I have an extension on the barn (shed roof from one long side), we can call it a garage, which is currently completely uninsulated. I'm a bit keen to insulate it, but the question is what ventilation is required above the insulation.
At the front, I have a 3-4cm gap along the entire fascia to the air gap, so there's no issue there. At the rear, however, it is currently completely sealed (except for a vent on each side under the roof joists). (The roof consists of tongue and groove, tar paper, and sheet metal)
I'm a bit flexible on how much insulation and ceiling height is required..
The roof joists are 22.5cm. I see a few options:
1: Install a vent through the outer roof in each bay, "mold stopper." However, this requires me to drill about 10 holes as the joists are 60 cm apart and remove the new sheet metal roof to install these through the tar paper… a lot of hassle...
2. Lower the ceiling height at the rear so no insulation goes up between the roof beams in the last 50-100cm. This will create an air pocket here, and a vent on each side should then suffice? This results in a 250 ceiling height at the rear, and I'll have to economize on the insulation since it otherwise takes away ceiling height.
3. Insulate between the joists and leave x cm air gap. Drill holes in each joist to connect the air pockets to the sides… although, this likely requires a hole too large, which weakens the solid construction. Otherwise, this would have been the best option in terms of work effort and ceiling height.
It can be added that the roof beams are 3 meters from the rear to the front bearing line 45x225 cc 60. At the rear, the roof beams rest on 2 joists.
At the front, I have a 3-4cm gap along the entire fascia to the air gap, so there's no issue there. At the rear, however, it is currently completely sealed (except for a vent on each side under the roof joists). (The roof consists of tongue and groove, tar paper, and sheet metal)
I'm a bit flexible on how much insulation and ceiling height is required..
The roof joists are 22.5cm. I see a few options:
1: Install a vent through the outer roof in each bay, "mold stopper." However, this requires me to drill about 10 holes as the joists are 60 cm apart and remove the new sheet metal roof to install these through the tar paper… a lot of hassle...
2. Lower the ceiling height at the rear so no insulation goes up between the roof beams in the last 50-100cm. This will create an air pocket here, and a vent on each side should then suffice? This results in a 250 ceiling height at the rear, and I'll have to economize on the insulation since it otherwise takes away ceiling height.
3. Insulate between the joists and leave x cm air gap. Drill holes in each joist to connect the air pockets to the sides… although, this likely requires a hole too large, which weakens the solid construction. Otherwise, this would have been the best option in terms of work effort and ceiling height.
It can be added that the roof beams are 3 meters from the rear to the front bearing line 45x225 cc 60. At the rear, the roof beams rest on 2 joists.
A bit hard to understand how your roof is constructed.A Arne999 said:
Front edge? Back edge? Etc.
Can you show a section of the roof construction, with the different beams, waterproofing layers and insulation layers drawn in
so it's a bit easier to understand.
this is how it looks from the side and the question is if I can insulate between the roof beams and get air to circulate from the front edge and out on the sides by drilling holes in each roof joist. However, the holes won't be very large as I don't want to weaken the construction but currently, it's a little overbuilt so....
attempted to draw a picture.... it's a bit messy but
attempted to draw a picture.... it's a bit messy but
