Here I’ve rolled on my favorite wallpaper primer , Roman Pro 977 Ultra Prime . Since I’m going over flat water-based paint, I expected my primer to dry smoothly and quickly. So I was surprised when I looked back 30 minutes later and saw that some areas were wet and had actually thickened up a bit and pushed away from the wall. Here is looks like it’s actually sweating . This is most likely due to what is on the surface below – including below that surface. In other words, I think somewhere along the line, the wall was painted with semi-gloss paint. The gloss finish won’t allow moisture to pass through it, so the moisture stays on the surface longer. Possibly also, something in one or more of the base surfaces holds on to moisture , so that it is not allowed to dry and evaporate into the air . These principles would hold true even if another coat paint , even matt finish paint, was applied on top. I ended up bringing a fan in from my van and aiming some moving air onto that wall to speed dry time .
This is a typical wall texture provided by many builders of new tract homes in the suburbs of Houston. Wallpaper doesn’t look good hung over this texture, because the bumps will show through. And the high-and-low ridges and dips interfere with good adhesion to the wall. So this accent wall will need to be skim-floated to smooth it before the wallpaper can go up. In addition, this wall started out with a semi-gloss paint. I worry about my materials being able to stick to a glossy surface. So, before applying the smoothing compound, I am priming the wall with something that will stick to the gloss paint, as well as provide a matt finish for the smoothing compound to adhere to. I’ve discovered that my favorite wallpaper primer also works great for this purpose. It sticks to just about anything, and dries almost dead-flat. I like Roman Pro 977 Ultra Prime. I use a trowel (top) to spread on the smoothing compound. The 3″ stiff putty knife is used to knock off big-ish chunks on the wall, or bits of grit. I use the 1 1/2″ flexible putty knife to apply the smoothing compound in tight spots like around electrical outlets or between a door molding and a wall corner. The smoothing compound I use is drywall joint compound, and I like the Sheetrock brand Plus 3 version. Search hear (upper right) to see previous posts with photos of this material. Bottom of photo – trowel sticking to the wall shows you just how tacky this stuff is. Above that are blobs of the smoothing compound waiting to be spread around, and a little bit on the left initially smoothed onto the wall. At the top of the wall you see a section that I have already covered with the smoothing compound. This will dry overnight, and I will sand it smooth tomorrow. Sometimes I can float a wall, get it to dry, sand it smooth, prime, and hang the paper all in one day. But this texture is so heavy that more time is required for it to dry, so it will need an overnight sit. Some fans, plus the home’s heat and/or air conditioning help to pull moisture out of the smoothing compound and hasten dry time.
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