Posts Tagged ‘off-gassing’

Strange Bubbles in Drying Wallpaper

September 21, 2021
Air bubbles appearing as this wallpaper dries.
Smoothing brush, and plastic smoother.

It’s not uncommon for vinyl wallcoverings to develop bubbles as the paste dries. This is called “off gassing” and it happens because the vinyl is impenetrable and there is nowhere for air to escape.

But these days, most paper products – such as this one – allow air to pass through, and dry nice and flat with no bubbles or blisters.

One thing to keep in mind is, virtually always, these bubbles will disappear as moisture evaporates and the the paper and paste dry and shrink taught. So the less fiddling you do with it, the better. (And exception would be large bubbles, which should be addressed.)

One way to treat bubbles is to chase them out toward a seam, using a tool such as the plastic smoother. You can also use a pin or razor blade to poke a tiny hole in the paper to let the air escape. It helps to do this in a part of the pattern, and not in an unprinted area, to disguise the hole.

I also like to understand why something like this happens. If you know what caused it, you have a chance of preventing it the next time.

I primed the wall with my usual primer, so I don’t think there would be issues with moisture being trapped between the primer and the wallpaper. But then again, you never know what is inside the wall – many walls have been painted multiple times, and some layers may not be compatible.

Another cause could be the plastic scraper. The bristled smoothing brush uses a more gentle action to push the paper into place. The scraper could actually overwork and stretch the paper. In fact, if you use the scraper to try to push bubbles out to a seam, you end up creating more bubbles.

I use the plastic smoother mostly for seams, and not so much for smoothing a full strip into place. But it’s possible that I used it more than usual this time, and stretched the paper, creating conditions for the bubbles to form. In fact, on one strip, I gently pulled the bottom portion away from the wall and then put it back in place, but making sure to use only the bristle brush. This did eliminate the bubbles.

But, again, if you just wait it out until the paper becomes thoroughly dry, nine times out of ten, all the bubbles will be gone by morning.

Weird Bubbles Develop on Wall

January 21, 2021

This wall had a slight texture that needed to be skim-floated and then sanded smooth. After I applied the smoothing compound (drywall joint compound), a half hour or so later, these tiny blister bubbles appeared. This is off-gassing. But from what is a mystery.

The only clue is that this area is around where the hand towel was positioned next to the sink. So this area would have received a lot of splashing of water and also soap and other toiletries.

My guess is that some of these substances stuck to the wall. And for whatever reason, when they were covered by the joint compound, they released air / gas, which caused these bubbles.

I’ve seen this before. But this time, some of the bubbles were large enough that they did not sand down smooth and even with the wall surface. So I had to do a light touch-up skim-coat on top.

Once I got the wall smoothed, I wasn’t too concerned. I don’t believe that anything causing these tiny blisters would be something that would bleed through and stain the wallpaper.

Some substances do stain wallpaper, though. For more on that, do a Search here.

Peel & Stick = Piece of Sh!t

September 24, 2019


We’re seeing more and more of this peel-and-stick, supposedly “removable” and “repositionable” plastic wallcovering. Unfortunately, many homeowners read the lofty claims by the manufacturers and think it will be a perfect alternative to traditional wallpaper. It is not.

The stuff is awful – I won’t hang it, and most of my friends won’t either.

First of all, you don’t NEED an alternative to traditional wallpaper – you just need quality paper and someone who will properly prep the walls and then properly install the paper.

Getting back to P&S, the stuff is virtually impossible to hang. Imagine a 9’x2′ strip of Contact Paper, trying to position that on a wall without it wrinkling or sticking to itself, and then trying to butt another strip up next to it. Not gonna happen. It also does not “remove easily” … well, it does, but it will tear your wall apart in the process.

These homeowners had some guys doing other work in the nursery, and they said they could hang the wallpaper, too. They weren’t experienced paperhangers, and they weren’t up to the battle against this P&S. Virtually no one is.

First, they should have smoothed out the textured wall. Second, most P&S products spec that the wall should be sealed with a semi-gloss paint, which needs to dry and cure for two weeks. As you can see, this adds time and labor charges to the job.

I’m not sure why there are gaps at the seams (top two photos), but better prep would surely have helped prevent this. The large wrinkles are due to the inflexiblity of the material and its unwillingness to twist or stretch into position. With the baby on the way, the homeowner dad got desperate and used nails to try to tack down the curling paper.

The baby girl arrived, the parents lived with this wall for a while, and, when life settled down, they contacted me. I counseled them to forget the P&S and to choose a traditional wallpaper.

They zoomed in on this butterfly pattern by SuperFresco. This material is one of the newish non-woven materials, which contain a component of fiberglass and thus don’t expand or shrink, and won’t tug at the wall, so fewer worries of seems popping loose. These qualities also make it possible to dry-hang the paper, by pasting the wall instead of pasting the paper. I usually paste the paper, but on a single accent wall such as this (no toilets or sinks or fancy moldings to work around), pasting the wall works beautifully. It also saved me lugging my heavy, bulky work table up to this townhome’s third floor. 🙂

Removing the P&S paper was easy – it is strong and held together while I tugged it off the wall … I could do it all from the floor, without even climbing the ladder. Unfortunately, it took much of the paint along with it. So much for the “removable” claim.

