Roof Jack for Exhaust Vent in Existing Foam Roof
We are installing a 6-in.duct to exhaust a range hood. It must go to the roof, as the other option is more complicated (cut into stucco) The roof is an existing foam roof and we are confused about how to secure and seal the duct stack with a roof jack.
Most information about installing exhaust ducts pertains to other roof types and roofs with attic access below. The only information for foam roofs that I found indicates that the roof jack should sit upon the existing roofing. See attached specification from Dura-Foam.
My question is: in the Dura-Foam example how is the roof jack secured to the roof? Simply gravity and mastic?
More importantly, how is the duct stack secured to the roof jack? With duct tape? -- and then mastic??
Just to be clear, we cannot access the underside of the roof; that is, there is no attic access for a person to get in. We think we can extend a drill bit through the ceiling cut the 3 feet to mark the center point for the roof cut, but we did not plan to tear out the kitchen ceiling.
Thank you for your help!