Mildew question: We build many screen porches. Occasionally we will leave the yellow pine roof members unfinished. While we have not had mildew problems before, one project is growing a crop under the overhangs, where it never gets directly wet. Is the best thing to pressure wash with bleach? Something else? Can we do something to prevent a recurrence? Can we leave it unfinished? If we do need to put a stain or a sealer on it, what would work best?
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You may not even need a pressure washer. A bleach solution followed by a garden hose may get the mildew........this time.
You need to figure out why you're getting mildew in the first place. Even if the overhangs aren't getting wet, there must be a source of moist air nearby. That source needs to be reduced or eliminated.
JJ,
It could very well be mildew, but dust collects on the surface of exteriors and can look just like it. Either way I usually use a siding brush, and a solution of around 20% bleach and some clothing detergent. I use this on decks as well.
Put solution on wall and scrub. Wait 15 minutes and keep lightly wet if its drying fast, then rinse thoroughly with hose.
I wouldnt suggest a power washer, that can add to the problem.
Wear safety glasses and gloves and if overhead, expect that it will run down your arms.
-zen
Thank-you O zendo. I will give it a try. I do think it is mildew and not just dirt
Got it, no pressure washer. Maybe I should move the porch from Georgia to Arizona. Short of that, any way to prevent a recurrence, this time or on a future porch?
Edited 8/9/2005 6:03 pm ET by JJ
Gawja, huh? Birthplace of humidity, right? - lol
I'm betting that this overhang is on the north side of the house - and away from the prevailing wind direction. Are there any largish plants (shrubs or bushes) directly below the problem area? Are there any tree branches close to the roof near the area? If you have either (or both), some pruning may help by opening things up and improving circulation so moist air doesn't accumulate.
Otherwise, you're probably looking at a sealer with an algicide in it - and periodic maintenance.
If you seriously consider the AZ option, be aware that it takes at least a week just to drive across TX - lol.
Even the fish sweat 'round here. And this has been the wettest July since the Cherokee moved to OK.
Thanks for your help
Any time JJ. Hope I helped a little. Yeah, I know about humidity..........I grew up near St Louis. Been in CA since the early 70's and don't miss it at all. Today, the weatherman said that there's some tropical air moving up the Sierra Nevada mountains carrying a lot of moisture (thunder boomers in Vegas). I believe him. It was positively sticky outside today...............RH must have been at least 50% - lol.
Happens all the time up here in the Pacific - the We(s)t Coast. Generally it's the ambient air moisture, sometimes the lumber isn't too dry and integral moisture comes out (and w/out drying with wind, it'll remain stagnant). The worst it could be is that there is a source behind - improperly vented roofspace, ditto exhaust duct, no vapour barrier, etc.
ciao for niao
To those who know - this may be obvious. To those who don't - I hope I've helped.
Thanks piko. I think it is the ambient air here, tooJJ
JJ,
There are packets of mildewicide you can add to paint, I would figure you could put it in any finish you use if the product you have doesnt have a retarder in it.
-zen
Treat it with Boracare?
BORACARE? I THOUGHT THAT WAS FOR TERMITES, CARPENTER ANTS, ETC. WILL IT KILL MILDEW?
It takes care of fungi as well, molds, mildew, rot, etc.
That's why people treat their log homes with it. If it's not in direct contact with running water, it should stay in the would, so unlike log homes, you shouldn't need to re-treat it every couple of years.