To calculate an example of exhaust and intake use 25 feet of roof ridge vent.
Roof ridge ent something eating plywood.
Since exhaust and intake must be equal 450 square inches of total intake is required as well.
Multiply it by 18 square inches the net free air per foot of ridge.
Most roofs will be sheathed in plywood at least 3 8 inch thick.
But the idea is that it would evaporate without falling down onto the insulation below.
Roll roofing is inexpensive and easy to install.
Be confident about your roof s performance.
Ways to work on a steeply pitched roof.
So much information has been devoted to the subject of roof venting that it s easy to become confused and to lose focus.
Something tells me this would be worse than the original problem 3 use a half ridge vent.
Vents evenly spaced underneath the roof provide intake.
Shingle obstructed ridge vent warning.
Something like tar paper over thin plywood hung from straps.
If when inspecting from the attic and looking up into the slot of removed plywood at the ridge of the roof you see the under side of a roof shingle either the roofer made the ridge vent a bit longer than needed or something else is going on that we d need to check from outside.
Loads will vary with the pitch of the roof.
This gives you 450 square inches of total exhaust.
As sharptooth said it will delaminate in no time if not covered.
Block the ridge vent with fiberglass in the winter.
Instead of putting the vent square on the ridge open to either side place it only on the downwind side of the roof assuming consistent prevailing winds.
Repairing leaking ridge vents.
A vented attic where insulation is placed on an air sealed attic floor is one of the most underappreciated building assemblies that we have in the history of building science.
You can use any cheap plywood or even particle board as a short term sheathing on a shed roof but cover it with a layer of rolled roofing.
Openings along the sides allow air out of the attic cooling the space and lowering your air conditioning bill.
A shallow v trough inside the roof just under the peak ridge to catch any infall.
This option appeals to me.
During the evaluation the roofing contractor will not only assess the condition of the ridge vents but he will also identify issues with shingle wear damaged flashing and more.
Roofers use a circular saw to cut a long slot along the roof ridge if there isn t one then cover it with a plastic flap as shown or a flexible vinyl matrix.
Avoiding problems with ridge vents is easy when you schedule an annual roof inspection.
That will suffice on a roof with rafters set 16 inches apart with minimal roof loads.
