I messed up my walls, bigtime

While sanding poorly patched walls (with many layers of old paint on top) I found that the paint had lifted up so I srtarted tearing it off. Before I knew it I had torn like 5ft areas of paint and drywall paper off. Now how do I fix it?? And do you have any tips for fixing those bad patches in the furture without ripping the walls apart??? And, what make paint lift up, and/or not stick? HELP

 

Before you repair any exposed gypsum you will need to coat it with a solvent based primer - this will prevent the moisture in joint compound or latex paint/primer from reacting with the gypsum. After the primer is dry, skim coat the affected areas with a thin coat of joint compound. It may take more than 1 application, sand as needed.

Latex paint can be difficult to sand - especially on drywall. Often it is preferable to float a coat of mud over the bad patches and then sand them smooth.

It is hard to say without seeing it what caused your problems but it may be that aggressive sanding went thru the j/c and some of the paper. Once the paper starts to peel unless you can stop it by cutting a line with an utility knife you can usually just keep on peeling the paper off until you reach the end of the board.

 

A solvent based primer, or I can recommend Zinsser's "Gardz"
Gardz was designed for this type of problem and works well

It will turn the soft paper hard enough to apply joint compound (with large putty or "taping" knifes) to fill in the repairs

After the joint compound is smoothed in, it will need to be sanded smooth, dusted, and primed again before painting (regular latex primer or Gardz can be used)

 

As far as "what makes paint not stick" on an interior goes...

A lot of different things, almost all of which have to do with improper prep:

Moisture (the surface must be 100% completely dry before painting... if painting a bathroom, don't take any showers or baths there for a week before and after)
Contamination (grease, hairspray, cleaning chemicals. TSP and a thorough rinse should be done before painting in messy areas)
Dust (sloppy job of vacuuming, tacking, wiping, etc. after sanding, or just general dust)
Lousy paint (Behr from HD or AmTrad from Lowes, or a low-end paint from pretty much anybody)
Lack of primer

SirWired

 

This sounds strange... the only time I've experienced anything remotely like that was on walls where someone had skimmed and painted over wallpaper that was installed on top of old plaster and lathe.

Is that possible?

 

Absolutely possible