Top photo … my razor knife is pointing at pin point-sized specks on this wall. I found similar in multiple spots around the room. What’s interesting is that I have seen these exact same size, color, and configuration of specks on at least one other job.
What’s scary is that I fear these are made of something that will stain the wallpaper. There are lots of substances that can bleed through – through paint, through primer, and through the wallpaper and appear on the surface.
These could have been splashed onto the wall. But my feeling, especially since I have seen it in other homes, is that they are coming from within the wall surface. Maybe something contaminated the painter’s materials, or something inside the drywall.
There are stain blockers that can be used to seal these dots. My favorite is shown in the second photo. Oil or shellac-based work best. The problem is, wallpaper paste won’t stick to them. If just daubing onto a teeny dot, I wouldn’t worry about it. But when a larger area needs to be treated, you have to let that dry, and then follow up with a wallpaper primer.
Actually, depending on the stain, I don’t always trust the blockers. For these very tiny specks, I used my razor blade to dig into the wall and actually remove the affected area. The resulting holes were small enough that I didn’t worry about dents showing under the wallpaper.
In some instances, I did go back and cover them with KILZ.
There can be reasons for unstable walls, mostly cheap or poor quality paint, dust, someone applied paint over dust, improper prep, incompatible layers inside the wall built up over years (oil based paint, latex paint, dust, gloss paint, joint compound, etc.).
These can cause problems with wallpaper, mostly with the layers delaminating (coming apart), which causes the wallpaper seams to come away from the wall. Sometimes sheets of wallpaper simply fall off the wall.
This isn’t so much a problem with paint, because it just sits on the surface. But wallpaper shrinks when the paste dries, or expands and contracts with humidity, and can put tension on the seams
Before wallpaper goes up, one way to test for such unstable surfaces is the tape test . Use a razor blade to cut an “X” into the wall, scoring through the paint and maybe into a few layers beneath. Place a strip of blue painters tape over the cut. Pull the tape off the wall.
If paint comes away from the wall along with the tape, or if layers inside the wall come apart, you know you have to do a lot of specialized prep to stabilize the wall before hanging / installing the wallpaper.
This example is an interesting twist. The homeowner used a piece of tape to hold up a wallpaper sample. Then used an ink pen to write notes on it. When removed, the tape took the paint off – in the shape of the writing!
This Brooklyn Toile wallpaper by Flavor Paper on an accent wall in a nursery went up beautifully. The contractor had added new Sheetrock to one wall, and painted the other, old/original wall. I skim-floated both walls and sanded smooth, primed, and hung the wallpaper. Perfect! (Search here to see my original post.) But within less than a month, the homeowner contacted me and said that the wallpaper was ” coming off the wall .” It was a 1920’s bungalow in the Woodland Heights neighborhood of Houston. And therein lies the brunt of the problem. The wallpaper itself is not ” coming off the wall .” What’s happening is that the wall surface itself is coming apart – or, delaminating . This is because multiple layers of paint and other substances on the wall may not be compatible. A probably scenario: In 1920 oil-based paint was used. Later someone rolled on a coat of latex paint. Then the homeowners redecorated and used gloss paint. Then some ” flippers ” who had watched too much HGTV slapped on more paint without bothering to de-gloss or prime first. And somewhere in the mix you’ve got cheap paint and dust and other incompatible materials.Over time, and especially when stress is put on the wall surface, such as when wet wallpaper paste dries and the paper shrinks, this stress can tug at the wall and actually pull these layers apart. There are other contributing factors, too, such as humidity, temperature, and location. I find it interesting that the worst parts of the affected seams were toward the top of the wall. This speaks of heat, humidity, and forced air (either hot or cold) coming out of the air vent just to the right of this wall. This photo is of the area over a door, very close to the air vent. See how thick that is? It’s not just the wallpaper. There are several layers of wall coming apart. Some layers are clinging to the back of the wallpaper, and some are staying stuck to the wall. Multiple layers, many years of coatings on this wall. Easy to see the many layers. The paper itself, my blue primer, my layer of smoothing compound, paint, more paint coming off the wall. Then multiple layers of paint and texture still clinging to the wall. This shot is just below the ceiling.Same thing happening at the baseboard at the floor. Layers of paint separating from the wall in chunks. Some pulled off easily, and some I had to chop off with my 3″ putty knife.Most of the paint and unstable surface