white powder on deck

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  #1  
Old 07-26-03, 10:24 PM
Bonny
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white powder on deck

I have just completed multi-level deck using pressure treated 5/4 decking fastened underneath with "deckster". It has been finished with redwood tone BioWash "Natural Deck Oil". This is formulated for wet pressure treated wood and worked great. However, for some reason I get a thin film of fine white powder on the deck every day. This is rather irksome as it spoils the nice clean finish that I worked so hard on. I think it is an airborn deposit of some kind as the deck remains clean under the railing structures. I have to wet down the deck and give it a light scrub with a soogee brush to clean it off - but there it is again the next day. I am thinking that it could be pollen or something and that it is probably on everybodys' deck- they just don't see it because none of my neighbours' decks are finished. The area I live in is on the edge of a small town a couple of blocks from the shore of a large fresh water body. There is no industry around- no smoke stacks. There are flower beds and very large maple trees in the garden. Any ideas? Maybe I'm just too fussy!
 
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Old 07-27-03, 09:20 PM
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I don't think the problem is airborn -- I've got a sneaking hunch it is the PT boards just trying to dry out.

Maybe fewalt will come in here and have a better answer for you. Under the railing structures -- simply not getting as much sunlite.
 
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Old 07-28-03, 09:23 PM
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Hi Bonny,

I can't think of any white powdery coating that will come from the PT lumber alone. Some cleaners, oxalic for example, will sometimes leave a white blotchy crystalization if not rinsed thoroughly.
I don't know where you are located or what may possibly be 'blloming' now, but I do think it may be an airborn pollen.
Have you also found the powder on deck furniture, gas grill, or anything else outside? How about on a vehicle parked outside?
My black truck sometimes appears yellow from pine and poplar pollen.

fred
 
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Old 07-28-03, 10:37 PM
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No Bonny, you are not being too fussy.

If this is something that is indeed airborne, it should be on other surfaces besides you deck, like Fred said. His black truck shows the pollen from the pine &/or poplar pollen. My brown spa cover shows the yellow/green from the ash trees.

Or it may be that this white powder is due to some reaction between the chemicals used to PT the wood and the BioWash "Natural Deck Oil".

Tell me it's on things other than JUST the deck, and I'll figure it's probably a pollen. Tell me it's ONLY on the deck, and I'll figure it's the reaction thing.

I don't KNOW for sure -- I can't see it.
 
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Old 07-29-03, 06:55 AM
Bonny
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Thank you Lefty, thank you Fred.

Here are a few answers to your questioning hints. (Your hints have made me realize that this stuff has got to be airborne.) Yes, there are deposits on the BBQ cover and other things. There is a 23' x 14' fixed louvered overhead structure oriented toward the south that keeps the fallout off the privacy wall and upper structures. This follows the roof slope and has an average height of 12'. When it rains, more white stuff does drip down onto the deck. I have an irrigation system built into the overhead to keep the flowers in the pots alive - they are too high to water. But I don't think that this is causing a problem. There is always something blooming around here - except in Winter! I live in SW Ontario on the shore of Georgian Bay - an arm of Lake Huron. I guess I will look on the bright side - at least it is not soot from a smoke stack. Actually, since I sent my first post the white stuff seems to have tappered off.
I have to say that I am pretty sure that the Biowash Deck Oil is not contributing to this. I prepared the PT wood with the prescribed cleanser and a deglazer. There is no way it wasn't rinsed enough. I can't say enough about this product. Some people who see the deck can't believe its PT. It soaks into the wood without completely sealing it, so the wood is not prevented from drying out. When it wears out it doesn't chip off it just sort of evaporates. This Spring I recoated the first level (completed last year). It had worn away in spots. All I did was give it a wash, deglaze to set the surface Ph, put a first coat on the bare spots, then put a second coat on the whole deck. This was all done in one day and the spots that were bare were indistinguishable when finished. I do think though that a consequence of these qualities is that it probably has to be recoated more often than wood treated with a product that sets up with a tougher surface barrier. But it is comparatively very easy to recoat. I can see that I am going to have to give the deck another coat before the end of the season because of all the scrubbing I have done!

Thanks again guys.

Bonny
 
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Old 07-29-03, 05:44 PM
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Airborne. Probably the only solution is to hose it off regularly and ENJOY the deck and all of the flowers!!
 
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