Posts Tagged ‘mud’

Getting Smoothing Compound To Dry

June 13, 2019


The walls in this powder room were textured. (see top photo) To ensure that the new wallpaper looks good, and that it has a solid surface to cling to, the walls need to be smoothed. This is called floating, or skim coating, and I do a lot of it here in Houston. To do that, I trowel on a plaster-like substance, let it dry, then sand it, vacuum up the dust, wipe residual dust off the walls with a damp sponge, and then prime.

What takes the most time is waiting for the smoothing compound (drywall joint compound, which we also call “mud”) to dry. If the texture is heavy, often it has to dry overnight. The downside of this is that it adds an extra day of labor and expense. But when the texture is lighter, the drying can be speeded along.

In the second photo, you see some of the ways I get mud to dry more quickly. On the counter* you see two box fans, and on the floor is a much stronger fan. On the counter is also a space heater. Hot air in the room absorbs moisture, sucking it out of the wet smoothing compound. I let the room heat up, and then I have to open the door and let the moist air out – over and over again.

The yellow objet on the floor is a heat gun. A heat gun acts like a hair dryer on steroids, and can get small stubborn areas to dry pretty quickly.

A few other things help speed drying … Walls coated with flat paint will dry more quickly than with glossy paint. And having the air conditioning and / or heat cranking away will help, because, while regulating the temperature, these climate-control systems also pull humidity out of the air. I also like to turn the HVAC system’s fan from “Auto” to “On,” so that air is circulating continuously, which also pulls humidity out of the air and helps the walls to dry.

*I normally keep a dropcloth on the vanity counter. But the vibrating fans can cause the dropcloths to slip, and you don’t want anything crashing down on the homeowner’s countertop. I do have lengths of self-grip shelf liner that help keep the fans from moving around too much.

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What’s Missing?

March 29, 2019


Here’s a wall in an entry in a 1960’s ranch style home in the Briargrove neighborhood of Houston. See that brown line around the middle? Someone has removed the chair rail.

All that is fine and good – but no one told me that the chair rail would be removed, and that they wanted their wallpaper to go floor-to-ceiling.

So, unfortunately, when I measured this room (while the chair rail was in place), I did not figure for enough paper to do the full-length walls. In other words, they don’t have enough paper to do the job.

The other thing is, the walls have a light-to-medium texture, and I planned to skim-float them to smooth them before the paper goes up. That was to take the first half of the day, and I would hang the paper in the afternoon.

But removing the chair rail changes things … Because when the chair rail came off, it took many 50 years’ worth of paint with it – about 1/4″ worth – which means that the area of the brown horizontal stripe needs a thicker layer of smoothing compound than the rest of the walls. This means that it needs more time to dry. A LOT more time, like at least overnight, or even better, a second day. (Quick dry hot mud was not an option, for several reasons.)

This means that this one-day job now requires two, and it means that the homeowners will not get their room done as they expected, and will have to put up with me being there another day. It’s also disrupted my schedule.

Good communication at the beginning and when I first visited this site would have prevented this, kept us on-schedule, and kept everyone happy.

Contractor Patches On Top Of Wallpaper – Bad Idea

February 19, 2019


This home experienced a water leak, and the bottom 2′ of drywall had to be cut out and replaced. When taping-and-floating in the new drywall, the contractor didn’t bother to remove the existing wallpaper, but put his smoothing compound right over it. This is bad enough if the old paper is paper, but this wallpaper is vinyl – something you really don’t want buried under layers of joint compound and new wallpaper.

Vinyl is shiny, and few materials will stick well to it over a period of time. It is also thick, and that increases the likelihood that seams will pop up, even if they are buried under this “mud,” as we call it.

So I took a razor and cut above the contractor’s patch. Then I stripped off all the wallpaper above the patch. This left a difference in height between the patched area and the newly-stripped area, which would create a visible ridge under the new wallpaper. So then I took my own smoothing compound (joint compound) and floated over his patch and the now-bare wall, to eliminate any uneven areas.

Waited for it to dry, sanded smooth, removed dust, primed with Gardz, and finally was able to hang the new wallpaper.

