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Discussion Starter · #1 ·
Hi all. First post here. I'm a property manager who buys income properties nobody else wants, fixes them up, and tries to put a little food on the table in the process.

Anyhow, spotted frost in an attic.

DETAILS: Affected area is above a bathroom. Outside this bathroom there is no soffit (rest of house has soffits, but this room is bumped out.)

At this point I am sealing recessed cans etc but am still concerned that the attic space above the bathroom has little to no air flow along the decking because of the lack of soffits. Worth noting that the rest of the soffited house has no frost.

QUESTION: Is it possible to generate air flow along the affected decking where there are no soffits?

SPRAY FOAM: What if I spray foamed the un-soffited rafters & decking? Total of maybe 8 rafters My thinking is that doing so would prevent the air in that section from condensing onto the "unventilated" decking. This air would not be any less stagnant, but at least it wouldn't condense onto the cold decking and just slowly move across foamed rafters, over to ventilated decking where there is proper soffit and box ventilation.

BOX VENTS DOWN LOW: What about putting box vents down low on the roof in that section? Would they allow air movement in any way similar to soffit-to-vent flow?

Thanks in advance for any input.
 

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Is there a shower in the bathroom? Fart Fan? Is the attic above the bathroom isolated from the rest of the attic or is it part of the same? Insulation on top of the lid of the bathroom?

Soffit has nothing to do with it
 

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Discussion Starter · #3 ·
Yes shower, fan. Attic not isolated. Is insulated & vapour b. There's no question that the recessed lighting cans and fan need sealing.

The attic hatch is also in line with the frost area. Spotted a 1" gap where hatch is framed & foamed it.

You're saying that with all the other soffit intake ventilation, that the soffit is not the issue. Would be great to think that just addressing ceiling leaks will address the problem.

Thanks for input!
 

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Boondockian
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Is the fan vented outside or just dumping the humid air into the attic? I've seen that more times than I can count. Your getting off lucky if its just frost and no mold if thats the case.

Since you say this bathroom isn't the same as the rest of the exterior. I suspect it was a later addition which was probably done by a HO or the lowest bidder who more often then not seem to dump the moist air from the bathroom into the attic resulting in the conditions you describe.
 

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Discussion Starter · #5 ·
Bath fan vents laterally to exterior wall. No frost where bath vent exits.

BTW Another thing on my list is venting that fan vertically but that won't happen till Spring.

As for being an addition. Room is second story room, and it is bumped out only say 16 inches from the rest of the house, so the room is definitely part of the original build. Doesn't explain they designed the house this way, other than for aesthetics. Dumb IMO.

Thanks for reply.
 

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Is the ductwork insulated. I always use flexible insulated ductwork in unconditioned space.
Is there a way to cut some soffit vents or a vented facia. I don't think foam will help unless you do the whole roof. It may just move the problem to another area of the roof or condense on the foam as it will still be an un-insulated space. Good luck.
 
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