Gardz is specifically made to soak in and seal up wallboard when the surface layer of paper has been removed.
Drywall mud or latex primer is nowhere near as good on that substrate, and in fact, will probably not adhere. Especially a cheap latex primer.
In addition, it will seal up any remaining adhesive pnew failed to remove. If he tries to skim coat with drywall mud over that adhesive, it will probably turn loose and fall off the wall.
Good point Tex. I failed to ask what kind of bubbles. Some look like blisters and it's just the air getting out. Looks like someone took a pen to the wall in places. Don't want someone confused which is which.
Been doing drywall for thirty years.
In that thirty years I've seen all kinds of fancy products out on the market to take people's hard earned $$$.
Simple primer will show what is going to stick or not stick no matter the condition of the surface.
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