What's the Best Approach?

March 2007

Your customer has removed the wallpaper in a large area that includes a stairway, hallways, a foyer and a small room. You will need to skim coat the entire area to repair the walls. There's little damage to the drywall surface; most of the top layer of wallpaper has been removed. There shouldn’t be any moisture problems from the mud causing the glue to separate from the wall surface. What’s the best approach? Is a 12" knife large enough?

I’ve repaired more of this than I like but the best way I’ve found, mainly for larger areas, is to first roll a coat of shellac on the stripped areas. This will soak into the paper and cause it to bond to a hard surface. On extremely separated papered areas it may take two coats. When it dries I usually skim the walls with a quick-setting compound and then a finish coat with a topping finishing compound. You may get a very small amount of bubbles; if so, cut them out, touch up with quick set, then finish coat. I’ve tried to just skim the walls with quick set or topping but it seems to lift the paper and create a large number of bubbles and blisters. When that happens you have to sand cut and skim many times to get the same results.
—Kirk Lewis, President, Kirk Lewis Drywall L.L.C., Gladstone, MO

I would use Durabond with a 14" knife and apply a skim coat for my first coat. There always is a little glue residue that will cause the surface to bubble up especially after paint is applied. The Durabond will prevent the bubble-up. After the Durabond has set, I would take my 14" knife and skim the surface with topping and lightly sand, making the wall ready for paint.
—Jonathan Diepstra, Estimator, The Bouma Corporation, Grand Rapids, MI

We never mud over glue. The reaction is so adverse that you can never be sure of the bond. Removing all glue with pump sprayer, hot water and paste removing soap is the answer. Spraying light coats of the solution on the glue until you can feel it breaking down is the point where you begin scraping off and disposing. You can sponge off the remaining residue. This greatly reduces skimming, sanding and mess.—David E. Chokey, Vice President, Sharp Interiors, Inc., South Bend, IN First, because wallpaper is typically a bear to get off—scraping, release fluids, steamers and a lot of vulgarities, here’s a better idea: Skim coat the paper (especially if it is installed over plaster) with drywall compound. This holds moisture at the paper instead of it being sucked through the wall and dissipated. Once the paper is removed—by whatever means used—roll an adhesion intermediary over the whole area and plaster it with a skim coat of veneer plaster or drywall compound. A plasterer would use a trowel, a drywaller a knife. A wider tool—up to a limit—is better because there are fewer overlap trowel marks.
—Rob Aird, President, Robert A. Aird Inc., Frederick, MD

Step 1: Start off by removing as much loose paper as you can with a 6" knife. Step 2: There are a few layers of brown paper that will blister if not removed. We use 60 grit sandpaper to sand off the top layer of paper. It will shred it, leaving a firm surface that will not blister. You can be firm with the sanding and it will not damage the base surface that you are trying to reach. Step 3: Coat nails (if popped) and fill larger holes that won’t cover with two coats. Step 4: Roll on all-purpose mud and trowel smooth. Light sand when dry. Step 5: Roll on topping and trowel smooth. Sand when dry.
—Rick Brown, President, Advantage Drywall Systems Inc., Orange, CA

Yes, the skim coat will take care of this problem. I use a 12" knife. It is large enough to do this project. I like to use 45-minute quick-set joint compound for faster drying.
—Francisco J. Vargas, Vargas Paint and Texture, San Antonio, TX

We [would] request that the painter roll a coat of KILZ primer over the surface to seal it. You should scrape the surface with a knife before you start to skim the walls. Proceed to skim coat the walls. Try to skim it tight, all in the same direction (left/right), then do the same for the second coat but in the opposite direction (top/bottom). You will get chatter on the first coat but by pulling the second coat in the opposite direction, you fill in the chatter.
—Leon Kerns, Superior Interiors Inc., Boise, ID

Try using Plaster Weld by Larsen. It is a pink weld that works very well. You must let it dry thoroughly, possibly overnight.
—Gregg Pollock, Pollock Plastering

Skim coating is correct, but I would add a sealer before and after skim coating. You could also use a 14" knife.
—Dale L. Tucker, Owner, Acoustics, Boise, Idaho

First you must remove all the glue from the wall, use water as hot as you can handle with a little ammonia in it (4 oz. ammonia to 1 gal. water). Next, Spackle all the bad spots in the wall and let dry, then use "First Coat by USG” and "paint” the "first coat” on the walls where you need to skim coat. First Coat is a little pricey but it will save time on application and finishing and helps prevent, cracking and scaling, which is so common with "regular” skim coating.
—Jason Wein, Carpenter, Reading, PA

I would apply first a high quality primer to the wall. This would ensure you would see all potential problems that might occur and allow a better surface to apply joint compound. A 12" knife is sufficient.
—Eric Bragg, President, Bragg Drywall, Inc., Madison, MS

We would scrape the wall to be sure all loose wallpaper material is removed, roll draw tight over the surface to be assured that there is no separation or bubbling of the drywall paper. Skim two coats of an easy sand product. If that does not quite give you the smooth level surface you need, add one more coat of an all-purpose mud, sand it, and it is complete. A 12" knife or hawk and trowel should be a good choice to do the job.
—Jeff Manick, General Superintendent, Olympic Wall Systems Inc., Minneapolis, MN

Thin the joint compound slightly (not too thin or you’ll pull it off as you work with it). Roll it on with a paint roller. Then pull it tight with a knife. A 12” knife will work fine.
—Derrick S. Simpson, Owner, Simpson’s Interior Finishes, LLC, English, IN

You’re dreaming if you believe wallpaper has been removed with little damage to the drywall surface and you don’t expect moisture from the mud to cause the glue to separate from the wall surface. Even with "most” of the top layer of wallpaper removed, that last little bit of paper will come back to haunt you unless you roll on a stain-killer type of paint (such as KILZ) before applying a skim coat of Spackle. A 12” knife is sufficient since it’s not how large a knife is but how you use it!
—John Lockburner, Owner, Lockburner Drywall, E.S.Q., Branchville, NJ

The way I would do this job: 1) install covering; 2) install 1 coat of KILZ Primer; 3) install Larson’s bonding agent; 4) coat wall with all-purpose mud, then embed Senergy fiberglass mesh into all-purpose mud on all areas; 5) lightly sand and install second coat of all-purpose mud over all areas; 6) lightly sand and install final coat of finish mud over all areas; 7) finish sand with 300 watt light; 8) clean up; 9) go home and sleep well at night because you did everything right. Is a 12” knife enough? Not for some areas. We might use any tool from an 8’ plaster rod down to a 1” knife; my personal favorites are a 12”, 6”, 4”, 1” knives and a 22” plastering trowel. This is one of our typical jobs although usually we are working over plaster or a combination of drywall and plaster.
—Loren Smedberg, Owner, Professional Plastering, Seattle, WA

If the wallpaper is not removed correctly and/or if the drywall was not prepared properly for the wallpaper, then you will almost have problems. The worst part is that you will not know until you paint and then it’s too late—the work has been done and it will be hard to redo it. The best approach I have found is to 1) prime first; 2) cut out all areas that have bubbled/pulled the paper up; 3) fiberglass all bad areas; 4) apply two tight coats, allowing them to dry between coats; 5) prime again; 6) make repairs as needed; 7) retexture to match. Can use 10” or 12” knife or whatever you have. Coat all wall, pull fairly tight.
—Pat Meadows, Owner, Pat Meadows, Post Falls, ID