Here's what I recommend in a few words...you may not need THIS much info, but I'm sure you can pull what you need!
1. Paint the damaged areas with polyvinyl acetate glue (sold as LePage's BondFast, Weldbond or Elmer's Wood Glue) diluted with enough water to make it into a paintable consistancy. Allow this glue to dry. As it does, not only will it glue all the fibers together so they won't swell and lift if they get wet, but it'll also act as a good moisture barrier for the dry paper underneath.
(PVA glue is not water proof, but only water resistant. This is beneficial here because a subsequent coat of wet plaster will re-activate the glue, causing the plaster skim coat to adhere better to the wall.)
2. After the PVA glue is dry, apply self adhesive fiberglass mesh drywall tape over the damaged areas. Apply two coats of fiberglass mesh drywalling tape with the rows of the second coat running perpendicular to the first, and painting over the tape with dilute PVA glue after each coat. The fiberglass mesh will replace the strength lost due to the missing paper, and the dilute PVA glue will bond the tape to the drywall as well as the orginal paper was bonded to it. Allow the PVA glue to dry after each coat of tape.
3. Using an adhesive trowel with small notches, spread joint compound over the repairs with the notched edge of the trowel and allow to dry. Once dry, hold the adhesive trowel upside down and fill in between the notch ridges with more joint compound, thereby establishing a thin but uniform skim coat of drywall mud over the repaired areas. Premixed joint compound will be very thick when you buy it, so don't be scared to thin it with water to make it into a more spreadable consistancy. I use an electric drill with an old kitchen mixer blade and a metal can to do this in.
4. Holding a bright light next to the wall to exagerate the rough areas, sand the joint compound smooth AND/OR apply more joint compound to areas that need it. Sand with sand paper if you're getting paid by the hour. The dust will clog up the paper, and you can waste a whole day getting nothing done. If you're working for yourself, use a 100 grit sanding screen in a hand sanding tool, and slip a 3M green nylon Scotchbrite pad (of the kind sold in grocery stores for cleaning pots) between the sanding screen and the tool. This will allow the dust to pass through the screen where it can be removed from the nylon pad by holding the tool horizontaly about 1/4 inch from the wall and tapping the tool lightly against the wall so the dust falls out the side of the tool.
5. Wipe the dust off the smooth plaster with a dry rag, prime and paint. What I don't like about primers is that they're made thicker so they don't spatter as much when used with a roller. The problem is that being thicker, they don't penetrate as well into bare drywall mud, and only form a film over top of it. This is all you need most of the time, but if you subsequently put masking tape over that primer and pull it off, it'll pull the primer film right off the plaster. What I like to do us use a roller to paint dilute PVA over the bare plaster and allow it to dry. This glue gets absorbed into the bare plaster much more readily and glues all the gypsum grains together as it dries. Use a roller and go over it ONLY once or twice. If you want to go over it again, wait for the first coat to dry, then go over it again. Plaster will become softer if it gets wet from this dilute adhesive, and you can muck up your smooth surface at this point if you're not aware that the plaster is soft. After the glue dries over those bare plaster patches, then prime and paint.
Or you can click
HERE to view these instructions on the web.
Mike
Linear Mode
