Bath fan ductwork - material and insulation (revisited) -
First, apologies if this should be under the "general questions" category
I saw some information from Riversong in response to a bath fan duct question asked quite a while ago (posted by Chris Johnston - Thu, 08/26/2010 - 14:57). The essence of the response was that plastic duct (glued, sloped) was somewhat insulative, and condensation would drip out (sloped out to vent cap) via the 1/4" per foot slope.
Still dealing with (what I hope is) the tail end of the coldest winter in probably 30 years here, so the 'insulative" thing kind of peaked my interest. I hope I can ask for a sanity check on this almost 4 years later - is this still the Riversong (or collective GBA) wisdom?
Reason I ask is that I just 'fixed" my smooth metal bath exhaust ductwork (I admit I botched the slope and got some water dripping into the house in Feb). In the repair process, I decided to replace it with light PVC with glued joints (to make it watertight end to end) and sloped to the gable wall, and I also pulled a light insulation sleeve over it (box store stuff @ R4 or R5 best case) . I keep wondering it that is enough insulation for the cold Canadian winters, like this year (ouch) as I haven't had a chance to let it "soak" yet (pardon the pun - next winter will tell, I suppose) but I'd like to get this project finished with some confidence now. For me, a few drips == a huge worry.
FWIW I read about the "reversed Riversong truss" concept here a while ago, while doing the retrofit on my kitchen ceiling last year - and stole the idea. Excellent - so now I gotta respect the advice here even more. Thank you.
Posted Thu, 03/13/2014 - 16:00
Edited Thu, 03/13/2014 - 16:04
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