material clung to the back of the wallpaper. This pile is just three strips – only half the wall. But it’s thick and stiff and heavy because of the paint stuck to the back of the wallpaper. There was so much and it was so heavy and bulky that I had to carry it out to my van in two trips. When I got home, it totally filled my trash bin. Here’s the wall once all the other layers came off. Brushing my hand over it revealed a layer of dust. No wonder the paint and other coatings wouldn’t stick. Nothing sticks to dust. It’s like flouring a cake pan… The paint or wallpaper will kinda stick – but won’t really stick. Paint on top may be fine. But add a little stress from drying / shrinking wallpaper, and you may end up with layers that pull apart. Wiping the walls with a damp sponge removed a lot more dust. But the wall still felt chalky. Whatever type of paint this was, it was not holding together. I had to stabilize this chalky surface. Enter Gardz, a wonderful product – Gardz is a thin, penetrating sealer that soaks into porous surfaces and binds substances together. It dries hard and creates an intact surface. The darker area in the picture is where I’ve rolled on a test area. Gardz is thin like water, and it runs and drips and splatters. It’s imperative that you cover floors, countertops, and baseboards, and roll carefully, and roll upward rather than downward, to minimize runs and drips. A microfiber roller holds the liquid well, and reduces drips. Gardz is made by Zinsser. No photo of the finished wall, but I was very pleased with the stability of the surface. No more chalk or dust. Now, there still could be unstable or incompatible layers deeper inside the wall. (Latex paint over oil without proper prep.) But for now I feel pretty confident that this wall is solid and will hold up to the next process in preparation for getting the new wallpaper up.
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.
Before. Original chalkboard paint sealed off with KILZ Original to block any oil residue from chalk that might bleed through the wallpaper. Then primed with Roman 977 Ultra Prime wallpaper primer. Finished. Airy, floral, fun place to work!First strip goes up, lined up against the red light of my laser level. I measured and plotted the placement so that the center of that dominant black flower would drop along the vertical center line of the wall (about 8″ to the right of the laser line). Detail. I like the shadows in the background. Close-up shows pen & ink, and water color look of this design. Manufacturer is York, one of my preferred brands. http://www.yorkwall.com
Working from home these days, the homeowner wanted an office that was bright and encouraged creativity. The black chalkboard paint scrawled with slogans and proverbs had to go!
Almost exactly a month ago, I prepped the walls and started to hang the paper – only to discover printing and trimming defects. See my post from May 26, 2021. The on-line vendor, Burke Decor, was quick to ship out replacement paper from a different run. The new paper was fine.
The new light sconce plays off the black and gold colors in the wallpaper.
This refreshing yet peaceful abstract floral pattern sets the perfect tone, when your office is in your home.
The home is in the Heights neighborhood of Houston.
Look to the right of the can. Notice the tiny spots of red. This is rust, and rust is bad because it (along with certain other substances, like ink, tar, oil, tobacco, water stains, wood sap (knots), mold, mildew) will bleed through wallpaper. Maybe not immediately, but, over time, it will work its way through the primer and the paper and to the surface, leaving a spot that cannot be washed off.
Actually, there was a whole lot of rust along the entire height of this wall’s corner. An air conditioning leak had kept the drywall wet for a period of time, and rust had formed along much of the metal corner – called a “bead.”
I skim-floated over the affected area with joint compound, and that buried the rust … for a while. But rust (and other substances), will eventually work their way to the surface, leaving spots on the wallpaper.
So a stain blocker was called for, which will prevent any stains from bleeding through. For this I love KILZ – but only the “Original” oil-based version. The water-borne products just don’t measure up
Some reasons I skim-floated over the area was to provide a buffer space between the rust and the sealer in hopes that the rust would not make it all the way up to the surface, to create more material over the very corner itself that could soak up the sealer, and because the stain blocker would soak into the porous smoothing compound more so than to the sharp corner of the metal bead.
The owner of this newish home in the Woodland Heights (Houston) had her handyman remove the powder room mirror and its surrounding built-in wooden frame. Mirrors are often adhered to the wall with mastic, a tar-like substance. When the mirror comes off, some of the tar residue invariably remains.
In the top photo, you can see where removing the mirror took the blobs of mastic along with it, as well as round sections of the drywall. But there are small smudges of tar still remaining on the wall.