This took a LOT more time than I originally planned for this job, but it was worth it to keep vinyl wallpaper from being underneath the new paper, and to prevent any bumps or irregularities from showing under the new paper.

If You Want Smooth Walls, You’ve Gotta Put Up With a Little Dust

July 7, 2018


The walls in this house had a pretty heavy texture, which I wanted to smooth before hanging their wallpaper. This involves skim floating the walls with joint compound (commonly referred to as mud). Do a search on those terms here to learn more about this process.

Once the mud is dry, I sand it smooth. This makes a dust – and the thicker the wall texture, the more the dust. Here you see what has accumulated on the floor after sanding.

Don’t worry – I bring in my Shop Vac and clean all the dust up.

Smoothing Textured Walls

June 16, 2018


I like walls to be nice and smooth when the wallpaper goes up, first so the texture doesn’t show under the new paper, and second so the paper has an intact, flat surface to grab ahold of. When homes have textured walls, I skim float them with joint compound (which we calls mud) to smooth them.

To skim float, I use a trowel to spread the smoothing compound onto the walls. In the top photo, the upper portion of the wall has been skimmed, and you can see the compound drying around the edges and in high areas. It goes on grey, and when it’s dry, it will turn white. The second photo shows the box that the mud comes in, enclosed in a plastic bag, to retain its moisture.

To help speed the drying process along, I set fans up blowing on the walls, as you see in the second photo. I have three fans, and they will be positioned differently for maximum air blastage. Having the air conditioner cranking away and the house fan on also help to circulate air and pull humidity out of the air. In small powder rooms where the door can be closed and the climate supervised closely, I get a space heater going, which also helps pull humidity out of the air. For stubborn areas, I get out the heat gun – it’s like a hair dryer on steroids. 🙂

Once the mud is dry, I sand the walls smooth, then vacuum up the dust that falls to the floor, then wipe residual dust off the walls with a damp sponge, and then finally prime the walls. For this application, I use Gardz, a penetrating sealer which soaks into the joint compound and binds it together, and which is also a good primer to hang wallpaper on. Sorry, no photo of the Gardz or of the finished wall – but you can Search here to find previous posts.

Air Bubbles from Latex Paint

June 13, 2018

The walls had a light texture covered with latex paint, so I skim floated over the walls to smooth them. When the wet smoothing compound got onto the wall, the latex paint absorbed moisture, expanded, and created these bubbles. It’s called “off gassing.”

After the mud dried and was sanded, most of the bubbles disappeared, but some rings were still visible. When I primed with Gardz, a water-borne penetrating sealer, many of the bubbles raised their heads again.

I will have to see if they dry flat over night, or if I will have to use my putty knife to knock them off in the morning. I don’t want bumps showing under the new wallpaper!

Prepping Walls When Existing Wallpaper Won’t Come Off

July 18, 2017

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Almost always, when homeowners are switching from an outdated wallpaper to a new pattern, I am able to get the old paper off the wall. But twice this week I have run into papers that would not come off the wall – at least, not without causing significant damage to the Sheetrock or creating other problems. Sometimes it’s because they were installed improperly in the first place. And other times it’s just the nature of the beast.

Either way, it is possible to hang wallpaper over old existing wallpaper – IF the walls are prepared correctly.

In these two rooms, I used joint compound (“mud”) to skim float over the seams in the original wallpaper, to ensure that they would not telegraph through and show up as vertical lines under the new wallpaper. These are the white stripes and patches you see in the photos.

Then I sanded the mud smooth, making sure that the edges were feathered out, so the joint compound patch would not be detectable under the new wallpaper. I used a damp sponge to wipe dust off the sanded areas.

The next step was to seal the walls with a penetrating sealer called Gardz (by Zinsser). Gardz is a thin liquid sealer that soaks into the surface and binds it together. It dries hard, and prevents moisture from passing through.

In other words, you can hang wallpaper that is wet with paste on top of this primer, and not worry about moisture passing through and causing the original paste to loosen, or the original paper to swell and bubble away from the wall.

