Can I make bathroom ceiling mold go away?

March 16, 2008 4:15 PM

The previous owners of my house obviously painted the bathroom ceiling with the wrong kind of paint. I now have extensive mold growth. Do I have any options, other than ripping the ceiling out and starting over?

Ideally, there'd be some sort of mold-killing sealant or barrier I could apply before repainting. Am I screwed?

posted by davebush to home & garden (12 comments total)

Spray with a diluted bleach solution. Seal with a product such as Kilz. Re-paint with a mold-resistant paint. Consider installing a bathroom exhaust fan if you don't already have one.
posted by Ostara at 4:17 PM on March 16 [2 favorites]

I made my own mold proof latex enamel with tea tree oil @ 1/2 Oz per quart.
posted by hortense at 4:36 PM on March 16

Came in to recommend Kilz, but Ostara beat me to it so I'll simply second it.

I love the idea of the tea tree oil. Does the oil lengthen the drying time?
posted by squasha at 5:09 PM on March 16

repaint with Kilz, then (if you want something other than Kilz white) paint over that with something else. I've done this with many bathrooms. I love Kilz.
posted by thomas144 at 5:20 PM on March 16

I would spray with bleach, and then use Zissner BIN primer. It is better than KILZ. Shellac base will seal much better than the enamel KILZ. I tried to seal a similar problem with KILZ, and 4 coats later it was still a problem. One coat of BIN shellac base and the problem was solved.

Overcoat with Sherwin Williams bathroom paint. It has some kind of agent to prevent this in the future.
posted by rocket_johnny at 7:11 PM on March 16

I painted the shower ceiling after repetitive bleach applications had taken a toll on the paint. The tea tree painted plaster board ceiling remained fungus free for the next six months that I lived in that house, the paint dried normally.
posted by hortense at 7:14 PM on March 16

If you really want to get rid of the problem, you'll need to rip the mold out.

Bleaching will kill the surface mold, but will not prevent the mold from growing. Sealant paints will contain the mold, but again, any moisture that gets in (through cracks, or from the other side of the ceiling) will cause the mold to spread.
posted by zippy at 8:15 PM on March 16

If you have the ability to do the work yourself, I'd just rip it out and replace it. Then you'll know for sure that it's gone. I'd use a some kind of drywall that has no paper. I believe the newest greenboard has none. Then finish it with something like plaster, rather than that chalky drywall compound that (trust me, I know) crumbles with moisture.

I painted a wooden bathroom vanity with a product from Rust Oleum called "painters touch". the finish has lasted 5 years now, without any softening, bubbling or stickiness from the moisture. Can't say the same for the special bathroom paint I used on the walls...
posted by gjc at 8:23 PM on March 16

I recommend cutting a small hole in the ceiling and putting a light up there to see if there is any mould on the other side of the drywall. If you haven't got mould going through the drywall or growing on the other side, then Ostara has the right solution. I would add that you should install one of those humidistats, too.
posted by acoutu at 8:48 PM on March 16

Putting greenboard on the ceiling is against code in many places. I believe it's because it's a vapor barrier, and any house insulation above it is also a vapor barrier, resulting in a space where moisture can get trapped (and cause more mold).
posted by ShooBoo at 10:50 PM on March 16

The previous owners of my house obviously painted the bathroom ceiling with the wrong kind of paint.

Not really. There are special anti-mold paints, but what the problem is here is moisture causing mold growth. You must fix this, or even an anti-mold paint won't be very effective.

Make sure that your bathroom ventilation fan is working and ventilating properly. (In some cheap construction, they actually vent it right into the attic.) If it doesn't have a timer, install one (easy $5-or-so replacement for the switch ... uh, turn off the power first), so it will run for 10-15 minutes after the shower has been used.

Check your drain, too, in case it's a slow one leaving shower water to stand too long. Check for any leaky pipes inside the wall. Look for ways that water could be splashing or draining out of the tub enclosure into a carpet or floor that takes a long time to dry.
posted by dhartung at 11:18 PM on March 16

Can you add a tag with the American spelling "mold"-- I couldn't find this because of the weird (to me) spelling. Thanks.
posted by nax at 8:13 AM on March 25