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I’ve been working on a flat-roofed 1880’s Italianate house that has been extensively re-built prior to my coming onto the job.
It’s got an all-new thermal envelope consisting of (from outside in) claps/plywood/stud bays w/FG/ continueous layer of foil-faced polyiso, taped at seams/1x strapping/ blueboard and plaster.
The ceiling assembly is essentially the same as the walls, but with a vent space above the FG. There are 2″ round vents at each end of the rafter bays cut into the frieze boards. There has been a lot of condensation damage at the locations of the fan/light/heat units in the bathroom. The architect says it’s lack of proper ventilation and that the only solution may be to redesign the house to incorporate a pitched roof that can be better ventilated.
I’ve suggested just removing the recessed fan/light/heat units from the ceiling and seeing if that solves the problem. They are not airtight. It seems to me that they are probably dumping a lot of moisture into the ceiling, creating more problems than they are solving.
Are there airtight FLH units available? Is there any advantage to going with a unit in the wall rather than the ceilng? The walls are balloon framed and open to the rafter bays, so that would seem to just relocate the problem to me.
Any thoughts?
Steve
Replies
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I've been working on a flat-roofed 1880's Italianate house that has been extensively re-built prior to my coming onto the job.
It's got an all-new thermal envelope consisting of (from outside in) claps/plywood/stud bays w/FG/ continueous layer of foil-faced polyiso, taped at seams/1x strapping/ blueboard and plaster.
The ceiling assembly is essentially the same as the walls, but with a vent space above the FG. There are 2" round vents at each end of the rafter bays cut into the frieze boards. There has been a lot of condensation damage at the locations of the fan/light/heat units in the bathroom. The architect says it's lack of proper ventilation and that the only solution may be to redesign the house to incorporate a pitched roof that can be better ventilated.
I've suggested just removing the recessed fan/light/heat units from the ceiling and seeing if that solves the problem. They are not airtight. It seems to me that they are probably dumping a lot of moisture into the ceiling, creating more problems than they are solving.
Are there airtight FLH units available? Is there any advantage to going with a unit in the wall rather than the ceilng? The walls are balloon framed and open to the rafter bays, so that would seem to just relocate the problem to me.
Any thoughts?
Steve