Posts Tagged ‘joint compound’

Wall Prep – Missing Chair Rail and Stain Repair

March 31, 2019


What an unexpected surprise I got when I arrived at work to discover that the chair rail in this entry had been removed (top photo). Not only did I need to figure how to get enough paper to cover the additional wallspace, but I needed to smooth over the damaged wall area where the molding had been torn off. (See previous post)
I skim-floated the wall and sanded smooth. It looked great. But brown coloring from the torn Sheetrock had worked its way through the smoothing compound (second photo). Torn drywall is not something that I would normally worry about bleeding through wallpaper (you are concerned mostly with things like grease, ink, water, tobacco, rust, and the like), but this stuff was 60 years old, so who knows what its properties and characteristics were back then? And besides, it had already worked its way through a layer of joint compound – in just one night! No sense in taking the chance that it might bleed through this nearly-white grasscloth natural fiber wallpaper.

The Gardz penetrating primer / sealer (not pictured) I planned to use on the wall would be fine to hang wallpaper on, but could not guarantee that that brown stain would not work its way through the primer and through the wallpaper.

I applied the Gardz, because it’s a great penetrating substance that seals new smoothing compound, and also provides a good surface for hanging wallpaper on. Once that was dry, I followed that with a coat of KILZ Original, an excellent oil-base stain-blocker. But wallpaper paste will not stick to the new KILZ formula (required in order to comply with current EPA requirements.

A little 3″ width around the lower center of the room with wallpaper not sticking tightly to it probably would not be problematic. But you never know, and I didn’t want a “hula hoop” of delaminated wallpaper circling the room. So once the KILZ was dry, I followed up with a coat of a wallpaper-specific primer, Romans Ultra Prime Pro 977.

Now the room is ready for wallpaper, without fear of a band of tan bleeding through the new surface.

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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.

Wall Sealing Whoops

September 26, 2018


Today I prepped a room where the drywall had been badly torn when the old wallpaper was stripped off. This happened because the original installer hung the wallpaper directly on the drywall, with no coat of paint or primer to protect the drywall.

Before I could smooth the wall surface, I had to seal the torn drywall, because moisture on the torn areas would cause the brown paper to bubble. I rolled on a heavy coat of Gardz, a water-thin, penetrating product that is designed to soak into the porous material, bind everything together, and dry hard. It is supposed to dry inpenetrable by water.

Once it was dry, I skimmed over it with joint compound (which will be sanded smooth later).

As you can see, the Gardz failed to do as claimed, and it allowed moisture from my smoothing compound to seep through it and enter the torn paper of the drywall, which then expanded and bubbled. I’ve got a big mess on my hands!

Tomorrow, when everything is dry, I will sand smooth. Usually bubbles like this dry out and then sand flat. But the large loose areas have me a little worried. They may still be loose and bubbled, and they may swell again when the wall is given its final coat of Gardz.

I may end up having to cut out some loose areas, refloat, and reprime.

Not good, because this could add a full day to this job, and because there could potentially still be unstable areas under the surface. Never good to have an unsecure surface under your wallpaper.

Getting Smoothing Compound to Dry

September 11, 2018


Textured walls have to be smoothed before the new wallpaper can go up.

Getting smoothing compound (drywall joint compound) to dry takes – dry air, moving air, air-conditioned air, heat …. and a lot of time. Today’s job had particularly thick textured walls, which would take a long time to dry.

So I hastened things up with a few accessories. Here you see one box fan on the floor aimed at a wall, another box fan on the ladder aimed higher on a wall, a very strong black floor fan shooting dry air into the room, and a space heater under the sink cranked to “high.”

When I shut the door, the warmth from the space heater collects in the air, and pulls moisture out of the smoothing compound. Then I will open the door and let the floor fan pull dry air-conditioned air from the hallway into the room, pushing the hot, humid air out.

Done enough times over a long period of time, you can get smoothing compound to dry more quickly than it would on its own.

Contractors and Painters Should NOT Prep Walls for Wallpaper

July 14, 2018


This home in the Meyerland neighborhood of Houston was flooded during Hurricane Harvey, and has been redone, and is now ready for final touches, like decorating, i.e. – wallpaper!

The first three photos show how the contractor left the walls. It’s hard to conceive how anyone could think these walls are “ready for wallpaper.”

What you are looking at is where the contractor ripped off the top, inked layer of the original wallpaper. Most of them don’t realize that there is a backing layer of paper that is left on the wall, that should be removed, too. Simply soaking this with a wet sponge will reactivate the paste and allow the paper to be removed easily, and with no damage to the wall (esp. if there is a good primer underneath the paper). Read my page to the right “How to Strip Wallpaper” to see how this should be done.

