water laden air from shower condenses on inside surface of metal roof cap. Then condensation flows down to duct joint/ plywood edge (at duct cut out) of bare plywood. Plywood acts like a sponge, wicking up the condensation. It begins to be big problem once outside air temperatures get below mid to upper 40's (F).
Any way to prevent condensation in first place or better way to remove vapor to eliminate problem?
2007-09-05 02:12:34 · 6 answers · asked by DannyBoy 1 in Home & Garden ➔ Maintenance & Repairs
It doesn't sound like the vent duct was installed correctly. If I understand your problem correctly, the duct protrudes through the roof, but condensation occurs on the duct cap which then drips back down on the outside of the duct and gets onto the plywood.
Starting from basics, your vent fan should be ducted outside the house, either out a side wall or completely through the roof. The penetration (wall or roof) should be completely sealed. This would prevent the condensate from reaching the plywood. You can also try insulating the ductwork through the attic. This would allow the air to carry more of the heat to the discharge point, changing the condensation temperature. The final try would be to look for a different style cap that would minimize your condensate problem.
2007-09-05 05:49:10 · answer #1 · answered by Jeffrey S 6 · 1⤊ 0⤋
Snow on the roof? dangerous,what`s strange about that? Sorry! Don`t mean anything by that comment, just that I would`nt go up there either! -- If it`s been very cold! You probably have condensation. On a cold night I would go up in the loft and check for frost on the underside of felt paper? On a warm day, and snow is melting, I would also go up in the loft and check for dripping from same area? This may give you a better idea of what`s going on! At least until i`ts safe enough for someone to check it out from above! Maybe Santa could check it out while he`s up there? Good luck with it! Merry Christmas! from Canada.
2016-04-03 04:36:57 · answer #2 · answered by Anonymous · 0⤊ 0⤋
If you have a vented ridge, you may be pulling moisture up onto the ridge cap. You may need to take up the ridge cap, and add closures or z-closure to fill the gap between the panel ribs and the ridge cap
2007-09-07 02:49:42 · answer #3 · answered by Best Buy Metals Roofing 2 · 0⤊ 0⤋
Insulate the duct or replace it with insulated flex duct.
2007-09-05 03:11:18 · answer #4 · answered by gizmoe 6 · 0⤊ 0⤋
your fart fan - commonly known as bath vent fan should have a high CFM rating ( 130 or more ) & you should let it run during shower & 5 minutes after ward to expell moisture to exterior
2007-09-05 02:25:11 · answer #5 · answered by Bonno 6 · 0⤊ 0⤋
Seal the joint!
2007-09-05 02:49:21 · answer #6 · answered by Irv S 7 · 0⤊ 0⤋