Posts Tagged ‘mildew’

Mildew on Wall Indicates Moisture Problem – Somewhere

October 9, 2018


I have just stripped off a solid vinyl wallcovering that had been up for at least 10 years, possibly twice that. The entire wall was covered with mildew. The mildew was present just on the exterior wall; not any of the walls that connected to interior areas of the home.

Mildew breeds when there is moisture. This indicates that there may be a leak in the home’s siding, or a leak in a window on an upper floor allowing water to get inside the wall and into the drywall. Another possibility is that plumbing inside the wall could have sprung a leak, and also caused the drywall to become wet.

Because the wallcovering was solid vinyl, it trapped the moisture between the wall and the wallpaper, and that allowed mildew to grow between the two surfaces. I’m rather surprised that the mildew didn’t penetrate through the wallpaper and show on the surface. The drywall didn’t appear to be soggy or rotted or compromised.

Another reason why I don’t like solid vinyl wallpapers.

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Hoping to Rectify Failure (Humidity Causes Poor Seams)

August 24, 2018

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

July 11, 2018


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.

Ink Spots Bleed Through Wallpaper

July 8, 2018


Well, this has been a month of issues with stains on walls! I was smoothing these textured walls with joint compound, and noticed some red splotches on the paint. I studied them, but decided they were paint, which is stable and not a problem. But a little after I had skimmed over the spots, I looked again and noticed that the red color had bled through.

Evidently it was ink, or lipstick, or child’s crayon, or some other such substance. Along with rust, blood, water, oil, mold and mildew, and a few others, these materials will bleed through paint and wallpaper. It might not happen right away, but eventually you will notice stains on the paper.

These stains can be sealed with a stain-blocker. I like oil-based KILZ Original, but the shellac-based BIN primer is good, too. Water-borne sealers may be environmentally-friendly, but I don’t trust them to work as well.

But in this case, I preferred to just get rid of the questionable areas. I took a knife and dug out the part of the wall that had the red spots. Those are the chips I am holding in my hand. Then I skim-floated over the area to smooth it, and proceeded with my wall prep and wallpaper installation.

No more red spots showed their faces. ūüôā

Mildew, Bleach, KILZ

June 7, 2018


Whooah! I stripped off wallpaper from this wall around a window in a home that had some water damage from Hurricane Harvey, to find this black powdery stuff – mildew. You don’t want to put wallpaper over a wall that has mildew, because the black stuff will continue to grow. And because it’s chalky / powdery, it the wallpaper will not stick to it. And it will also work its way through the wallpaper and create a stain on the surface.

I use bleach to kill the mildew and remove it from the wall. Once dry, I use KILZ Original oil-based stain blocker to seal the surface. In this case, I also skim-coated the wall, to make it nice and smooth. I will follow that with a coat of Gardz, a penetrating sealer that is also a good product to hang wallpaper on.

Mildew!

December 13, 2017


You can clearly see the mildew on the wall that was revealed when I removed the wallpaper. It shows up as the black rings / circles.

The mildew was caused by moisture trapped in the wall by both a leak in the roof or siding, and a leak from a bathroom that crept under the floor – compounded by being trapped inside the wall by a solid vinyl wallpaper that would not breathe or allow air to pass through. Another reason to avoid paper-backed solid vinyl wallpaper.

Note: This issue was with mildew. Mildew is not nearly as dangerous as mold. Still, the homeowner took the contractor’s advice and had the drywall completely removed and replaced.

Killing Mildew

November 2, 2017

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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.

Mildew Found Behind Wallpaper

September 20, 2017

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I removed a strip of paper-backed solid vinyl wallpaper from the wall over a shower in a room used by two teenagers.  The type of paper (one of my least favorites), the humidity from the hot and heavy shower usage, the  lack of primer used by the previous installer, and an exterior wall that most likely had some moisture problems, all added up to a recipe for mildew.

I used bleach and then another mold / mildew product to kill and remove the mildew, then went over it with an oil-based stain-blocking sealer called KILZ.

Over the KILZ, I added a coat of wallpaper primer.  The two primers that I use most are the large cans in the last photo, and they each are used for different circumstances.

 

Wallpaper Coming Loose – Bad News for the Homeowner

July 25, 2017

I was called to do some repairs today, where the wallpaper I had put up two or three years ago was coming loose at the seams. There was one seam a few feet away from the corner involved, and then also the edge of the wallpaper that fell in that corner.

I reglued the loose seam, and then moved to the corner strip. Before fixing something, I like to understand what went wrong to cause the problem. If you know the underlying cause, you have a better chance of fixing it, and you also have the knowledge to prevent it from happening in the future.

But I could not figure out why this paper was not sticking to the wall. After a little investigating, I discovered … that there was a layer of black powdery mold behind the wallpaper.

After more investigating (which involved pulling the entire strip off the wall), we discovered that there was some kind of water leak, probably from the roof or the exterior wall, that was allowing moisture into the wall. Moisture is going to cause mold / mildew, but with the vinyl wallpaper on top of the wall, which won’t allow air to pass through, the situation is exasperated.

Needless to say, I ceased with the regluing. And needless to say, the poor homeowners have a larger situation on their hands, to find the source of the leak and get it sealed up, and the wall repaired.

Bad Walls – Water Damage, Mildew

April 9, 2016
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This is what happens when a window leaks and allows water to run into the wall – for years. The Sheetrock has disintegrated, mildew is growing, the surface has become uneven, and there is the potential for stains from water and mildew and rust, plus the potential for delamination of surfaces, because nothing will stick to that powdery mildew.