What to do with black spots on Composit Decking...

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Posted by: from Tahsis
8/13/2012 at 5:48:12 PM

Our back porch composit decking is full of small black spots we have tried power washing only gets rid of a few small ones.

Is there anything else we can try?

We have to build another deck out front of our house with stairs and not sure if we want it to look like the back.

Can anyone help us please.

Thank you


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Date/Time8/13/2012 at 6:16:51 PM

It's likely mold. Try spraying with a half aqnd half solution of bleach and water. Wash off the next day.

Theres probably to much shade over the porch.

Can you trim the trees back a little?


Andrew Parker

Par-Tek Construction Services

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Date/Time8/13/2012 at 6:27:03 PM

Hi Birtie:

Andrew is right with his answer. However, I would be inclined to get in contact with your sales outlet to see what the manufacturer recommends. Your type of decking may have a warranty on it from the manufacturer, and you don't want to void it.

Knowing the weather conditions where you live, it is most likely mould that is in the crevises of the planking. However, this product is in use on the west coast and they must have had the same experience.

If you try the bleach solution, make sure that it is diluted. Once the black is removed as much as possible, use a bit of bleach in a wash solution at least once a month. This problem will reoccur especially if the porch is in the shade.

The product that you are using is great. However, like every other type of decking, walkway, and siding mould spores will deposit themselves, and start to germinate.

It may take two or three applications to eradicate the problem. Then regular attention will control it.


Meadowood Homes

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David from Chetco Homes in Fort Erie
Date/Time8/13/2012 at 7:38:26 PM

The answer that you are getting are good But i would try CRL you can get it a Canadian Tire.

I would test it first on a small spot. But I agree the first ting I would do is contact the manufacture.

Good Luck


Chetco Homes

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