Ventilation

 Some homeowners thinks that by limiting the attic air circulation
they are saving on his energy costs. Just the opposite is true,
of course, but you have a hard time convincing them.
Contractors take pains to use enough venting for proper
circulation. It is part of all building codes as it should be.

I once had a customer who stuffed insulation into the attic roof
overhangs to prevent the cold air from coming into the house.
Doing so closed off all the overhang vents we had installed. A
few months after we completed work he called to complain that
a part of his roof was bulging. I went to see what it was all about
& found what he had done. The lack of air circulation increased
the heat factor tremendously in the attic area, enough to push
up the plywood sheathing.
This is an extreme case but shows the power of heat energy
being able to move nailed lumber.

The interior walls & ceiling should be insulated in an envelope
fashion & all areas surrounding it should be flooded with new
air circulation.