end of a long priority list, but due to necessary partial repairs and the current view of the sky, I need to consider future insulation make up now.
Most of the roof has bitumen felt over the commons, failing in places though.
Tiles are triple Romans, great air gap, but also very weatherproof. They’ve no need to be removed themselves.
Commons are shallow at 100mm.
Collars are about 1000mm below ridge.
It will be a warm roof, bedroom below.
Once upon a time the inside was lath on the underside of the commons. Presumably nothing more than a skim of lime.
Before we imminently replace tiles on the repaired section, I’m in two minds as to whether to add a membrane.
The end goal for this roof will be insulation between rafters. Followed by wood wool/fibre and hemp lime.
The roof height externally won’t be changing, so external insulation above commons isn’t a consideration.
Part of me is considering adding no membrane (cut out the old felt from below) and 60mm Steico protect dry boards cut between rafters flush with top face, then 50mm pavaflex batts slightly squished / sheepswool under the board to finish the in-rafter fill. Then either wood wool boards, or woodfibre, against the underside of rafters. So a solid mass of materials no air gap until under tile.
The Steico boards claim to have weather resistance and be hydrophobic, so potentially could cope with shedding the occasional bit of rain being blown in, but the tiles are in good shape so this is minimal.
Other two options are
- leave the rafter gap open, cut the felt out above, add breather membrane below and then insulate. But I lose 100mm off an already cosy roofline internally, or
- take the tiles off, rebatten, breather membrane taut over commons, and same insulation as my current plan.
Any thoughts or experience of similar?
This is the third triple roman covered roof I have, all differing historic make ups under tiles, none leaking so I’m loathe to start removing tiles for the sake of a membrane I’m not 100% sure if a necessary
getting soaked without me knowing it. And I do need a warm roof.Cheers