The problem is that tar (among a lot of other substances) will bleed through wallpaper (as well as paint, and a lot of other materials).
There are stain blockers like my beloved KILZ Original Oil Based, BIN shellac based, or others, that are designed to block these stains. But I don’t trust them. For water, rust, blood, wood sap, etc., yes. But for oil-based substances like tar, I want more assurance. The best way to prevent bleed-through is not to cover the stain, but to remove it.
So I take a Stanley knife and cut into the drywall and then peel up the top layer of drywall, taking along the offending tar residue.
So now the dangerous tar is gone. But you’re left with torn drywall. This is bad for several reasons. For one thing, you have an uneven surface that will look bad under the new wallpaper (or paint). And since the top, protective layer of drywall is gone, any moisture (such as from wallpaper paste or from latex paint) will penetrate into the torn paper layer – which will swell and cause bubbling.
All of which looks pretty bad under wallpaper or paint.
So I used the product Gardz to seal the torn drywall. It is formulated to soak into the paper; then it dries hard and acts as a sealer and moisture-blocker. It won’t block stains, but it will prevent moisture from penetrating the paper and causing bubbling.
Once that was dry, I skim-floated over the entire area with joint compound. It looks rough in the photo, but once it’s dry, I’ll sand it smooth. Then I’ll give it another coat of the penetrating sealer Gardz. See last photo. Once that is dry, I’ll cover it with a coat of Roman’s Ultra Prime Pro 977 wallpaper primer, when I prime the other walls in this powder room.
All of these various products do take a while to dry, especially the joint compound as thick as I applied it. So I went to this job site a few days before the install date, to do the initial prep, so it would have plenty of time to dry before I come back for the final prep and wallpaper hang.
Hard to see, but the paint on this wall is crackling. This is most likely because there are unstable and incompatible layers of paint underneath.
In an old house like this (1940’s), there will have been many treatments to the walls over the years. Original oil-based paint, covered by latex paint, gloss paint, dust, more colors and layers of paint. And virtually never does the workman prep the walls properly.
Latex doesn’t like to stick to oil, and most paints don’t like to stick to gloss, plus other factors. So what happens is that all these disparate layers rebel, and sometimes you end up with flaking or peeling.
If wallpaper is applied on top of these unstable walls, when it dries and pulls taught and puts tension on the wall surface, there is the potential for these layers to give way, and you can end up with a curled seam, under which are layers of delaminated wall.
I have just finished stripping off wallpaper that I hung 12 years ago. The walls beneath are in perfect condition.
Except that, along just about the full height of just about every seam, I discovered these hairline cracks.
What is very odd is that the cracks have not made the wall unstable, and no material has pulled away from the wall (as often happens when you have layers of incompatible materials that will not adhere to each other – do a Search here on “delaminating”).
I believe that my original prep 12 years ago was to skim-float the walls and sand smooth. Then I wiped off the dust with a damp sponge, then followed with my favorite primer at the time, KILZ Original oil-based primer.
My thought is that the KILZ, or possibly the underlying joint compound, has separated due to tension put on it by the wallpaper seams, possibly shrinking and expanding over the years due to minute fluctuations in humidity and temperature.
Why that happened I don’t know.
This past year, I’ve had opportunity to remove wallpaper from several jobs that I hung as far back as 20+ years ago. All were over the very same original prep conditions. But none showed these little hairline cracks.
I always like to understand why something happens. That way, you have the potential to prevent it from happening in the future.
Not that I’m particularly concerned in this case. The tiny cracks have not created any problems, and the wall is not unstable.
I felt perfectly comfortable hanging the new paper right on these walls – however, I made very sure that no seams of the new paper landed exactly on top of those cracks. That would eliminate the chance of any stress put on the cracks by the new seams potentially causing them to weaken and pull away from the wall.
See the green vertical line to the right of the paint can? The previous wallpaper installer probably had a little white wall showing at a seam, so used ink that matched the color of the wallpaper to disguise it.
Ink (along with other substances, like blood, rust, water stains, oil, tobacco, mildew, wood sap, and others) can bleed through joint compound, paint, and wallpaper. Sometimes it takes a few months or years.
So it’s important to discover these stains, and to treat them with a stain-blocking sealer. Water-borne products simply don’t work, no matter what the label claims. Shellac-based sealers like BIN are good. But I like KILZ Original, the oil-based version.
The Wallpaper Lady's Blog 