In addition, Gardz dries with a crystalized molecular surface that is ideal for wallpaper and its paste to “bite into” and “get a hold of.”

Bottom line – Gardz is a super fixer of problem walls, it’s a wonderful sealer, and it is a great primer for using under wallpaper.

I’m Scared Of This Blue Dot

June 8, 2017

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I am going to hang grasscloth in this large master bedroom in the River Oaks neighborhood of Houston. To smooth the textured walls, I skim-floated the walls with “mud” (joint compound). As I was sanding the compound smooth, I discovered this small blue spot. It might be ink. Or maybe some cleaning solution, or a cosmetic or perfume, or some other agent. SOMEthing was on the wall before I applied the smoothing compound, and bled through.

Whatever it is, it worked its way through the smoothing compound and up onto the wall surface. If a substance works its way through the wall surfaces, you can be sure that it will also work its way through the new wallpaper.

To prevent this, there are a couple of options. One is to cover the area with a stain-blocking sealer. I love oil-based KILZ Original. Another product is BIN by Zinsser, or 123 also by Zinsser.

But in this case, since it is just a tiny dot, I decided to use a Stanley knife to dig out the stain. Gone. Done. No worries about anything bleeding through the wallpaper.

If the new wallpaper had a smooth surface, I would patch over the hole and sand the area smooth, and spot-prime. But since the new wallpaper is a rough-textured grasscloth, this 1/4″ dent in the wall will not be noticeable, so I’m going to leave it as it is. Tomorrow, before hanging paper, I will double check to be sure no additional blue stain has worked its way out from hiding.

Fixing a “Hot Mess”

April 18, 2017

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The homeowners of this house in Fleetwood (west Houston) tried to remove the wallpaper from their powder room on their own. They did a reasonably good job at the start, but soon realized that they were in over their heads.

In the top photo, they have removed the top layer of wallpaper from the wall on the left. The problem came when trying to take off the white backing layer. Their efforts resulted in torn drywall (second photo). Torn drywall is very bad, because it will leave uneven areas under the new wallpaper / paint. Worse, it will bubble when the moisture from the wallpaper paste or latex paint touches it, and that will leave bubbles under the new wallpaper / paint.

These homeowners were smart enough to stop before more damage was done, and called in the pros (me).

I finished stripping off the old wallpaper, using methods that caused less damage to the drywall. There was one patch of original wallpaper, a foil-type that dated back to the build date of 1976, that would not come off without a lot of damage to the wall. I left that section on the wall.

Once all the paper was off that would come off, I sealed the torn drywall and other unstable surface areas with Gardz, a penetrating sealer. Once that was dry, I skim-floated the entire room with “mud,” (joint compound). When that was dry, I sanded the surface smooth. Then I vacuumed up the dust, then wiped any residual dust off the walls with a damp sponge.

Lastly, I rolled on another coat of the penetrating sealer Gardz. It will dry hard and tight, preventing the torn drywall from bubbling, and holding all the loose or unstable areas together. It is also a good primer for wallpaper, so tomorrow the walls will be prepped and ready for their new décor! See last photo.

Using 20-Minute “Mud” to Repair Sheetrock Damage

March 31, 2017

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When the homeowners had their powder room vanity top replaced, the shorter new backsplash left a 1″ area of torn drywall around the top of the new backsplash. There was a height difference between the drywall and the wall (which was covered with at least two layers of old wallpaper). This needed to be evened out before the new wallpaper could go up.

Because torn drywall will bubble when it gets wet, I used a penetrating sealer called Gardz to prevent this by sealing the raw area. Once that was dry, I used 20-minute joint compound to “float” over the damaged areas.

The bag says “5” (see photo), but that is misleading. What they mean is that you have five minutes to mix the powdered material with water, stir smooth, and then work with the stuff, before it gets stiff and hard. The actual drying time is more like 10-20 minutes, and sometimes longer.

Once it’s dry, it can be sanded smooth. Wipe off the dust with damp sponge, let dry again. Then it can be sealed with a primer, and I like the penetrating sealer Gardz, once again, to seal this porous joint compound material.