ErikVann
Silver Member
What's the intended purpose of the venting? Flat roofs don't typically have vents. I agree with Builderml, spray foam is the way to go. Allowing air flow under your flat roof will be inviting several moisture related issues. Roof venting works as a chimney effect air moves up from the soffit vents and exits the ridge vent. This keeping the roof surface cool in the winter time so that there is no melting from heat loss for the structures, in The summer it vents hot air generated from the roof surface thus keeping the attic cooler.
In a flat roof situation you are unable to rely on a chimney effect to move air through the vented space. You will develop mold and sooner than you think the osb will deteriorate. Osb is particularly susceptible to rot caused by atmospheric moisture condensation. If you can't swing spray foam use rigid foam board and make absolute certain that you do an excellent job of sealing all joints and terminations.
In a flat roof situation you are unable to rely on a chimney effect to move air through the vented space. You will develop mold and sooner than you think the osb will deteriorate. Osb is particularly susceptible to rot caused by atmospheric moisture condensation. If you can't swing spray foam use rigid foam board and make absolute certain that you do an excellent job of sealing all joints and terminations.
