Posts Tagged ‘joint compound’

Smoothing Walls – I Can’t See What I’m Doing!

September 15, 2021
To smooth textured walls so you won’t see bumps under the wallpaper, I use this trowel to spread on Sheetrock brand Plus 3 lightweight joint compound (a.k.a. “mud”). This is called “skim-coating” or “skim-floating.”
Problem is, the mud is the same color as the wall. I can hardly see what I am doing! Once it dries it will turn white. But until then, I’m fumbling along.

Smoothing Textured Walls = Sanding Dust

May 19, 2021

This master bedroom had textured walls that needed to be smoothed before the wallpaper could go up. (Texture looks bad under the new wallpaper, plus it interferes with good adhesion.)

I “skim-floated” the walls with drywall joint compound (what we call “mud”). This is akin to troweling on plaster.

Once that was dry, I sanded the walls smooth. In the first photo, you see the amount of dust that is created!

In the second photo are my “sanding sponges.” Some are coarse, some are fine, and one is angled, all with specific uses. These became available maybe 25 years ago, and are a huge improvement over the sandpaper-wrapped-around-a-block-of-wood that everyone used previously.

The putty knife is used to knock off big globs or high ridges, before hitting the wall with the sanding sponges.

Actually, I used to use a hand-held electric sander. That tool was fast, but it put a whole lot of dust into the air, and it traveled all over the room.

The sanding sponges are hand-operated and don’t throw dust up into the air. Also, manufacturers have made improvements to the joint compound formula which encourage the dust to sink to the floor rather than become air-borne.

You still end up with a lot of dust, though. And it does sift all over the room.

No problem. I simply bring in my Shop Vac (not pictured) and vacuum up all the dust. There’s still residual dust, so I use a damp rag to wipe dust off the floor, and a damp sponge to remove dust from the walls. (Important, because wallpaper will not adhere to a dusty wall).

Note that the photo shows an empty room. In rooms that have furniture, I cover it with painter’s plastic. And in most situations, which are usually one accent wall, I put up a sheet of plastic along the wall, draped from ceiling to floor, which contains dust to the 3′ along the wall, and prevents dust from getting to the rest of the room.

I also want to note that I am a big proponent of drop cloths. The reason you don’t see them in this scenario is because you can’t vacuum dust off a dropcloth, because the dropcloth gets sucked up into the vacuum nozzel. Much easier to vacuum dust up off a solid floor, and then wipe up any residue.

I also want to note that all my ladders wear “booties” / baby socks on the feet, to cushion the client’s floors and protect against scratches.

Getting Smoothing Compound to Dry Quickly

May 5, 2021

In my previous post, the wall had the thick, knock-down texture that is typical in new tract homes in the Houston area. You can’t hang wallpaper on this texture, because it looks bad under the paper, and because it interferes with good adhesion.

The solution is to “skim-float” the walls with joint compound, a.k.a. “mud,” which is much like plaster. The mud needs time to dry. When the texture on the walls is super heavy, as in this home, I usually let the smoothing compound dry overnight. That does add an extra day – and an extra day’s cost – to the job.

To save these homeowners from paying for that extra day, we pulled out all the stops. In this photo, you see my two box fans and my heavy-duty black floor fan blasting away at the wall. In addition, we have the room’s ceiling fan. And, in the lower left corner, the homeowner added his yellow “squirrel cage” fan.

Once the wall got half-way dry, I used my heat gun – the yellow gizmo you see lying on the dropcloth, which I call “The Great Persuader” – to speed up the drying process in stubborn areas.

Still, it took a long time for the wall to completely dry. Next I had to sand the “mud” smooth, vacuum up the dust, wipe residual dust off the wall with a damp sponge, and then apply a primer.

Start to finish, all that prep, plus hanging the paper – a whole 3.1 strips in 35 sq. ft. of space – took nearly eight hours.

