Had prepared walls with some type of primer for wall paper 25 yrs ago. I have pulled the paper off and repaired the walls. It seems the walls because of the repairs is taking the paint differently in areas. I think I need a primer. Are all primers the same. I am using a Benjamin Moore flat latex paint. Any suggestions.
Chris is right- and here is why.
First- did you remove as much paste as you could? very important because it will be "lumpy" and can, even through regular latex paint- reactivate and expand.
And your repairs with mud/spackle will absorb differently than just painted walls.
What Gardz ( water base) or Cover Stain (Oil based) will do is seal in both and make a vapor barrier that will not allow moisture, either from the top coats of paint or the atmosphere- to penetrate and cause trouble later.
"It's better to come here with questions before you screw up than to come here after and ask how to fix them."- JS