More Work on Yesterday’s Delaminating Wall

Re yesterday’s post … after I got the wall stabilized, I skim-floated the surface to smooth it. That dried overnight, and today I sanded it smooth, vacuumed up the dust and then wiped residual dust off the wall with a damp sponge, and then primed with good old Gardz. I feel pretty confident that that wall is secure enough to withstand the tension of drying wallpaper. But, just to be sure, I applied a liner. A liner is a special paper that goes on the wall under the decorative wallpaper. In this case, the purpose is to distribute tension so that no stress is placed directly on the wall. So it’s important that the seams of the liner and the decorative wallpaper do not line up or fall on top of each other. This way any tension is dispersed and distributed, and any inner surface that wants to delaminate will be held in place by the layers of paper over it. In this photo, the section to the left has the new white liner, and I am moving toward the right to finish this wall.

t’s important that the liner be flat and that the seams lie down tightly, so no bumps or ridges show under the new wallpaper. I was really pleased with how these seams just melted away.

There are all kinds of liner papers out there. This one is a stiff, somewhat thin non-woven option made in Germany.
Using a liner does add to the cost of the installation, for both material and labor to hang it.

Paint Pulling Off Wall Where Tape Was Removed – Surface Stability Test

Paint pulling off wall where tape was removed.

Paint pulling off wall when painters tape was removed.

Paint pulled off wall and stuck to back of tape that was pulled off wall on new construction site.

It’s important to have a stable surface under wallpaper.

That’s because, when wallpaper gets wet with paste, absorbs moisture from the paste, and it expands. Then, as it dries, it lets go of the moisture and shrinks. When wallpaper dries and shrinks, it puts tension / torque on the walls.

If the surface under the wallpaper is not stable, the tension of the drying wallpaper can cause the underlying surface to pull away.

This photo is not showing the wallpaper pulling away from the wall. What is happening (usually) is that the paint (or whatever has been applied to the wall), has actually delaminated (come apart) from the wall.

This results in a “curled” seam, or a “popped” seam.

One way to test for this is to apply a strip of tape (blue painters tape, tan masking tape, clear Scotch tape, or other), let it sit a few minutes, and then yank it off. If the tape takes any paint along with it, you have a potential problem of the wallpaper not adhering correctly.

This is why it’s important to:

1, Before applying any coating, you must remove all dust from the wall, using a damp sponge, which must be rinsed frequently

2, Before hanging paper, a primer formulated specifically for wallpaper should be applied / rolled on and cut in to edges

A wallpaper-specific primer is designed to withstand the torque put on the wall as wallpaper dries. And it facilitates installation by allowing sufficient “slip” (maneuvering the paper) and “stick” (adhesion). The chemistry behind all this is fascinating – but too complicated to get into here.

If a wall is too “iffy,” and you don’t feel like the mess and expense of scraping off all the old paint, a liner can be applied before the actual wallpaper is hung.

A liner lessens the drying time of the wallpaper, which reduces the time there will be stress on the wall. A liner also redistributes stress on the wall, so much less chance of having seems detach from the wall.

A liner also adds additional cost to the job – for both material and labor, which may include an additional day(s).