Going For More Of The Same

February 9, 2021

I hung the original wallpaper in 2014, when the house was first built. The PEX water lines used in the home (flexible hoses instead of PVC pipes) were new at the time. Tragically, after a few years, the lines used in this home failed and caused leaks all over the house. Replacing all the water lines required cutting holes in MANY places throughout the home.

You can see in the photos where the plumbers cut out drywall and then patched it back in. This company actually did a good job of removing the wallpaper in the areas of their repairs.

Unfortunately, with the amount of wallpaper that was left over from 2014, I was not able to do repairs. The entire room had to be repapered.

The homeowner loved the pattern and wanted to keep it. It was still available, so she bought enough to repaper the room.

For various reasons, the original wallpaper was much more difficult to get off the wall than I expected. I could have gotten it off – but it would have taken about two full days.

So I opted to hang over it. It’s important to skim-float over the seam areas. First, because the seams will leave a little ridge that will telegraph through and show under the new paper. But also, because as wallpaper dries, it shrinks and puts tension on the seams. There is always the potential that this tension will cause the the surface below to pull away from the wall, and especially so if there is a weak area such as a seam. So you always want to avoid putting a seam on top of a seam.

So I skim-floated (do a Search here to learn more) over the seams, as well as over the patched areas left by the plumbers. See photos. Then I sealed the walls with Gardz, a product that penetrates and seals porous materials – like drywall joint compound and like this traditional British pulp wallpaper. Because it soaks in and dries hard, it helps to prevent moisture from paint or wallpaper paste from soaking through, and thus prevents bubbling of the underlying surface. That’s why this product is primarily used for sealing torn layers of drywall.

Although a bit glossy for my liking, Gardz is also a good primer to hang wallpaper on.

Interestingly, the expansion rate of the new wallpaper was a bit less than the original, and so the seams fell about 1/4″ to the right of the original seams. This reduced the worry of seams falling on top of seams and causing lifting.

It was a complicated room, and the paper was thick and stiff and difficult to work with. Prep took one day, and it took me two additional days to hang the paper (16 single rolls – 8 double roll bolts).

The wallpaper is in the line of Nina Campbell, by Osborne & Little, a British company. While most British papers these days are printed on an agreeable non-woven substrate, this one is a traditional, old-school British pulp … thick, stiff, difficult to fit into turns and angles, easy to tear, easily stained, non-malleable, plus the factory’s trimming roller blades must have been dull or wobbly, because the edges were not cut perfectly straight, which meant the seams had some “gaps and overlaps.”

Still, the finished room did look pretty darned good – even if it looks exactly the same as it did in 2014.

But that’s exactly what the homeowner wanted. So all is good and mission accomplished!

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.

Smoothing Suburban Heavily Textured Walls

November 1, 2020


In the tract homes in new subdivision developments all around Houston, it’s very common that the builder will use a heavy wall texture like this. You can’t hang wallpaper on this, because the bumps and dips will look horrible under the paper, and also they will impede good adhesion.

So the walls will need to be smoothed. This is accomplished by “skim-floating” or “skim-coating” the walls with joint compound. I do my own prep. And, as I like to say, I’m better at it than any “guy” you can hire. 🙂

The third photo shows the wall with half in original condition, and half with the smoothing compound applied over it.

Some people use a wide taping knife to spread the “mud,” as we call it. But I prefer the trowel shown in the fourth photo, because I am closer to it and can see everything that I am doing, and also I feel the position of the handle gives me better manual control.

Sometimes, using fans and playing with the A/C or heat systems, the compound will dry in a couple of hours. But with texture this heavy, the material must be left to dry overnight.

Tomorrow morning, I will sand the walls smooth, vacuum up the dust, wipe residual dust off the wall with a damp sponge, and then roll on a primer. Once that dries (again, call in the fans!), the wallpaper can go up. The second-to-last photo shows it finished and ready for wallpaper.

