Contractor Prepped Walls – But Left Dust

I usually insist on prepping the walls for wallpaper. But we had a time crunch here, and the homeowner asked her paint contractor to strip the old wallpaper and smooth the walls.
He did a good enough job of skim-floating and sanding the walls smooth.
Unfortunately, he neglected to wipe residual dust off the walls.
The problem is that nothing sticks to dust. Not paint, not primer, and not wallpaper. Over time, stress, humidity, and other factors can cause the wallpaper to expand and contract, which puts tension on the seams. This tension tugs at the seams , and if the wall surface underneath is unstable ( dusty ), the layers can pull apart ( delaminate ), and you end up with failing seams.

So I wiped down every square inch of wall, using a sponge and bucket of water. I rinsed the sponge frequently, to prevent build up of dust on the sponge.

Here’s drywall dust wiped off in just a few swipes. In the background, you can see tracks of my damp sponge along the wall. These damp areas will need to dry thoroughly before I can apply my wallpaper primer. A heat gun helps speed that process along.

One fear that I have is because, as you see in the photo, the contractor spray painted the woodwork, and in so doing, got a lot of overspray onto the wall. This can be painted over without much problem.
But, as mentioned above, putting wallpaper over this can open a can of worms.
Even with a good wallpaper primer underneath, the drying / shrinking wallpaper can put stress on the seams. If the wall underneath is dusty, the layers may let loose of one another and result in a popped seam .

Paint Peeling Off The Wall – A Bad Harbinger

Prior to prepping for wallpaper, I’ve removed a hanging shelf. It had stuck to the paint, and pulling the shelf off the wall also took some of the paint along with it.

This is a bad sign. If paint will release from the wall so easily, it’s an indicator of an unstable surface underneath, that the paint is not able to bond to.

That also bodes poorly for any coatings applied on top of it, such as my smoothing compound, primer, and wallpaper.

The most worrisome of these is wallpaper. Because unlike other substances, wallpaper expands when it gets wet with paste, and then as the paste dries, the paper shrinks a tad and puts stress / torque on the wall. If the underlying surface is unstable, these layers can actually pull apart, resulting in a ” popped ” seam.

This is not a ” loose ” seam and cannot be simply glued back together. It’s layers deep inside the wall coming apart / delaminating from each other, and virtually impossible to really repair.

So what causes this? Do a Search here to read my other posts on this topic. But causes can include incompatible surfaces, such as old oil-based paint covered with newer latex paint, gloss paint covered with new paint without proper prep / de-glossing, chalky or calcimine paint, or coatings applied to a dusty wall.

In all these cases, the top coatings won’t be able to adhere tightly, and can result in what you see here – the top layer(s) of paint pulling off the wall with just a little stress.

Even worse, in my world, is the potential of the surface beneath wallpaper seams coming away from the wall.

Fun Over-the-Door Kill Point With Swirled Damask

Often when hanging wallpaper, you start in a corner. As you work your way around the room and make your way back to that corner, and your final strip meets up with the first strip, this virtually always results in a pattern mis-match (not shown). That’s why we try to hide it behind a door or in another inconspicuous place. But sometimes, as in this powder room, there is no out-of-the-line-of-sight corner to put the “kill point,” as we call it. I think the room looks better when the pattern matches in all four corners (as in the photo).

So, instead of ending with an 8′ long pattern mis-match in a corner of this room, I decided to put it in a 1′ high area over the door – where not many people are going to be looking, anyway. Here is the gap where my last strip (on the right) will meet up with the first strip (on the left) .

Positioning the last strip in place.

Here I have overlapped the final strip on top of the first strip. Amazingly, the pattern looks like it matches. (The pattern doesn’t really match, but the design is so similar that no one is going to detect the difference.)

Once the strip on the left is overlapped onto the strip on the right, I’m ready to make a double cut – a fancy term for a splice. I cut through both layers of wallpaper – in this case squiggling a little to follow the contours of the design, rather than make a sharp straight cut. In the photo, I’m removing the cut-off piece from the top layer.

Here I have removed both cut-off pieces, from the top and bottom layers, and am getting ready to fit the two remaining strips together.

Strips smoothed together, pasted wiped off the surface, and this looks pretty darned good!

Here I’ve done a few touch-ups with pencil, to soften the look of the two very small motifs that got chopped off straight. A little more artistry with colored pencils, chalk, or paint would disguise these even more.

It’s important to note that you don’t want to make your splice directly on the wall. You don’t want to risk that your razor blade could score the wall surface. Because if the wall becomes un-intact, when the wallpaper dries and shrinks and puts torque / tension on the seam (and this doesn’t always happen right away … it can happen over time, with changes in temperature and humidity), it can cause the disturbed / cut portion of wall to delaminate and pull apart. This means that this weak point in the wall can come apart, resulting in a seam that pops open, taking interior layers of the wall with it. This is a lot harder to fix than a strip of wallpaper that simply comes loose from the wall. The best way to prevent this is to not cut into the wall in the first place. The best way to ensure that is to use something to protect the wall when you make your cut. Some people pad the wall with scrap wallpaper, or strips of old vinyl. But I much prefer these ingenious strips of polycarbonate plastic (pictured). They are thin and flexible, but hard enough that there is no way you could push a razor blade through them. They’re about 2.5″ wide, and come in rolls of … I forget how many feet are on a roll. If you are interested in getting your hands on some of this stuff, send me a Message, or email me at wallpaperlady@att.net