Posts Tagged ‘latex’

Tape Test for Unstable Walls

September 21, 2022

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!

Wall Prep Ahead of Wall Re-Do

July 20, 2022
This wallpaper in a Houston Heights townhome’s breakfast area was hung by “the contractor’s guy ” and he ran into some problems. First, I suspect the wall had not been adequately coated with a primer designed for use under wallpaper . This may be a large part of why the paper has come loose from the wall in places, and shrunk and gaps at the seams.
The wallpaper is an old-fashioned British pulp material , which is quite different from the non-woven material that this company usually prints on. If the installer was not familiar with hanging a pulp, yes, he can have a tough time of it.
There are other issues that the homeowner is unhappy with, such as tears, slices, patches, and, of course, these un-stuck seams. I’ve posted more pics previously, if you can Search to find them.
My task is to get the paper off and then prep the wall for hanging new material.
Most of the paper pulled off the wall easily. But there were areas where the guy had used a stronger adhesive to try to hold the edges down. Those would not come off the wall without causing damage to the wall. So I pulled off the top, inked layer and left the paper backing on the wall.
This stuff is porous and will bubble when coated with a water-borne primer , and with wallpaper wet with paste.
So I sealed these areas – I sealed the entire wall, in fact – with Gardz (by Zinsser ). This stuff is pretty incredible. It’s a thin, watery primer / sealer that soaks into the surface and binds loose components together, then dries hard and solid .
Latex paints and other water-based products (usually) won’t penetrate it, so won’t cause the underlying material to re-wet, expand , and bubble .
Just a note … due to pandemic and other supply chain related shortages , Gardz has become difficult to find. This can was about 1/4 full and I had it sitting behind my trash can, intending for weeks to toss it out. Now I’m glad that I procrastinated!
Once the Gardz sealer was dry, I skim-floated over it with joint compound , a.k.a. ” mud .” In most areas of the wall, my skim coat was as thin as possible, but I did have to make it much thicker over the areas with the paper backing stuck to the wall.
I set up three fans , and also used my heat gun , to get the smoothing compound to dry. I like the Plus 3 version made by the Sheetrock company. It sands easily and doesn’t make too much air-borne dust.
It took a couple of hours to dry. Then I sanded it smooth , vacuumed up the dust with my Shop Vac , used a damp sponge to get residual dust off the wall , and then let the wall dry once again.
Finally I applied a coat of my favorite wallpaper primer, Pro 977 Ultra Prime by Roman. I used a paint roller to roll it on to the main areas, and an angled trim brush to cut in around the ceiling and moldings.
Here is the wall all smoothed and primed .
Originally I had planned to strip , prep , and hang this half-wall all in one day. But ended up the prep took more time than I anticipated (about 8 hours ) , so we’ll let the primer dry overnight and save the wallpaper installation for another day.
The wallpaper pattern is called Strawberry Thief and is by the famous William Morris designer from the very early 1900’s . I’m sure seeing a surge in interest in his patterns, particularly this one. Do a Search to see other jobs I’ve done with it.

Wallpaper Paste Residue = Crackled Ceiling Paint

July 13, 2022

You’re looking at the junction between a wallpaper border at the top of a wall and the ceiling. You can see crackled and flaking paint on the ceiling.

This was almost surely caused by the previous wallpaper installer getting paste on the ceiling (which is typical and normal) but failing to wipe it off completely.

The paste is clear and difficult to see. Even when you do a diligent job, it’s easy to leave some residue behind.

The problem is that wallpaper paste attacks water-based paint, and will cause it to do what you see above … crackle, flake, chip off. This can happen if the paint was in place before the wallpaper paste got on it, or if there was paste residue and fresh paint was applied on top of it.

In fact, the decorative paint finish called “crackle finish” is accomplished by applying hide glue onto a surface and then coating it with latex paint.

The crackly paint on the ceiling is unattractive, and impedes adhesion. It takes a lot of scraping and sealing and skimming the wall to rectify this.

A way to avoid this is to astutely wipe off all paste residue. Better yet, what I do is to use special plastic tape at the top of my wallpaper strips, so that no paste gets onto the ceiling in the first place. Do a Search here to see previous posts describing that technique.

You can also use a stain blocker like KILZ Original oil-based primer, or BIN shellac-based primer, to seal off the area before painting. There are water-borne primers that claim to seal such problem areas – but I prefer to stick with oil or shellac.

Paint Peeling Off The Wall – A Bad Harbinger

March 16, 2022

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.

Wallpaper Coming Off – Delaminating Wall

January 14, 2022

An Unfortunate Situation

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.

Don’t Use Adhesive Picture Hangers

January 6, 2022
Yes, they’re strong enough to hold a 50lb painting.
But removing them may well take layer(s) of paint along with! Here you see a bubble that has lifted from the wall, as well as a break in the paint that was torn off by the adhesive picture hanger.
Several layers of paint have been pulled away from the wall. This is called ” delaminating .”
One reason for this is because the original underlying surface may have been dusty – as in dust from construction, or from sanding new drywall joint compound. Nothing sticks to dust. Other reasons for delaminating walls are incompatible surfaces, such as, an older home that starts out with oil-based paint, then someone comes along and applies latex paint over it without proper prep, then someone adds a gloss paint, then a ” flipper ” buys the house and slaps on a coat of paint without deglossing, ,,, on and on, situations that can cause layers of paint to not stick to each other. End result is that the wallpaper may come away from the wall, too.

Danger Signs of an Unstable Wall Surface

October 13, 2021
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.

Whoops! Someone Painted Over Old Wallpaper

April 21, 2021

Just looking at the walls, I had not noticed . But when I removed the light switch cover, it was clear that someone didn’t bother to remove the old wallpaper, and just painted over it.

Actually, they probably did do some prep, because you could not see seams under the paint. They must have taken steps to cover the seams.

And there was no flashing … difference in texture between paint over wallpaper, for instance, and paint over smoothing compound that was used to disguise those seams.

And there were no bubbles (caused by latex paint on top of wallpaper that absorbs moisture from the paint and swells) and only a few tiny loose areas.

Still, it would have been better if the previous guy had put some effort into removing the wallpaper, and then washing the paste off the wall and then sealing with a stain blocker, to prevent paste residue from causing the new paint to crackle and flake off the wall. Then the room would be adequately ready for paint.

Paint Problem

May 30, 2020


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.

Marker Bleeds Through Wallpaper – Prevention

February 19, 2020


Whoops! Whoever hung the mirror used an ink marker to indicate where the hooks would go. Ink bleeds through wallpaper – and paint and other substances, too.

I had not seen the stains on the painted wall before I started to smooth the walls. But, as you can see, in just a few hours, it worked its way through my rough skim-float, then after this was sanded and primed, the ink bled through again.

KILZ Original oil-based primer / sealer / stain blocker is my solution for this. I don’t trust any latex or water-borne products.

No “after” picture, but I daubed a fingertip full of KILZ on top of each green spot, and am confident that the stain will not come through the new wallpaper.