Hi, I am trying to see if you have a good primer to put over plaster walls, after the wallpaper is removed. It appears that the standard idea is to put on a primer, to cover any remaining adhesive, but I like to avoid the chemicals in products like Kilz, etc. Please advise!
Toxic primers are not necessary and not better on plaster. Any coating will peel and bubble if applied over unsound adhesives. Not always right away, sometimes it happens after the second coat of paint, sometimes longer. Anything interfering with coating adhesion should be removed.
If the paper peels off in sheets then we just wash it down with Earth Clean and prime with Lime Prime.
Lime Prime reacts and bonds with the lime and other minerals in most plasters and concrete. It will also help with any mold on the surface under the wallpaper (very common).
If it doesn't come off and needs to be stripped (also common on plaster), then we wet it.
The best thing to do is strip it with hot water and vinegar.
Soak 30 min. (don't bother scraping till it's wet, you'll damage the walls).
After soaking, then scrape. If it soaks through the paper to the glue, the glue will scrape off easily with the paper and can then be washed clean with Earth Clean and hot water.
If the paper is not porous or real thick or multi layered, then we sand the heck out of it with 35 grit paper to open it up. Then soak until saturated with hot water and vinegar (or Earth Clean if something very strong is needed).
Towels along baseboard.
Canvas drop cloths.
1/2" nap roller in pail to wet walls.
Big cellulose sponges.
2-3 or 4" inch, thin taping knives to strip carefully.
Tape cracks. Use hard drywall mud for imperfections (USG Green lid is fine).
Mix joint compound and Caulk 1:1 to infill large cracks before taping. Never tape over voids. Always infill.
Prime with Lime Prime.
Top coat with Lime Seal (if something very strong is needed to seal the walls, otherwise, any paint if fine to top coat over Lime Prime).
A primer and two top coats are typical on plaster walls that were stripped from wallpaper.
Whatever materials are being used, always test in a small area before beginning job. Apply Primer and top coats in test. A non toxic painted surface should be apparent and everything should look good and smooth.
Those are the basics to strip wallpaper. Many issues arise in plaster walls such as breath-ability, insulation, what's behind the walls, calcimine coatings, arsenic coatings or additives (usually appear green hues), there's just a ton of things...horsehair plaster was common for awhile, this has special needs as well. I just do the test area and go from there. If you come across any issues I can take a look the pics if you'd like.
Sample pints are recommended for creating a finished sample in advance.
Tom Rioux founded Earthpaint after becoming severely ill as a professional paint contractor.