Posts Tagged ‘humidity’

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!

More William Morris Strawberry Thief in Houston Heights Hall Bathroom

June 24, 2022
Because I feared unstable walls in this 1920’s bungalow in this neighborhood (do a Search for previous posts), before hanging the decorative wallpaper, first I hung a non-woven liner paper on all the walls. That’s the white material you see in the photo.
The liner was hung horizontally so its seams can’t line up with the decorative paper. The idea is to disperse tension from drying wallpaper and changes due to humidity and etc., so as to deflect tension away from sketchy wall surfaces, and thus prevent delamination of multiple unstable layers deep inside the wall. Again, do a Search here to learn more.
Finished vanity area, with pattern centered on the light fixture.
Corner shot.
This colorful and symmetrical pattern is quite popular; I’ve hung it a number of times just this year.
Englishman William Morris designed wallpaper and fabrics during the late 1800’s and early 1900’s.
The styles then were Art Nouveau and Arts & Crafts. This design reflects a bit of each.
Wallpaper expands when it gets wet with paste, and then can shrink just a tad as it dries. The liner helps prevent that, but you can still end up with teeny gaps at some seams.
To prevent the white backing from showing through, I run a stripe of dark paint under where each seam will fall.
I use matt finish craft paint from the hobby store, diluted with a little water (in the orange bottle cap) and smeared on the wall with a scrap of sponge. Use a ruler or level and a pencil to mark where you want to stripe the dark paint.
Remember to allow for that expansion as the paper absorbs moisture from the paste. Meaning, if the paper is 20.5″ wide, and expands 1/2″, you’ll want to run your line at about 21.” And make sure that your painted swath is about an inch wide.
I also run a bit of dark chalk along the edges of each strip, to prevent the white substrate from showing at the seams (no photo).
Morris & Co. makes this iconic Strawberry Thief.
Interestingly enough, most times when I’ve hung a Morris paper, it’s been a non-woven paste-the-wall material.
Today’s option was a surprise – a traditional British pulp . This is a pretty basic and somewhat old-fashioned type of substrate . Sort of like construction paper, or the pages of an old family Bible .
The paper is very fragile , and can tear easily. You have to keep using new razor / trimming blades, because the material dulls blades quickly, and when dull they will drag and tear the paper.
Pulp papers also require a soaking / booking time after pasting , to allow time for the material to absorb the paste , soften a bit, and expand . The edges of the strips like to dry out , so I’ve learned to dip about 1/4″ of the booked ends ( booked means the pasted side of the wallpaper strip is folded onto itself, bottom edge folded up and top edge folded down to meet in the middle), into a bucket of clean water.
Then it goes into a black plastic trash bag to soak and relax for a few minutes before hanging. I use this opportunity to paste the next strip.
Non-woven wallpapers have advantages, because they do not expand when wet, and therefor you can get accurate measurements. They also can be pasted and hung immediately, with no waiting time. Alternately, you can paste the wall .

