I am working on converting a small agricultural barn made of granite stone into a dwelling with vaulted ceiling (for the head height upstairs).
The pitched roof is in a very good state as it was redone 15 years ago. It's made of slate, bitumen membrane and rafters are every 400mm. Ridge is traditional clay tiles bedded in mortar.
My plan is to insulate the roof in between and below the rafters leaving a 50mm gap but I am concerned with the ventilation gap at the facias (and ridge).
On one side there is a 12-15mm gap between the wall plate the membrane but on the other side they left no gaps at all. The last row of tiles meets the corner of the wall plate and pinch the membrane. See picture attached/below.
My questions are:
- What's my solution here? How can I achieve adequate roof ventilation at the facia?
- Do I need a dry ridge (or vents) to ventilate at the top or a continuous gap all across will suffice?
- Would 12-15mm gap at the facia with a 50mm gap above insulation be enough?
- Will a VLC not stop condensation or at least help if the vent not as good as it should be?
The pitched roof is in a very good state as it was redone 15 years ago. It's made of slate, bitumen membrane and rafters are every 400mm. Ridge is traditional clay tiles bedded in mortar.
My plan is to insulate the roof in between and below the rafters leaving a 50mm gap but I am concerned with the ventilation gap at the facias (and ridge).
On one side there is a 12-15mm gap between the wall plate the membrane but on the other side they left no gaps at all. The last row of tiles meets the corner of the wall plate and pinch the membrane. See picture attached/below.
My questions are:
- What's my solution here? How can I achieve adequate roof ventilation at the facia?
- Do I need a dry ridge (or vents) to ventilate at the top or a continuous gap all across will suffice?
- Would 12-15mm gap at the facia with a 50mm gap above insulation be enough?
- Will a VLC not stop condensation or at least help if the vent not as good as it should be?
