This home had a tar and gravel roof on a 2.5/12 pitch. This didn’t provide any room for air ventilation. This wasn’t a problem because there was no intake and no exhaust, and the rafters were full of insulation. This is called a “hot roof” because it isn’t vented at all and has almost zero uninsulated space.
We removed the old roof and decking, installed new 2×8 rafters at a 4/12 pitch, added insulation, and then 5/8″ OSB and a shingled roofing system. This allowed room for vented soffit and a ridge vent to work together and lowered their energy usage bills!