Posts Tagged ‘sand’

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.

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Smoothing Sandy Textured Wall

September 11, 2018


Walls in the under-the-stairs powder room of this 1945 home in River Oaks (Houston) were covered with a sand-textured paint. The bumps would look awful under the new wallpaper, and would also interfere with good adhesion. So I needed to smooth the walls.

I troweled on drywall joint compound. Because the sand texture was so thick, the smoothing compound needed fans blowing on it overnight to become completely dry.

Once dry, I sanded it smooth. See second photo. Wiped clean of dust and primed, the walls are now ready for wallpaper.

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.