You can do either or preferably both. I usually just knock off the really bad stuff with some 60 or 80 grit, apply the Gardz with a "micro fiber" roller cover, sand again with 100 grit, Gardz again and move on.

Yeah, I would do all your sanding prior to apply anything. Applying anything to a rough surface just makes it harder to sand smooth later on.

Well, I sanded away last night and got the walls smooth. It was actually pretty easy. My question is, do I still need to use the Guardz or would another (less expensive) primer do the job? I have a kitchen and hallway that I have to strip also and am not sure if it will come off as easily and if I should save the Guardz for that?

I don't remember Gardz being that expensive. You want to use the Gardz in case there is residual wallpaper glue on the wall. The Gardz will neutralize that glue so that it does not cause your paint to crackle off the paint later (paint does not stick to glue). A normal every day primer will not work for this purpose.

glue
A strong liquid adhesive obtained by boiling collagenous animal parts such as bones, hides, and hooves into hard gelatin and then adding water.

paste would be a better term for what is left over from stripping 95% of paper

just sayin

Main Entry: paste
Part of Speech: noun, verb
Definition: glue, adhesive
Synonyms: cement, fasten, fix, gum, mucilage, patch, plaster, spit, stick, stickum

Mucilage?

Mucilage? Sounds like it should be a 'good-for-you' fiber drink. :-)

mu·ci·lage
â â[myoo-suh-lij]
Ânoun

1. any of various, usually liquid, preparations of gum, glue, or the like, used as an adhesive.

you know what I mean

I just used Gardz last night to start the repair process in the bathroom I just painstakingly stripped wallpaper off unprepared dryway (what a nightmare - I am still cursing whoever did this!). I sanded it down pretty well, but there were still little chunks of glue that I could not get off. Anyway, the gardz cost $30 a gallon, and my local store did not carry it in quarts. I used very little as it is quite thin. It did an amazing job of "sealing" that drywall and I feel alot better about moving forward with this! Some of that pesky glue actually loosened while I was applying the gardz and I scrapped it off as I went. This morning, I have a fairly smooth (well, excepted where the drywall is torn and we have to skim coat) wall and it feels like a nice consistent surface sealed from any residual glue etc.

The can says to sand, apply gardz, do the skim coat, sand and then reapply gardz. I was going to use a normal white tint primer for the second application - over the skimcoat as i think that is the advice I read on this forum. Do I need to apply the gardz over the skimcoat like the can says?

thanks for the recommendations, this seems to be a great product!

Yes, you can use a normal primer after the patching and skimcoating is done.