Paint and mildew
It’s time repaint the garage interior. We’re located on Cape Cod and the summers can be very hot and humid (like right now). So my north-facing, cool garage developed some mildew a few years back. We stopped the mildew a few years ago by finally putting a dehumidifier in the garage in the summers. That worked quite well but I still have the old mildew stains on the walls.
My question is what’s the best way to clean up and prepare the walls prior to painting them? I plan to use a flat latex interior paint, unless that proves to be a bad idea for some reason.
Thanks in advance for any advice you all may have.
“And those who were seen dancing were thought to be insane by those who could not hear the music.” Friedrich Nietzche
trisodium phosphate, bleach, and warm water. Use a primer and topcoat that has a mildewcide (add one if it isn't already in there).
Ah ha, thanks! Found this about the trisodium phosphate:
"It can also be found as a food additive; it is used as an acidity regulator (buffering agent), emulsifier, thickening agent, nutrition enlargement agent and sequestrant (metal-chelating agent). In these uses, all sodium phosphates may be collectively referred to as sodium phosphate, or by E number E339. The same is true when sold as an enema, working as a laxative to treat constipation."
I guess I can take of my problem and DW's at the same time... ;-)"And those who were seen dancing were thought to be insane by those who could not hear the music." Friedrich Nietzche
If the mildew is extensive, I would consider replacing the wallboard. What is on the surface may be more extensive in the wall cavity. Are you sure its the humidity and not a leak?
Also, use a semi-gloss paint instead of flat. Semi-gloss works better for wet areas.
Edited 7/20/2008 3:50 pm ET by arcflash
Thanks, arcflash. I'm sure it's humity and not a leak. I didn't give all of the info to keep it short but it involves retrofit central air with the air handler hung from the garage ceiling.
So I won't replace the wallboard for now. I'm sure the wall cavities are fine because I used a polyethelene vapor barrier and Tyvek on the outside. (Note: I'm just joking, folks, and don't want to start a vapor barrier war... ;-)
"And those who were seen dancing were thought to be insane by those who could not hear the music." Friedrich Nietzche
Edited 7/21/2008 6:55 am ET by Crash
Thanks for all of the input, everyone. I'll go to the paint store in town and load up on the good stuff. I hadn't thought about exterior paint but that makes sense.
For the TSP advocates, do you mix the TSP in with the bleach solution or is that a separate step? What is the recommended ratio, or will it say on the box?
Thanks again."And those who were seen dancing were thought to be insane by those who could not hear the music." Friedrich Nietzche
I mix the TSP, bleach and warm water all together. I never measure, but it's probably about a cup of TSP and and a cup or two of bleach per gallon. It's a good idea to rinse with clean water aftwerwards.
I agree with the TSP/bleach suggestion, but I would first try something milder like laundry or dish detergent. I've even had good results with dishwashing detergent. If that doesn't work, there's no harm done.
If the stains don't wash off, consider an oil primer to keep them from bleeding through. And for the topcoat, I wouldn't use a flat interior paint. Choose a paint with a little sheen so it can be cleaned more easily. Interior paint is probably fine, but an exterior paint might hold up a little better in a garage.
benjamin moore regal or aura. Latex is fine... just have to use the right product.
Why the recommendation on the B-M Aura? It's a good product, but I think all of its advantages would be relevant to interior painting and not a garage.
And besides, it's kind of pricey.
different resins. it dries thicker. holds pigment very well well. they make it for exterior also... wont have a mildew problem.
I'm not familiar with Aura exterior paints. I just checked out the B-M website and they only show Aura as an interior paint. Even so, I'm sure it would work fine.
Someone makes a bathroom specfic paint that is mildew resistant.Ah, here it is. Zinser Perma-White. They have both interior and exterior version.http://www.zinsser.com/subcat.asp?CategoryID=4.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Perma-White is pretty good paint and supposedly guranteed against mildew for something like five years, but it can be a pain to work with--at least the tinted version. I recommend not trying to cover with one coat (or even two), but to put on light (thin) coats and don't worry that they aren't covering. If you try to apply it thick, it will seem to be okay, but when you look at the wall you painted before the one you are painting now, you'll see runs. It doesn't seem to "wet" the surface either. Anyway, I found that two or three very thin coats is the answer.
I just checked out the B-M website and they only show Aura as an interior paint.
I posted that on July 20. Today (21 days later), the Benjamin Moore website does indeed show an exterior version of their Aura paint.
Maybe I need a source of information that's more up-to-date this this old-fashioned thing we call the internet.
A website called green building discuss the mold removal at depth. They recommend Kilz primer that prevents mold from returning. It is labelled as such. They recommend Zinsser finish paint. Both have proven records. TSP need to be rinsed, I believe. Any detergent will have to be rinsed really well. Detergent left over will make the paint fail, that is, loose adhesion. You could just wipe with solution of(1:16) bleach to water. Stain will have to be repainted. Nothing will remove the stain from the drywall. I would treat the mildew the same way. I think you can also buy additive for regular paint that makes it resist mildew. Try a regular paint store. Homedepot sometimes is missing such additives. Hope this helps.
Good question - simple answers.
"My question is what's the best way to clean up and prepare the walls prior to painting them?"
- Do not use bleach - use a chemical/cleaning regimen specifically targeted for mildew
"I plan to use a flat latex interior paint, unless that proves to be a bad idea for some reason."
It is a bad idea. Use an EXTERIOR paint, preferably satin or semigloss. The exterior paint may look a little ropier, but it can stand the temperature/moisture extremes of an unconditioned space much better.
I'm a big believer in primer, so with the prior mildew problem I would probably prime with a good primer (Fresh Start for example) with mildewcide in it (despite the fact that they've taken all the good chemicals out of it)
"Do not use bleach - use a chemical/cleaning regimen specifically targeted for mildew"I'm curious - what would that be, bny name?and why not clorox?
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I'll chime in--what I read just recently is that bleach bleaches the color out of the mildew and spores, but does not kill them (only makes them less apparent). It also doesn't penetrate very well (more of a problem when removing mildew from wood). Most places now recommend scrubbing well with detergent, rinsing and letting it dry, then painting. Depending on how bad the mildew is, removal of the drywall and replacement with the new paperless stuff may be the best bet.
Actually, chlorine bleach is an excellent sanitizer and will kill mold, but I agree with you for the most part. Bleach doesn't work well on porous materials like wood and paper.
On hard surfaces, just scrubbing to remove the mold is probably sufficient and bleach isn't really necessary, because a thorough cleaning gets rid of the mold and the spores.
I'd think that you could use bleach to kill mold on unpainted drywall, but you'd need to saturate the paper to be effective. You'd probably do enough damage to the drywall that replacement would be easier (and more certain), especially on an area of much size.
Sorry ... yes you can use bleach if you mix it right - http://www.sherwin-williams.com/do_it_yourself/painting_techniques/painting_problem_solver/dirt/Mildew/ but many people mix it too strong, don't rinse well enough and then wonder why the paint doesn't stick.
scrub with TSP, then with some clorox in the water, then rinse and dry.
Add mildewcide to th e paint, or buy a paint with a mildewcide in it.
Flat interior latex not usually washable. I would want a washable paint for this location.. It is usually a tougher paint and would be more resistant to moisture problems in general
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