Wallpaper Woes in Chinese Restaurant

April 10, 2022
While waiting for my order to be ready, I couldn’t help but notice problems ….
Wallpaper starting to curl at the seams.
Wallpaper twisting in corners as the building shifts and drywall moves. This is pretty common in Houston.
Other signs of poorly maintained building and/or climate control issues.
Seam curling back. I believe this to be a lower-end solid vinyl wallpaper on a gritty paper backing – one of my least preferred types.
When the walls are not prepared correctly, and the paper is not hung properly, and when there is a lot of humidity (door left open, steam from kitchen getting into waiting area, A/C not running or turned off at night), humidity can enter into the seams and be wicked up by the paper backing. The paper expands and pushes away from the wall, causing the edges of the wallpaper to curl back.
The next step is that the vinyl surface can actually delaminate (come apart) from the paper backing. This is pretty impossible to repair.
At the very bottom, you can see the vinyl separating from the paper backing.
The wallpaper has been wrapped around this outside corner, and a new piece of paper overlapped on top of it. When this is done, with vinyl material, you’re supposed to use special vinyl-over-vinyl ( VOV ) adhesive, because regular wallpaper paste isn’t formulated to adhere to vinyl / plastic .
But even if the installer had used the correct adhesive, under humid conditions or with improper wall prep, the odds are that this wallpaper job will start to fail.
Also note dirt along the ceiling, and along the chair rail in the previous photo. General lack of maintenance and I am really suspecting lack of climate control.
The black smudges appear to be mildew coming from underneath the paper. Again, probably related to humidity.
Vinyl wallpaper is a sheet of plastic, and moisture can be trapped behind it. That can be a breeding ground for mold and mildew.
So why use vinyl wallpaper? Mainly because the surface is much more washable than most other types of wallpaper. In a business, washability is attractive.
But these property owners chose a low-end vinyl product, most likely skipped proper wall prep such as a wallpaper primer, and have not provided a hospitable environment for the paper.
There are other vinyl wallcoverings that would have held up better. For instance, vinyl on a scrim ( woven fabric ) backing, or the newer backing called non-woven , which has a 20% polyester content, and therefore less likely to wick up humidity.

From 20 Years of Red to Sweet Light Floral

February 5, 2022
Red is a classic dining room color, and painted walls served well since the late ’90’s. This homeowner has classic taste – note the elegant moldings below the chair rail and around the windows.
The update is lighter and brighter and opens up the room, making it feel larger.
Note the wallpaper around the corner on the right.
This is the paper in the adjoining hallway, which has been in place for decades. The new pattern coordinates beautifully in theme and color!
Close-up. Roses and script.
Norwall is a very economical brand (something like $25 per double roll on sale). Not my favorite quality, because the gritty paper backing can absorb humidity and separate from the thick vinyl surface, plus the seams tend to “pouch” a bit and don’t look great. But I’ve discovered that rolling a bit of wallpaper paste onto the wall under the seam areas will help to “suck down” the edges, creating better seams. I also do believe that the manufacturer has improved the substrate.
I was pleased with the way the seams looked on this install. You’re looking at a very close-up picture. Once the paper is dried and from two feet away, these seams will be invisible. In fact, the homeowner kept walking around the room remarking how she couldn’t even find a seam. Note the slightly textured surface.

The home is in the far west area of Houston.

Solid Vinyl Wallpaper = Not a Good Choice in Humid Rooms

February 4, 2022

I hung this wallpaper 30+ years ago in a 2-room bathroom. In the sink room, the paper held up beautifully. In the toilet / tub room, over the shower and in a few areas up high (where humidity collects), some seams had curled back.

What’s the difference? Two main things – composition and humidity.

In the sink room, the wallpaper was a solid vinyl. But the backing was a thin paper, or possibly a thin non-woven (part synthetic) material. In the tub room, the backing was a gritty yellowish manilla type material.

This stuff is thick, and it will continue to wick up humidity through the seams, and that leads to expansion and then shrinking as the moisture dries. Over time, that will cause the paper to curl back on itself. Sometimes, the vinyl surface actually delaminates and separates from the paper backing. In this case, both backing and surface have curled away from the wall.

I really dislike these low-end papers, and encourage clients to not purchase them. Especially not for wet areas in bathrooms. In addition to the potential to curl up, the seams never look good.

Luckily, there are plenty of viable alternatives. Wallpapers with a paper backing, or a non-woven , will hold up much better.

You Can’t Roller Skate in a Buffalo Herd …

February 2, 2022

And you can’t hang wallpaper when the house isn’t ready!

The poor homeowners of this completely renovated bungalow in the Houston Heights have had delays of up to nearly a year. Some COVID and supply-chain related. But lots more due to … well, due to tasks just not getting done. The mom pressed the contractor hard to be sure the space would be ready for wallpaper today. But as soon as I pulled up, I knew it wasn’t gonna happen.