Instead, this contractor left the paper backing on the wall. Some of this porous backing is exposed. Other areas have been covered with the paint that was used on the woodwork. This solvent-based paint “raises the grain” of the surface it’s applied to – see all the hairy fibers from the wallpaper backing that have gotten stuck in the paint and raised up? Some of them are more than 1/4″ high. They create a gritty feeling on the surface, like really coarse sandpaper.

The surface is uneven, and the bumps will show under the new paper. The unevenness also means that areas of the paper will not be able to contact the wall, so there will be gaps and air bubbles and poor adhesion. The backing of the original wallpaper has been exposed, and when new, wet, pasted wallpaper gets placed on top of that thirsty paper backing, it will absorb moisture, expand, and bubble.

I had three missions. 1.) Seal the surface 2.) Smooth the surface 3.) Prime with a wallpaper-appropriate primer.

I rolled on a coat of the penetrating sealer Gardz to seal the surface, so that my following treatments would not cause the paper backing to bubble. When that was dry, I skim-floated the wall with a coat of joint compound. In the areas where the hairs were 1/4″ high, the skim coat was pretty thick, and took a good while to dry. Once that was dry, I sanded it smooth, then vacuumed the dust of off the floor, used a damp sponge to wipe residual dust off the walls, and then followed up with another coat of Gardz. It will soak into the joint compound and dry hard, forming a stable surface for the new paper to adhere to.

The last photo shows the wall once I finished.

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.

Rubbery, Problematic Smoothing Compound

June 15, 2018


I was stripping wallpaper by peeling off the top vinyl layer and then soaking the paper backing to reactivate the paste so the paper could be removed from the wall – and ran into this.

It looks like the previous installer smoothed the wall (which is good), but used a latex spackling compound instead of the more typical joint compound. The latex became wet from the water I was using to soak off the wallpaper, and began to pull away from the wall.

This is all bad, because it leaves a bumpy mess on the wall that will show through the new paper. But worse is that it is an unstable surface for the new paper to try to hold on to. When wallpaper paste dries, the paper shrinks and puts tension on the surface below, particularly the seams. If the surface is not solid, the layers can actually come apart (delaminate) resulting in curled or gapping seams.

This is not “loose paper,” and cannot simply be glued back down. The different layers inside the wall are actually coming apart, and will require a lot of work to make the wall sound again.

Once the paper was off and the wall was good and dry, the layers seemed to adhere to each other better, and the wall felt more solid. The way I treated it was to roll on a coat of Gardz, which is a penetrating sealer that binds things together. It did a good job. Then I skim-floated over that with joint compound, which, when sanded, would leave a nice, smooth surface.

One more coat of Gardz on top of that, and the wall was sound and ready for wallpaper.

Repairing Damage from Hurricane Harvey

April 27, 2018


This home in the Champions Forest area of north Houston received flood damage after Hurricane Harvey. The bottom 2′ or so of drywall had been cut out and replaced by the restoration contractor. The only thing is, the new drywall was recessed back about 3/8″ from the existing drywall. Even though this was near the floor in the niche behind the refrigerator, the homeowner didn’t want to have a difference in wall height, nor a mis-match in the wallpaper pattern.

So I used joint compound (“mud”) and drywall seam tape to bridge the gap and to float out the discrepancy. It took three coats, and several sandings, plus a sealing primer, but the finished wall is pretty even and smooth. (2nd photo)

There wasn’t enough left over paper to replace the whole alcove, so I used scraps to piece in the bottom area. Rather than make a straight horizontal cut 2′ above the floor, it’s less eye-catching to have the patched areas run along a feature of the design, such as the vines and branches in this pattern. (3rd photo)

Once the new strips were smoothed into place (4th and 5th photos), the patched areas are virtually undetectable.

Sometimes people complain about having left over wallpaper. But here’s a good example of why you should. (last photo) This homeowner had kept all her leftovers in their original wrappings and in their original box, in a climate-controlled environment (not the garage or attic), and she had what was needed to make this repair (and several others around the room that are not shown here).

Compound in Electrical Outlet Could Cause Fire

March 26, 2018


Somehow, workmen jammed joint compound into this electrical outlet box. This water-based material resting between the connectors on the electrical outlet could serve as a conductor – and could have easily short-circuited the circuit … which could have blow out every light and electrical appliance on that circuit. As well as potentially started an electrical fire.