Mold on Ceiling on Flat Paint

Question

Not sure what exactly the line of thought was here, but my bathroom walls were painted with flat paint. While there is a fan in the bathroom, I'm not exactly sure how well its working, as it seems that the moisture from taking showers is not able to escape properly. This has led to both mold and the paint cracking (surprise, surprise):

It's pretty rampant throughout the bathroom:

I'm not exactly sure what to do about it, since it seems to be a recurring problem. After we clean it, it just reappears a few months down the line.

Now that the paint's cracking, I'm debating what to do. I was thinking of just cleaning off the mold with bleach/anti-mold treatment, then just painting over the entire ceiling with high-gloss white paint, but now that the paint is cracking, I'm really not sure what to do. I don't want this to turn into a huge project, but I'd like to solve the problem once and for all if possible. What should I do?

Answer 1

Make sure everyone using the bathroom uses the fan.

The exhaust fan has some how moved. Inspect it to see why and check to see if there are any issues with the duct. Also make sure it is sized appropriately for your space. See this guide on bathroom exhaust fan sizing from the Home Ventilating Institute. You may want to consider a larger fan (or better fan) if it's not working.

They have a number of different options for fan switches that have timers that keep the fan running even after the lights have been turned off. I've even seen one with a humidity sensor that automatically turns the fan on and off. Consider getting one of those.

You're going to want to repaint. In a bathroom that means you have to thoroughly clean the walls whether you have mold or not. Too much stuff accumulates on walls in bathrooms to get good adhesion without cleaning. That might be why you're seeing peeling more so than from the steam. Scrape off any peeling paint and sand the edges to feather them and repair any large dips or gouges.

Paint with a high quality paint meant for bathrooms. Most good paint these days seem to have mold inhibitors in them. You don't need to go with a higher sheen paint. In the past I've used Zinsser Perma-White, which I believe was one of the first paints with mold inhibitors. It is available in eggshell. I recently used Benjamin Moore's Aura Bath & Spa paint which is in their Matte finish. It's somewhere between flat and eggshell, maybe leaning more towards eggshell. Happy with both but really thrilled with how well the Aura went on and has been holding up.

Answer 2

Well you have three things to do:

1. Get a better fan.

2. Change location of fan closer to shower. I can see most of the mold is by shower and that means that the fan air flow isn't catching this. It is possible that a much better fan would allow you to keep the fan in current location.

3. But before you do those get rid of all mold in your bathroom, then use a mold resistant primer and paint on the entire bathroom.

Point #3 has been answered to death on this site. You need to get rid of all mold and get that bathroom dry for a few days before you do anything else to it. Your tiles probably aren't helping but retiling should be a last resort.

Answer 3

As it turns out, there is absolutely no ventilation in the bathroom whatsoever:

This is the fan. It simply pushes air downward into the bathroom. It is not connected to any ventilation channel whatsoever.

For others with this problem, examining your bathroom fan is definitely the first step.

Afterward, examine other options like scraping the paint, cleaning up and killing the mold, then repainting with mold-resistant paint.

Answer 4

There are a number of steps that should be taken here, but the ultimate goal is clearly to come up with a better ventilation system.

1. Remove the mold stricken areas. It's a pretty safe bet to cut 1 foot around them in each direction.

2. Sanitize the area around the remaining areas. Bleach is less than ideal - if you can get a spray bottle of Concrobium from Home Depot, that's your best bet.

3. Mold resistant primer/paint is definitely of value in a bathroom. Pick up a tin of Zinsser from Home Depot. You can just do one layer without primer and it can be mixed up to 2 parts Zinsser one part any other paint to create a nice tint. Makes for good pastel colors. This is a standard in the remediation industry.

4. Remove that fan - that's an atrocious set up. I'm glad that you seem to have come to terms with that already.

5a. The ideal bathroom fan pumps air out of the house. The second best is that it pumps air in to the same duct that your dryer uses, which then exits the house. The third best is that you create a system that allows the fan to suck air in to a dehumidifier in either an adjacent room or in the bathroom itself. One easy way to do this is to funnel the air through a dehumidifier in the attic. The common mistake is that the people often blow the humid air up in to the attic, creating another mold hotspot. You will have to create a shared switch system that turns on both the fan and the dehumidifier at the same time. You can then either let the water drip in to a drainage pipe that lets gravity take the water to a drain in your basement or bathroom. An alternative and more expensive full house system is described here: www.ultra-aire.com/images/pdfs/UA-XT150H_Spec.pdf

5b. It's a bit of an eyesore, but here's a cheap and effective fix if you don't want to go through the ordeal described in #5: http://www.amazon.com/Eva-dry-Edv-1100-Electric-Petite-Dehumidifier/dp/B000H0ZDD2

Best of luck!

Source: I'm a water damage specialist for a restoration company.