I am having problems applying Behr Premium Plus Interior flat paint on
primed drywall. I am getting bubbles and sags in the paint after I roll
it on. I am used to rolling the paint on in a "W" shape, rolling again
to spread the paint, and then backrolling once more - a total of three
passes with the roller for each section I do. Now I have to roll each
area at least one more time to smooth out the paint. After that, I
have to re-roll some areas that have been down for a few minutes
because the paint is sagging. Thanks for any help.

Jim