No A/C and no heat = humidity = not good for wallpaper

Workmen in the area (my specs specify no one else on-site)

Workmen’s ladders blocking my access to rooms I am supposed to paper

Workmen’s power tools blasting noise = disrupts concentration

No running water in the house (I need to keep paper and woodwork clean)

Floors need to be sanded = dust getting onto the walls / wallpaper

High probability that someone will get handprints, paint, or other on the new paper

Yard is a mudpit = not good carrying my 50lb bucket of paste or 7′ long table back and forth

House not secure and likelihood of tools and equipment “walking off” esp. overnight

No one but me wearing a COVID-conscious mask

So, no wallpaper went up today. At first I thought I could at least get the primer up. But various factors made that not viable.

A day of work lost for me. For the rest of the week, I will have to try to find other clients who can be ready on 1-day’s notice. And reschedule these folks for later down the road.

This is a big disappointment for the homeowners, who are very much wanting the work to be finished and to move into their lovely new home.

Oh, and song lyrics compliments of Roger Miller, 1965.

Secrete Weapon for Drying Smoothing Compound

January 25, 2022

Walls need to be smooth before wallpaper can go up, both for good appearance and good adhesion. Once troweled on, the smoothing / joint compound takes a while to dry. I use fans to speed that along.

But in a small room like a powder room, this space heater really helps a lot. I close the door and let this thing run for a while. It will heat up the area quickly. The warmed air holds moisture well, and actually pulls the moisture out of the smoothing compound.

Once the air in the room is hot and humid, I’ll shut off the heater and open the door. I turn on the exhaust fan to pull, and then set a fan in the doorway blowing outside air into the room, exchanging damp air for fresh, dry air. This works amazingly well.

I keep my smaller fans running inside the room along with the heater. But my more powerful floor fan – I’ve learned the hard way that operating that and the heater at the same time will trip the electrical circuit. So it’s a juggling act between those two very useful tools.

I really like this heater, because it’s older and doesn’t have all those safety features that cause them to shut off when you want them to be on. But don’t worry – it still will stop if tipped over, and when the room gets to the set temperature, it will turn off.

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.

Space Heater Speeds Drying Time

November 28, 2021

Whether drying smoothing compound ( drywall joint compound ), or primer, hot, dry, circulating air helps speed the process.

i love this old space heater that I got at a garage sale decades ago. It runs when you tell it to, for as long as you tell it to – without “safety” measures that trip other heaters off after a few minutes. (Don’t worry – I keep an attentive eye on everything!)

The hot air from the space heater helps pull humidity out of the air, which speeds drying time.

Works best in a small room like a powder room. Close the door and let the heat build up. Use fans to move air around the room. You will feel the humidity increase as moisture is drawn from the walls. Periodically open the door and use a fan to circulate moist air out of the room.

One thing to note – which I have learned the hard way – is that this gizmo pulls a lot of electricity. And so do some fans. I can use my two box fans while this heater is running. But if I run my more powerful floor fan while the heater is on, it will trip the electrical circuit. And double-ditto if I try to use my heat gun while the heater is on.

Brightened Bathroom

November 12, 2021
Original vinyl wallpaper in this bathroom was peeling badly, due to humidity and poor ventilation. The design was dated, too. And, gee – borders are pretty much a thing of the past. Time for an update.
Old paper has been stripped off, wall has been primed. Ready for the new stuff!
What a pretty and cheery pattern! The window looks out to a lush and green backyard, and this foliage-themed wallpaper helps pull the feeling inside.
I was losing natural daylight, so the pretty blue and lime tones are not showing up well.
The colors are a little more true here. This almost looks like a water color painting!
A Street Prints is the manufacturer. This is non-woven material, also called paste-the-wall. It went up very nicely. And, because there is no vinyl and because the substrate has a higher polyester content and less paper, this should hold up much better in the humid bathroom. Nonetheless, I did lecture the homeowner to run the exhaust fan and to keep the bathroom door open for air circulation.

The home is in the League City subdivision south of Houston.