A.Builder Mike Guertin
responds: The short answer is yes. I know that
venting hip roofs adequately can be difficult, and
that many people think that the relatively
unobtrusive ridge vents are a better aesthetic
option than a bunch of unsightly mushroom
vents.
However, I’m not a fan of using ridge
vents along hips. I installed ridge vents on the
hips of two homes 11 years ago. About six months
after the homes were complete, both homeowners had
water stains on the second floor ceilings. I found
the fiberglass insulation damp beneath a couple of
the hips, and I could see where water had dripped
along the hip rafters. I thought the leaks were due
to a particularly severe thunderstorm and figured
it wouldn’t happen again. But two weeks
later, during a moderate storm, the leaks recurred.
I removed the hip vents and haven’t had a
problem since.
My present roof venting strategy is to use a
continuous soffit vent (either a strip vent or a
fully vented vinyl soffit), and to use a ridge vent
on all true ridges. (I haven’t had any
callbacks from leaking ridge vents installed on
actual ridges.) Some ridge vents work better than
others. I think ShingleVent II by Air Vent is
better than many of the others. I’ve found
some of the roll type vents subject to installer
errors that reduce the net free vent area.
On a hip roof that lacks enough of a ridge for
adequate venting, I install roof vents (mushroom
vents) cut high on the roof slopes that
aren’t likely to be viewed.
One of the reasons for installing attic venting
is to remove moisture vapor that can condense on
roof framing, potentially causing rot in cold
climates. If you stop moisture from getting into
the attic in the first place by tightening up the
ceiling, you can reduce the need for attic venting.
Moisture " piggybacks" on the air that leaks into
the attic. The biggest air leaks you’ll
find are at attic access panels or pull-down
stairs, standard recessed light cans, regular light
fixture electric boxes, hvac ducts and chases,
whole-house fans, and the spaces around pipes and
wires that run through the top plates of walls.
During new construction, these air leaks are easy
to address.