Hoping to Rectify Failure (Humidity Causes Poor Seams)

Humidity is the great enemy of wallpaper. In addition, the lower-end, pre-pasted, solid-vinyl papers with the gritty manila paper backing are not a good choice, in my opinion, in any room, but particularly not humid rooms like bathrooms. This house on the beach with irregular climate control spelled double trouble.

This home on Pirate’s Beach on Galveston Island (south of Houston) was on the beach, so was exposed to lots of humidity. In addition, because the homeowners use it only sporadically, they turn the air conditioner off or set it to a run less while they are away. This means that the home fills up with humidity. And even when the A/C is running, air circulation in this room is poor.

Metal elements such as the light fixture and screws holding things into the walls were rusted. Mildew was found behind some sheets of wallpaper. And the wallpaper itself was curling at the seams – a result of the paper backing absorbing moisture from the air, expanding, and forcing the vinyl surface to curl backward at the seams. (Read more about this on the page to the right about vinyl wallcoverings.)

Another factor for the poor performance of the original vinyl wallpaper was that the walls had not been primed, but the installer put the vinyl paper on top of new drywall. And nothing was done around the shower to protect the paper from splashing water.

I stripped off the old vinyl wallpaper, washed the walls with bleach to kill the mildew, and primed with the penetrating sealer Gardz. Once the new paper was up, I ran caulk along the top of the vanity backsplash, and all along the shower and tub, to prevent splashed water from wicking up under the paper.

The new wallpaper is a thin non-woven material that is “breathable.” No wallpaper is going to hold up under very humid conditions. But this one has a much better chance of staying nice and flat for many years.

The new wallpaper is very similar in appearance to the original, and keeps with the beachy feel of the home. It is by Brewster, in their Chesapeake Bay collection, in the Easy Walls line, and is reasonably priced. It is a pre-pasted material. I did augment the manufacturer’s paste with a .

In the photos, the paper looks blotchy. That is because it is still wet; it will be nice and white when it’s finally dry. The drying time worries me, though, because after six hours, even some parts of the first strips were not dry. This is a real indicator that the room has some serious humidity and air circulation issues.

Treating Mildew on Walls Before Wallpapering

When the old wallpaper was pulled off, surprises were revealed! Here you see mildew (don’t worry, it’s not mold) that had grown under the paper where a water leak had lead to damp conditions, probably exacerbated by the thick, non-breathing, vinyl wallpaper.

Mildew will bleed through wallpaper, and it can also create a powdery colony that will not provide a stable surface for the wallpaper to grab ahold of.

To kill the mildew, I washed it with full-strength bleach. When that was dry, I went over it with an oil-based stain blocker. I like the product KILZ Original.

Killing Mildew

Digital Image

Digital Image

Yeowee … this wall has a lot of issues with torn Sheetrock (the dark brown areas), but more important – the black stuff that you see in the top photo is mildew.  Not good.  Mildew is a living organism, and it can grow and grow.  It’s powdery, and so as it spreads across the wall, it can separate from the wall (delaminate), which means that the wallpaper is at risk of falling off the wall.  Mildew can also travel right through wallpaper, creating a ghost-like shadow of dark – or sometime pink – discoloration.

Mildew is usually caused by moisture.  It’s not clear what caused the problem in this powder room in a 1957 home in the Tanglewood area of Houston.  It could be a leak in the wall (pipe, window, roof, lawn sprinkler outside hitting the wall).  Or it could be that the solid vinyl surface of the previous wallpaper prevented air from getting to the backing, and so that it could not dry out, and then it held dampness against the wall – which created the perfect breeding ground for mildew.

Getting rid of mildew requires a few steps.  First, it must be wiped and scrubbed with chlorine bleach, then rinsed clean.  Once the wall is dry, a coat of a quality stain-blocker is applied.  I like oil-based KILZ Original, but other options include Zinsser’s B-I-N stain blocker.

Once the stain blocker is dry, the wall can be coated in a wallpaper primer.