What is the proper method to prepare drywall for painting?

Question

I have a 25 y.o apartment with paint that peels off in large sheets. If I repaint it, I would like to understand why it is peeling so as to avoid future peeling. Maybe there is a diagnostic to identify root cause?

Answer 1

My bet is there's something in the old paint that's preventing good adhesion for the new paint. It's possible they used an oil-base indoors, or the paint had some chemical that messes with the latex you're likely using.

What I would do is buy an oil-based (mineral spirit cleanup) primer (like original Kilz) and prime the walls. Oil-based primers do a superb job of providing a "glue" layer for your latex to grab onto. Take a small area and test this hypothesis.

If that still fails, the next best thing is to put new drywall over the old and then paint fresh drywall. Obviously more expensive (and you'll need landlord permission), but you'd be guaranteed no paint problems.

Answer 2

The most likely cause is improper preparation of the original surface. The previous painter (or was it you...?) neglected to do one or more of these things:

• use appropriate primer (this only applies if it was a bare surface)
• sand properly (critical if the previous paint had any sheen/gloss)
• clean thoroughly

You need to strip every bit of poorly bonded paint, then prepare the surface with one of the methods listed above.

Don't listen to those who say "you can't use latex/acrylic over oil"; you can if you prepare the old surface properly (sand). Also, there is nothing wrong with using indoor oil-based paint indoors; I wouldn't because modern high quality acrylic/latex paints perform much like the oil paints of yesteryear.

Don't put too much stock in "miracle" primers, they work OK for trouble surfaces but have their own drawbacks (like clean-up with volatile and flammable solvents, odor, etc.)

This will likely call for some labor, but 99% of any paint job is the preparation. Always use professional grade applicators and high quality paint products.