Crumbly / Unstable Wall Issues

Starting to strip wallpaper. You see the top, inked layer, the tan backing layer, and the white skim-floated wall beneath.

Wall surfaces delaminating at seams

Gardz, a penetrating sealer that binds surfaces together and dries hard.

My first idea was to just Gardz the lifted areas. The sealer is newly applied and still wet in this photo.

Gardz’ing the whole wall created a more stable surface. This doesn’t look much different from the photo above. But in actuality, the the Gardz has sealed and “locked down” the surface, as well as soaked into the material and sealed the inner layers as well.

Applying a skim-coat to even out the surface levels.

Once this skim-coat is dry, it will be sanded smooth.

The installer of the original paper did a good job of skim-floating the wall and creating a smooth surface. But he didn’t apply a sealer or primer. Thus, when I used water to strip off the old wallpaper, the moisture soaked into his skim-coat (drywall joint compound, a plaster-like substance, which we also refer to as “mud”). Some of the skim-coat came away from the wall,,, particularly in areas of stress, such as where the wallpaper seams had lain.

In fact, long (years) before I began stripping the wallpaper, many of the seams had started to pull away from the wall, taking inner layers of the wall along with them. This is because wallpaper shrinks as it dries, and that creates tension on the wall. If the wall surface is unstable, these layers can delaminate (come apart), and the result is an open seam with chunks of wall material stuck to it.

This can also happen over time, as temperature and humidity changes can cause the wallpaper and / or wall surface to absorb and then let go of moisture. All this puts stress on those wallpaper seams and on the layers inside the wall.

Besides these seam areas that let go, I had one wall where the entire surface came apart in a mottled effect.

Another factor is that the original skim-coat had been applied over a glossy paint. It’s hard for anything to stick to gloss. The guy probably should have rolled on a “bonding primer” before applying his skim-coat.

Of course, all that increases the time and materials needed, and ups the cost to the homeowner.

Gardz is a wonderful product that is designed to soak into surfaces and “bind them together.” It dries hard and is pretty water-resistant. It was originally intended to “lock down” torn drywall. But workmen quickly discovered that it would fix a whole lot of other surfaces – such as my delaminating skim-coated walls.

At first I thought I would just Gardz (we use it as a noun and as a verb!) the areas that were lifting. Once it dried, I intended to skim-float over these areas, sand smooth, and then prime the entire room with my usual wallpaper primer – Roman Pro 977 Ultra Prime.

But I realized that, even after I wiped down the walls with a damp sponge, they were still covered with powder or grit. This was powder from the layer of skim-coat, as well as residue from wallpaper paste. Neither my primer not wallpaper will stick securely to powder.

So I decided to roll Gardz on to all the walls, ceiling to floor.

Fifth photo – I was really pleased with the way the Gardz soaked in and drew all those layers together. There was no more power on the surface, and the inner layers of the walls were all pulled together.

To even over these vacant areas, and to create a pristine new surface, I skim-floated over the entire wall surface – all walls, floor to ceiling. See last photo.

Once that is dry, tomorrow morning, I will sand everything smooth. Next I’ll apply my 977 primer.

Then walls will be stable, and the surface will be ready to take on the new wallpaper.