Wall Prep Ahead of Wall Re-Do

This wallpaper in a Houston Heights townhome’s breakfast area was hung by “the contractor’s guy ” and he ran into some problems. First, I suspect the wall had not been adequately coated with a primer designed for use under wallpaper . This may be a large part of why the paper has come loose from the wall in places, and shrunk and gaps at the seams.
The wallpaper is an old-fashioned British pulp material , which is quite different from the non-woven material that this company usually prints on. If the installer was not familiar with hanging a pulp, yes, he can have a tough time of it.

There are other issues that the homeowner is unhappy with, such as tears, slices, patches, and, of course, these un-stuck seams. I’ve posted more pics previously, if you can Search to find them.
My task is to get the paper off and then prep the wall for hanging new material.

Most of the paper pulled off the wall easily. But there were areas where the guy had used a stronger adhesive to try to hold the edges down. Those would not come off the wall without causing damage to the wall. So I pulled off the top, inked layer and left the paper backing on the wall.
This stuff is porous and will bubble when coated with a water-borne primer , and with wallpaper wet with paste.

So I sealed these areas – I sealed the entire wall, in fact – with Gardz (by Zinsser ). This stuff is pretty incredible. It’s a thin, watery primer / sealer that soaks into the surface and binds loose components together, then dries hard and solid .
Latex paints and other water-based products (usually) won’t penetrate it, so won’t cause the underlying material to re-wet, expand , and bubble .
Just a note … due to pandemic and other supply chain related shortages , Gardz has become difficult to find. This can was about 1/4 full and I had it sitting behind my trash can, intending for weeks to toss it out. Now I’m glad that I procrastinated!

Once the Gardz sealer was dry, I skim-floated over it with joint compound , a.k.a. ” mud .” In most areas of the wall, my skim coat was as thin as possible, but I did have to make it much thicker over the areas with the paper backing stuck to the wall.
I set up three fans , and also used my heat gun , to get the smoothing compound to dry. I like the Plus 3 version made by the Sheetrock company. It sands easily and doesn’t make too much air-borne dust.
It took a couple of hours to dry. Then I sanded it smooth , vacuumed up the dust with my Shop Vac , used a damp sponge to get residual dust off the wall , and then let the wall dry once again.

Finally I applied a coat of my favorite wallpaper primer, Pro 977 Ultra Prime by Roman. I used a paint roller to roll it on to the main areas, and an angled trim brush to cut in around the ceiling and moldings.

Here is the wall all smoothed and primed .
Originally I had planned to strip , prep , and hang this half-wall all in one day. But ended up the prep took more time than I anticipated (about 8 hours ) , so we’ll let the primer dry overnight and save the wallpaper installation for another day.
The wallpaper pattern is called Strawberry Thief and is by the famous William Morris designer from the very early 1900’s . I’m sure seeing a surge in interest in his patterns, particularly this one. Do a Search to see other jobs I’ve done with it.

Danger Signs of an Unstable Wall Surface

These nails were holding picture hooks to the wall. The hooks had an adhesive backing. When they were removed from the wall, chunks of latex paint stuck to them and pulled away from the wall, revealing a crumbly sub-surface. This is bad news for wallpaper that might be hung on top of this.

Other spots. What happens is, this is a 90 year old house. Over the years, many coats of paint and other surface treatments have been applied to the walls of this dining room. These coatings are not necessarily compatible with each other. Plus they may have been applied without the proper surface preparation. Oil based paint, then latex, then someone rolls on a gloss paint, the next guy follows with latex but neglects to de-gloss the previous layer so the new layer doesn’t really stick well.

Somewhere along the line, something got chalky. Here you see I have wiped crumbly chalky substance from inside the wall. This is why the latex paint is not adhering well and pulled away so easily. Nothing sticks to dust or grit or chalk.

Gardz is cool stuff. It’s a penetrating sealer that soaks in and actually binds crumbly materials together, drying into a hard, solid mass. The problem here is, it won’t penetrate the paint that is on top of the unstable layer, so we’re still dealing with a wall that has potential to come apart (delaminate).

Gardz applied. You can see how it has soaked into the porous areas, but is sitting on top of the latex paint.

The problem with an unstable wall and wallpaper, is that, as wallpaper sits on a wall and the paste dries, the paper shrinks just a tad, and this shrinking puts tension / torque on the wall beneath it. Sometimes this is actually powerful enough to pull the layers inside the wall apart, resulting in seams that split open.

These are not “loose seams,” but the paper actually taking layers of paint and dust along with it. Really can’t be repaired.

So best to find a way to prevent it from happening in the first place. More on that later.