Fixing Drywall Damage From Where Vanity Was Removed

The powder room in this 1990’s home in the Houston Heights is being updated, and that means replacing the wall-to-wall vanity. Here the vanity has been ripped out. The areas where the backsplash was adhered to the wall have pulled the top surface of the drywall off. In addition, the plumber had to cut out a section of drywall in order to gain access to the pipes, so he can install the new faucet and handles. You can see the connections roughed in.

You can’t hang wallpaper over this mess. First of all, it way too uneven – all those bumps will show under the new wallpaper. And the outline of the ” trapdoor ” will leave a big square ridge under the paper. Thankfully, the plumber secured the panel with drywall screws – most plumbers just leave you with a chunk of drywall floating in space, or even just an empty hole.
Back to patching issues … in addition, the torn areas of drywall will absorb moisture from the wallpaper primer and / or paste and expand, creating bubbles that will show under the new paper.
I needed to fill in dips and gouges, even out high areas, and prevent bubbling drywall.

Gardz by Zinsser to the rescue! This is a penetrating sealer that soaks into porous surfaces and then dries hard, binding them together and creating a stable surface, as well as resisting moisture from water-based top coatings.

This picture doesn’t look much different, but here the torn drywall is a little darker, indicating that the Gardz has soaked in and dried. The surface is now ready for a skim-coat.
But first, the trap door needs to be addressed. I covered the cut areas with four strips of self-adhesive mesh drywall tape (no photo).
Then I went over everything (wall to wall) with joint compound (commonly referred to as mud ) (no photo).
Because of the thickness of the high and low areas, this had to be a thick coat of smoothing compound, and would take a long time to dry. So I went to the jobsite two days ahead of our install date, to do these initial repairs.
And – no – you can’t use quick set or hot mud or 5 or 20 minute mud to do these repairs. These products are intended for repairs of small areas. Top coatings like primers, paint, and wallpaper paste do not stick well to them. Don’t let a contractor sweet-talk you into letting him use any of these to smooth a large area of wall.

Here is the wall after my first, heavy, coat of smoothing compound. I use Sheetrock brand’s Plus 3.

The bubbles you see just left of center show that Gardz didn’t 100% do its job of sealing out moisture, as a little expansion and blistering has occurred. Not a biggie. These will disappear when the surface is sanded. There is usually not a problem with these re-appearing.

When I got to work two days later, the smoothing compound had dried. I sanded pretty smooth. Then vacuumed up the dust on the floor, and then used a damp sponge to wipe residual dust off the wall. This is important, because no coating will stick to dust.
The wall still wasn’t perfectly smooth, so I did another skim-coat. This was much thinner, so didn’t need a lot of time to dry. I used a fan and my heat gun to speed things along.
Once that was dry, I sanded it smooth, vacuumed and then wiped off all dust. Then rolled on my favorite wallpaper primer Roman Pro 977 Ultra Prime. I have the paint store (Murphy Brothers in central Houston) add a little blue tint, so I can see it when I apply it to the wall.
What a transformation! Now this wall is ready for wallpaper!

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.