Firstly, thank you for taking time to read my problem and to consider any remedy.

In 2010, I bought a home that was built in 1956 with no overhanging roof; hence, it has no soffits for venting. It has two large gable vents on each end of the roof North & South and two turbines. The house is approximately 1500 sf.

In 2010, new cellulose insulation was sprayed into the attic high enough to adequately cover the joists. The cellulose insulation was sprayed all the way up next to where the roof edge and wall of the house unite.

My problem: I started noticing severe cupping of my indoor ceilings this last summer, and the roof can be seen from the outside to be cupping along with numerous nail popping.

Up in the attic, I pulled some insulation away from where roof and wall unite and noticed there is a 2-inch cavity between the wall and attic floor. I immediately felt cool air coming up and out of this gap.

My question: is this cavity/gap a ventilation property of the house that has been blocked off by spraying in the new insulation and causing possible blocked ventilation? Alternatively, is there another reason for the sudden cupping and nail popping?

Thank you for your generous advice.