The mortar along the top of this marble tile baseboard was light colored, and I didn’t think it would look good between the black tile and the mostly-dark wallpaper. In addition, I hate trimming wallpaper against grout, because the gritty texture makes it hard to get a neat cut. And that sandy grout sure eats up my razor blades!So I applied a thin layer of joint compound over the grout, sanded it smooth, and then sealed with a penetrating primer called Gardz. This gave me a softer surface to trim against. But I was still left with a white edge. That’s what you see in the top photo. So next I used an angled artist’s brush and some black craft paint from Texas Art Supply hobby store to change the white line to black. Here’s what it looks like finished.
Here I’ve covered the wall (pale blue area) with wallpaper primer. Because I want to avoid the light wall from showing between the seams should the paper shrink as it dries, I’ve striped under the seam area with diluted dark paint from the hobby store. But you can see there are areas where the paint is not adhering. What’s up? The original surface was a gloss paint. My wallpaper primer will stick to gloss paint. But in this case, some small areas were missed when my paint roller passed over it. Then when I swiped on the dark paint, it adhered well to the matt finish of my primer. But it could not grab ahold of the small areas of gloss paint peeking out from under my primer. If this were a large area, I would be worried. Because wallpaper paste doesn’t like to stick to glossy surfaces, either. But the areas of gloss not covered by my primer are minimal, and won’t interfere with adhesion of the new wallpaper.
Dark papers are popular right now. But since wallpaper shrinks a tad when it dries, and since it’s usually printed on a white substrate, it’s possible that hairs’-breadth gaps of white wall may show at the seams. One way to prevent that is to stripe the wall under where the seams will fall with a color similar to the background of the wallpaper. Be careful to not get it too dark, as too much pigment may interfere with the wallpaper primer’s ability to perform optimally. I measured the width of the strips, and then used a laser level to guide my stripes. I use craft paint from the hobby store, and daub it on with a scrap of sponge (right) and dip into a bit of water, which I keep in a Gatorade bottlecap (left). To get rid of the white edges of the substrate, I use a bit of chalk (some folks use paint – but make sure it’s water-based …. NEVER use oil-based paint, markers, or chalks, as they will bleed onto the surface of the wallpaper). I run the chalk along the edge of the wallpaper strip, making sure to work from the back side, to prevent the chalk from working its way onto the surface of the wallpaper. Use a light touch, but cover all of the white edge. Finished wall. Don’t see no stinkin’ white gaps! 🙂 The mural pictured is by RebelWalls.com
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