we are rebuilding a timber framed extension (not brick) 3.6m x 3m, clad in weather board, roof is obs board covered with 3 layers of felt, 100mm kingspan between joists and have 50mm foil backed board to go under(not up yet), we have a vented soffit board but there is no vent at the highest point/abutment of the roof, so the roof wont vent, can I retro fit mushroom vents? is so do you need 1x per joist space or can I fit 1x every other space with holes between joists?, look forward to any replies thanks
venting a cold flat roof
- Thread starter CHOWDER
- Start date
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Strictly you need to ensure air flow between the gaps, if you are not putting in one vent per gap (which would look stupid anyway).
If you had, say, 3 across the back of the roof, could you drill a couple of 1" dia holes near the top of each joist, so that there could be at least some air circulation between the gaps?
This wouldn't weaken the joists structurally if it was done within a foot or so of the ends.
If you had, say, 3 across the back of the roof, could you drill a couple of 1" dia holes near the top of each joist, so that there could be at least some air circulation between the gaps?
This wouldn't weaken the joists structurally if it was done within a foot or so of the ends.
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