I've seen plenty of postings that one should not vent bathroom fans to
soffit or ridge vents. I completely agree about not using the soffits.
But how about using some blue foam, or other material, and making
some sort of 4" round pipe to ridge vent adapter. Think of all the
sheet metal HVAC adapters at home centers. But I'm thinking of just
fabricating something that custom fits my roof/ridge vent at one end
and a 4" round opening at other end. I can purchase a 4" sheetmetal
colar to make the round opening in the foam. This would force 99% of
the moist bathroom air directly out a portion of the ridge. The foam
adapter would protect the roof sheathing from moisture, plus it's
easily built on site.
Downfalls? reduced ridge ventilation for the attic - but I doubt
enough to have any impact
Appreciate any comments...
I don't think I would want to do it. However if you insist remember
that ridge vent is not open and has a fairly high resistance at the air
speeds a vent fan would be using so you would guess you would need a few
feet of vent in order to get something close to the efficiency of a
I might add that most ridge vents I have seen have exposed wood surfaces
and that warm moist air would damage the wood deck. You would need to make
some accommodation for that as well.
I had not thought of the air flow resistance of a typical ridge vent -
good point! Maybe that is why many posts on this topic do not
recommend the somewhat common practice of simply stapling/hanging the
fan's exhaust pipe near the ridge vent.
I was just hoping to avoid putting a hole thru the roof to install a
typical roof cap. I'm very handy, but I stay off the roof these days
:) Guess I'll pay a carpenter to go up and do it :) Another option,
if I want to do the work, would be to install a wall vent. At least I
can get to that from the outside with a ladder. Easier for me to
inspect/repair should it ever leak too...
I had a bath fan mounted to a attic vent (the 12" square kind
with the 6" hole). THis worked for several years but then I
found that I burned out the fan motor. I replaced the fan motor and
after a few years burned that one out as well.
I investigated the whole system and found that the attic vent had a
screen inside it that is used to keep the bugs etc out. Over the
years this screen became clogged with lint etc from the bathroom. So
the fan motor was working extra hard to push the air through the
clogged screen. I also found that the flex duct pipe that I had
going from the bath fan to the attic vent did not have insulation etc
on it so the moist air would condensate in the duct and actually run
back into the fan and eventually dripping on the bathroom floor.
I just replaced the whole system with a direct line over the attic to
the soffit area with a vent port out of the soffit. This duct is
insulated and is only about 5 ft long (while the old system - duct
was approx 12ft long) I purchased the vent port from a friend that
does HVAC work. It made specifically for venting fans in soffits and
actually "twirls" the air as it leaves the port (grill).
This twirl effect causes the air to be directed out away from the
I think this system will work much better than the original
-no screen in the system to clog up
-no vent on the roof (got covered in the winter with snow)
-the vent port is close to a outside deck so I can keep an eye on it.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.