It was still as sticky as the day it was born – so I rolled it all up and stuck it to itself and tossed the whole mess into the trash. Done and gone!

I skim-floated the wall to smooth it, sanded smooth, vacuumed, wiped residual dust off the wall with a damp sponge, and then rolled on Gardz, a penetrating primer-sealer, that also is a great undercoat for wallpaper.

All that (especially waiting for the smoothing compound to dry) took several hours. I think it was about 6:00 before I started hanging wallpaper!

Thin non-wovens generally go up with pleasingly invisible seams, and this one did, too. I was surprised to discover more than a few large wrinkles and bubbles. This could have been because the paper got twisted during installation, because the wall was smooth but not flat, because of some uneven reaction between the substrate and the paste which caused off-gassing (burps!), or some other reason. But it meant that I had to go over the wall several times, checking to be sure all areas were firmly secured to the wall.

The finished accent wall looks great! It’s a gentler pattern and a quieter color, and doesn’t hit you in the face as the original floral pattern did. There’s a little bit of fun shimmer in the scattered pearlized butterflies, and the blue-grey wings coordinate nicely with the three grey walls in the rest of the room.

Finally, Baby Girl is ready to move into her own room!

Soft Mattress Ticking Stripe in an All-White Bathroom

April 24, 2019


With just paint on the upper walls, this all-white bathroom was simply … too white. The addition of a soft stripe, in the shape of a classic mattress ticking pattern, was just enough to add some warmth and definition to the space.

While I like the pattern, I am not fond of the material, nor the brand. Norwall is one of the lowest-priced manufacturers out there, and … you get what you pay for. This is a solid vinyl wallpaper with a paper backing. The vinyl surface sounds attractive to homeowners, because it is a tad more stain resistant than other papers, and because it repels water.

The bad news is that humidity (such as when someone takes a shower, or splashes water on a seam) tends to find its way behind the seams and into the paper backing. That paper then swells and pushes away from the wall, causing the seams to curl.

Over time, the vinyl top layer can actually separate (delaminate) from the paper backing, leaving curled seams that cannot be reattached.

In addition, the seams are always a little “pouched” when the paper is installed, and never lie completely flat. It’s also common for this material to bubble or blister as it dries … I call it “burping” … or more properly termed off-gassing as the air released by the drying paste tries to find an escape but is trapped by the vinyl surface. So you have to keep going around the room chasing out bubbles. Really small ones usually disappear as paper dries.

Type in key words and use the Search feature here (upper right corner) to read my previous posts about these topics.

This was the first time I’ve encountered a Norwall solid vinyl paper-backed product that was not pre-pasted. Maybe the manufacturer has figured out what made it’s wallpaper so crap…py… er… disappointing. To be honest, the paper I worked with today (which had to have adhesive applied by hand/paint roller) went up with fewer problems than usual. There were still blisters, and still seams that were not as flat as they should have been. But overall, it was better than I expected. This is not the same as being “satisfactory.”

Only time will tell how this product stands up to humidity in a family bathroom.

This is a new-but-classic-looking home in the Woodland Heights neighborhood of Houston. The interior designer is Stacie Cokinos of Cokinos Design.

UPDATE: This paper had only been up for a few months when the homeowner called me to say that some of the seams were curling. As expected, this was due to humidity / moisture…. either splashing water or the housekeeper’s damp rag running along the top of the chair rail. Or possibly humidity from showering.

Either way, some of the seams were starting to curl away from the wall, and were on their way to delaminating. I was able to tack down the curls. But if the paper starts to delaminate (vinyl layer separates from paper backing), there is no cure for that – at least, not anything that looks good.

My Solution for Yesterday’s Cantankerous Wallpaper

June 27, 2018


Here’s what I ended up doing with the Norwall pre-pasted, paper-backed, solid vinyl wallpaper that was featured in my previous post. This brand is known for curling seams, as well as seams that just don’t lie down nice and flat, but appear to be “pouched” just a tad. I experimented with several pasting techniques, hoping to get nice, flat seams.

… It didn’t do well when I pasted it with full strength paste, as it got gummy and dried out too quickly. And it didn’t do well when I pasted it with diluted paste. Nor was it happy when I ran it through a water tray as per mfgr’s instructions (and then rolled a thin layer of paste onto the wall); it went up great and looked good … but look back at it after 10 minutes and discover that it has bubbled. What worked best was to wet it in the water tray and then unbook the strips and let them hang to dry out for 10-15 minutes or more. This left enough moisture for the paper to grab ahold of the paste I had rolled onto the wall, but eliminated the excess moisture that was causing the off-gassing and bubbles.

I wet a bunch of strips at a time… I had them hanging over the shower rod, on the towel bars, over the door, and the small ones got set on the toilet to dry.

