No ridge vent necessary?

steve O'Shea
1/13/2015
I'm building an uninsulated workshop. The roof plan is to put osb on the rafters, peel and stick (high temp) underlayment, 1 x strips every two feet, and then 5 v crimp. The detail I'm curious about is the ridge. The folks I bought my metal from (a roofing co, not a box store) said that I should leave a gap in osb of about 6" at the ridge. I should then run the final layer of underlayment directly down the ridge and fold it down on either side (covering the 6" gap). I should then place the ridge caps down and fasten it through thick foam gaskets that are notched out for the v's. I was assured that 5-v crimp in my application does not need a vent and that it vents on it's own out the end of the ridge. I was also told that the roofing underlayment that covers the 6" gap would not impede air from leaving the interior of the building. Although the advice giver seemed competent and knowledgeable, I'd love confirmation of this before I go against my gut.
Info @windowsonwashington.net
An informed customer is our best customer.
1/14/2015
If you aren't venting the roof, no gap. Do you want to provide for some convective air movement, leave the gap and install the vented cap.
steve O'Shea
1/14/2015
Thanks Eric, but they did not offer a vented cap. They said one does not exist for 5-v crimp due to the fact that its not necessary. This is mainly what I'm trying to confirm or deny.
Alan Ross
"Make sure its ©Watertight"
1/14/2015
Hi Steve, The peel and stick underlayment that you are using shouldn't allow for much ventilation at all. I use vented closures for my ridge cap all the time that are made for a 5v profile rib. You can order them in 10ft sections, Gulf Coast Supply in Horseshoe beach carries them. I would cut a slit in the peel and stick about 3" wide and install a vented closure along the length of the ridge. The material keeps water and pest out while letting the air vent through the material.

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