Explain how you would vent a shed roof please I am a little slow, drank to much freon in my days;-)
I don’t know how this one was constructed.
But an off ridge type vent would work with vented soffit.
There are many ways to do it. Here are a few.
http://www.finehomebuilding.com/CMS/uploadedImages/Images/Homebuilding/QA/hb099QA01-01_lg.jpg
http://www.quarrix.com/wp-content/uploads/2012/05/Tri-VentShedIllustration.gif
That would be nice but I have never seen one built that way how many have you seen
The sheathing and the lumber require ventilation as well. The plywood (If used) can delaminate without it.
Well, let’s pretend the garage is not open to the remaining area of the attic. You know full well many are built like that. Let’s say it’s even a detached garage. Would such a garage attic need cross-ventilation?
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I see shed roof vents sometimes. Not frequently though.
The standard answer is yes but the only reason I can think of is to reduce heat in the summer. I believe there is some question as to the validity of the long held belief that venting reduces the temp of shingles. Other reasons for venting, like keeping the space cold in winter due to heat loss from below or removing moist air, don’t apply because a garage is not typically conditioned.
The problem is this scenario is not a garage with closed walls, it is open and that airflow across the ceiling can reduce heat as well, assuming that’s even necessary. All the other reasons for venting related to having conditioned space below don’t matter.
Guess different strokes for different folks because in the 17 years of inspecting in Okla I have never observed a shed roof with vents. Never.
As for garage attics being separate from living area attics, does not happen here. Garage ceiling drywall is fire rated that is all you get
I would agree a detached non-conditioned garage attic should be considered as any other enclosed building ventilation is needed to help preserve life of the shingles.
I have a hard time wrapping my thoughts around a shed roof not enclosed needing ventilation because of the heat transfer capabilities between the shed ceiling and the open air. So Personally I say no defect if not present. But I do have a open mind convince me I’m wrong
I agree with your thinking on venting. My personal belief is the shingle MFG harp on this simply as a means to disclaim a warranty to some degree.
I have said this before I like roofs and have become a student of shingles over the years. My close observation of shingles on non vented attic older homes that just had no vents installed from the git go V/S homes with nice properly spaced soffit vents including ridge vents, wind turbines and or mechanical venting had very little difference in their useful life.
We in Okla experience four full climates and in my life time I have observed outside ambient ranging from -25 degrees to 114 degrees. In my opinion the the highest reason for shingle failure not including hail is not the temp of the attic but shade, shingles in the shade do not dry properly following a rain and often have growth/moss that destroys shingles faster than a non vented attic does.
I make this statement in rebuttal to the guys that don’t walk a roof ;-)
Down with pole cameras, binoculars and lazy inspectors.
Become a roof monkey we are in demand;-)