The last photo shows the brand I prefer, USG’s Sheetrock brand “Plus 3,” which you can find at most big box stores and most paint stores. It sands a lot more easily than the standard joint compound in the red, white, and green box.

Sometimes (Rarely) You Have To Hang Over Old Wallpaper

September 18, 2020


It’s always best, for many, many reasons, to remove old existing wallpaper before hanging new. Especially if that old paper is vinyl or non-woven or thick / textured.

But sometimes, it just isn’t feasible. Here, the original installer didn’t use a primer, so his wallpaper bonded to the bare Sheetrock and would not come off without taking the top layer of drywall along with it. I worked at it for an hour, but only removed about 10 square feet – and much of that included damaged drywall.

So, time to try another tact. This method only works with paper (not vinyl or anything thick or textured), and the original paper has to be tightly secured to the wall. First, I removed any loose areas – usually over joints in the drywall that have been coated with joint compound (it’s porous and sucks the paste off of the wallpaper).

Then I took joint compound and skim-floated over any uneven areas or any sections of torn drywall, and all wallpaper seams. Seams may feel flat, but once new wallpaper is on top of them, the vertical lines of seams will telegraph through and be visible.

Once that was dry, I sanded smooth and “feathered out the edges,” then wiped off all dust with a damp sponge. See top photo.

Then I rolled on my favorite wallpaper primer, Roman Ultra Prime Pro 977, and made sure to cut in around the edges with a trim brush. This primer sticks to just about anything, including the light acrylic protective coating on most paper wallpapers, such as what I had today. It doesn’t penetrate the joint compound and cause the torn drywall to stretch or wrinkle. Nor will it allow moisture from the new wallpaper paste to penetrate through. And it’s lightly pigmented, so it works well under thin wallpapers.

Plus, it is formulated to receive and hold wallpaper, makes installation easier in many aspects, resists tension on the wall as wallpaper dries and shrinks, and eases removal of the wallpaper in the future.

Once the primer is dry, the room will be ready for its new wallpaper.

Mirror Tar Bleeds Through Wallpaper – Prevention

June 18, 2020



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.

Weird Cracks

March 24, 2020


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.

Washing Texture Off of Walls

March 5, 2020


The owners of this new-build home in the Garden Oaks neighborhood of Houston knew that they wanted wallpaper in the dining room and powder room. So they instructed the builder to not texture the walls.

Well, as often happens, the drywall/paint guys didn’t get the message, so while they were spraying texture on the other walls in the home, they also textured the dining and powder rooms (sorry, no picture).

But – they got stopped before they primed or painted. This is good.

The textured surface had to be smoothed before wallpaper could go up. I’m quite good at skim-floating, and I quoted the homeowners a price for me to float and sand the walls smooth.

But the homeowner is also pretty handy. He opted to smooth the walls himself.

Since no primer or paint had been applied, the texture on the walls was raw mud (drywall joint compound). With no coating on it, this stuff is water-soluble. That means that the homeowner could simply wipe the walls with a wet sponge to remove the texture.

Well, it’s actually a bit more than that. You have to wet the walls well, and keep on scrubbing, to the point where the joint compound / texture softens up and can be scraped off the wall with a stiff putty knife, or scrubbed off the wall with a drywall sponge.

And that’s what the homeowner did. He did such a good job that he cleaned the walls all the way down to the bare drywall. That’s what you see in the first two photos. This guy was way more thorough and meticulous than any “professional” I’ve seen out there.

The best primer for bare drywall is Gardz (third photo). It penetrates and seals both the paper face of the drywall, as well as the joint compound “mud” that is troweled over the joints and tape (see white areas in photos).

So my task for today was not to work on smoothing the walls, because the homeonwer had done such a great job of that. OK, well, I did do a little tweaking in a few areas. But primarily, what I did today was roll on (and cut into the corners and edges) a good coat of Gardz.

Besides sealing drywall, Gardz is a good primer for wallpaper. So once the primer was applied and then dried (about an hour), the room was ready for wallpaper.