Traditional to Traditional – Bold to Subdued

March 31, 2016

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The colorful botanical / bird original wallpaper is a classic design and color, but the homeowners had grown tired of it. Plus, as you see in the second photo, some of the seams had begun to curl. This is common with paper-backed solid vinyl wallpapers, especially in humid rooms (like bathrooms) or rooms with no air vents (this bath had neither A/C vents nor an exhaust fan) and the big reason why I try to steer clients away from this material.

The next photos show the new wallpaper. Originally, the homeowner wanted a woven faux grasscloth, which she saw that I had installed in a friend’s bathroom. But she could not find a color that worked with the color of the tile in this Tanglewood area 1950’s ranch style home’s bathroom. This damask pattern turned out to coordinate perfectly! It also cloaks the walls in a little pattern, without being busy (because it contains only two soft colors), and adds more interest to the room than the faux grasscloth would have.

This wallpaper pattern is by Thibaut Designs, and was bought at a discounted price from Dorota Hartwig at Southwestern Paint on Bissonnet near Kirby. (713) 520-6262 or dorotasouthwestern@hotmail.com. Discuss your project and make an appointment before heading over to see her.

This product was a paper-backed solid vinyl (read my comments above). It was thick and stiff and difficult to work with. The seams showed more than they should have, and there were edges of the paper that were warped by the plastic wrapper that never relaxed completely once the strip was pasted and applied to the wall, leaving slight waves at some seams. The material did not turn corners well, and I was never happy with any of the outside corners. There was also off-gassing, which is when a strip goes up and looks wonderful, but as it dries, moisture is trapped between the wall and the vinyl and has nowhere to go, so bubbles form under the paper.

Note to Self: Don’t let any other clients buy this product.

Vinyl Papers and Bubbling

June 25, 2014

Digital ImageIf you look closely to the left of the mirror, you can see little air bubbles under the wallpaper. This is called “off-gassing” – I just call it “burps.” 🙂

This happens mostly with pre-pasted paper-backed solid-vinyl wallpapers, and is a result of the wet backing trying to dry, but the moisture being trapped between the wall and the vinyl. Usually, small bubbles like those in the photo disappear as the paper dries.

But sometimes, like with this paper, very large, even fist-sized air pockets will develop. So I always go back over the room a few times, chasing these bubbles out with my smoothing brush or squeegee.

I usually recommend against these paper-backed solid-vinyl papers, and this is one reason why. Another reason is that, in humid rooms such as bathrooms, the backing tends to absorb moisture, which leads to curling at the seams, something that cannot be reglued or repaired.

Wallpaper, Off-Gassing, and a Lesson in Science

June 17, 2014

IMG_2550Here is a textured and patterned heavy vinyl wallpaper on a non-woven backing that I put on the back of a set of bookshelves in the home of a young family in Bellaire. The interior designer was Pamela O’Brien, of Pamela Hope Designs.

I did have some problems with bubbles developing in the material, but I smoothed them out, and everything was fine when I finished. But … a couple of weeks later, the designer’s secretary called to let me know that more bubbles had developed. I went over to the home today, to do what I could do to get rid of the bubbles.

Bubbles like this are caused by “off-gassing,” which means that, as the paste dries and moisture evaporates, air gets trapped between the thick, impermeable vinyl wallcovering and the wall, which in this case was probably wood painted with an enamel or schellac based paint (as opposed to drywall coated with latex paint), with my primer on top of that. In other words, no where for the air to go. So all those air molecules gathered together and pushed up bubbles under the wallpaper.

The representative from the wallpaper company said this in his reply to me, “I think you are right. The surface you hung on looks like an enameled coated wood or particle board. In either case the surface could not absorb moisture, as regular wallboard would, so the moisture would have no where to go, being that the vinyl is impervious. Putting on wall liner might have given enough air space to circulate and dry. Bookcases are very hard to hang anything on because binding to a hard surface is always difficult and all the more with a commercial vinyl.
“The vinyl is now formulated so there is very little off-gassing, and what there is comes off the front.”

OK, it’s good to know they are aware of the problem, and have developed a solution – a paper that “breathes” so as to allow the air to escape from the surface, rather than the back. But that didn’t help me much, since I still had to deal with this older version of the product, which was off-gassing from the back, and bubbling!

I revisited the home today, almost a month after I originally hung the paper. A few bubbles were visible. (I suspect that some evaporated and flattened out during preceeding weeks.) I was surprised to see that there was still a lot of wet paste under the paper, yes, even four weeks after it hand been hung. With a solid wall surface behind it, and a solid vinyl surface on front, there was simply no where for the moisture to go.

I was very happy that, for almost all of the bubbles, all I needed to do was prick a tiny hole and then push the air out. Since the paste was still active, the vinyl quickly stuck to the wall behind it. There was only one area where I had to cut a small slit in the paper and work some adhesive behind.

When I left, it was all nice and flat, and it looked great.

I do love it when I can get a little science lesson along with my wallpaper projects!