What is this Mildew/mold/algae????

[plainpainter 217]

This stuff is really pissing me off!!!!! This is the stuff that caused me to strip this front deck a month ago. I couldn't get it off once it set in last time - it grew right into the finish. As you can see, I can wipe it off with my fingertips at this point - I've never heard of being able to do that with mildew?

YouTube - 013.mp4

And it appears now the deck is drying off that once again some of the finish got wacked right off again. I could see plumes of oil as I was brushing it.

[Celeste 341]

Dan if you can wipe it with your fingers - it's topical. Mildew happens on ALL surfaces, you have to assume that it's going to come back on a problem area that is still primarily organic. Especially since it was wipeable, it certainly is not an indicator that the finish needs to be stripped, just that you have a deck that provides great mildew growth conditions. Or it could be dirt :)

Also it's my understanding that the "cides" that are present in stains are not a "continuously" functioning component - their primary job is to prevent invasion during the curing process (which when THOSE fail are the ones that mildew growth is NOT wipeable and the problem is indeed in the coating).

[plainpainter 217]

The finish may not be need to be stripped, but any effort to clean the stuff off strips off the finish. This 'mildew' was only on for like 2-3 days when the rains started.

Last time I let it sit for a month before attempting to take it off - and it didn't come off like normal mildew does. I had to use my typical house wash solution before it gets siphoned directly from the 5'er and brush it on. That wiped off the finish completely. And the 'mildew' is not to be seen on any adjacent latex painted surface.

Whatever this stuff is - it ain't normal mildew. I have always been able to take off most mildew from a stained deck with as little as two cups of household bleach per gallon with a few squirts of 'soap'. This stuff needs a full blown exorcism with 2-stepping which winds up removing the entire finish. I was lucky to catch it early this time around - but I can see the finish has been dulled from even the weak bleach solution I used yesterday.

[plainpainter 217]

As well - I am starting to think that A.C. is perhaps a perfect stain for a more arid/dry climate. I've noticed that on this latest recoat, 10 months after the initial staining - that even though the pigment was wiped off the surface, it still had oils in the wood. This sounds like a good thing, but what I noticed that even just one application of this maintenance coat just didn't cure like the original. It still had oily plumes in the standing rain water one month after application. And since this has been the driest summer on the books with burnt out lawns everywhere - it ain't a due to a lack of dry hot summer heat.

And I think this sort of lack of curing may be an attractant for spores to stick to more easily.

[acegot 14]

Since it still had sealer in the wood, the parafinic oil couldnt penetrate enough to get locked in by the drying oils. As for the dirt/mildew, try to keep it clean. Wet, brush lightly hose off every 3 weeks as non freezing temps exist.

Last winter was a bad one for dirt & mildew in my area. All 3 brands of sealer used were the blackest in areas I've seen in a while. Have to start selling annual maint. washes again.

Edited August 28, 2010 by acegot

[Beth n Rod 1,279]

We saw this last year which had significant rains all year long.

I also noticed that the deck in your video is surrounded by plants which can release pollen and end up in the stain before it sets up.

Taking that into consideration I conclude that the extended time to set up makes it (Armstrong) vulnerable.

We noticed a higher instance of mildew proliferating on decks where there were pine trees/bushes in proximity as well.

Armstrong takes up to 36 hours to set up as the drying and non-drying oils need time to separate with one penetrating while the other seeks to cure on the surface.

In order to stave this off we add M-1 mildewcide to give it some added protection. No more problems.

Rod!~

[Beth n Rod 1,279]

We have seen this kind of thing across the board with multiple products that are oil based. It's frustrating, because there used to be a number of very good choices out there. It's the VOC changes. We are seeing it here on the east coast in spades. We have a repeat client whose neighbor had very little mildew on her deck compared to our clients. The neighbor had an acrylic installed. Our client had an oil. Very typical.

Beth

[Jake Clark 17]

Dan,

You should give us a call. We have manufactured 100's of thousands of gallons and seen most everything. Never be tentative about going straight to the source.

Jake

1 209 541 6579 cell

[pdmcali 15]

Could it be algae washing off the roof?