What did you fill the holes with, Bee??? This plywood ain't AC which would have been very costly so it has a few knot holes which are one ply deep in eacjh board... Underneath is the old "asbestos" tiles that was used up until the 60s or 70s and the asbestos guy said that the best thing to do was cover it up... All the plywood is glued and screwed so everything is tight as a mouse's ear... Oh yeah, it's 1/2 inch...
Somebody said that the urethane yellows purdy quickly??? No??? Yes???