I inspected a small house by a lake today that has no insulation on the roof or walls. I have seen many lake side houses poorly constructed to be used a few weekends a year. Typically the issue is when someone buys one of these houses to live in year round. I just about over looked the fact the walls and roof were too thin to have insulation. Typically there is no attic so insulation is limited to the rafter thickness. My first red flag was I scanned the ceilings with my thermal camera and the interior surface was around 89 degrees. The outside temperature was about 75 degrees, then while thinking what the hell is going on I could see the interior roof surface was the same as the underside of the roof over the deck looking out the windows, see the picture below. Looking closer at the roof soffit, which was not enclosed you can tell the the 1 ¼ bead board was all there was. Then I went to a door frame and and done the math the walls were 2 ½" thick, one layer of 1 ¼ bead board on the outside and one on the inside, no insulation. The reason I bring this up is this is so rare anyone could have missed this so put this in your brain as the impossible is possible.
I saw the varnish on the under side of the interior roof was bubbled up, which now makes since. The roof got too hot causing the varnish to bubble up.