Cleaning Composite Decks

Old 05-02-10, 08:19 AM
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Wink Cleaning Composite Decks

I need to clean a 3 year old composite deck surface (TimberTech). No significant stains on it, just a fairly uniform medium level of mold and grime. There are a number of products one can purchase, but the couple I have looked at are expensive and require close monitoring when applying, apparently because of their strength. Can anyone suggest either a) a "household remedy" that they have found works well, or b) a product to purchase that does not have the above drawbacks. Thanks for your help!
Old 05-03-10, 05:04 AM
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Start with dish soap, water and a deck brush. Won't hurt the deck or the surounding landscape in any way and it's biodegradable. Rinse well.

If you need to get aggresive, try Simple Green or a similar cleaner. Be careful about using any strong bleach solution as that could cause the decking to fade and could damage the landscaping.
Old 05-03-10, 05:42 AM
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I'm not sure you can get around using bleach to remove mold/mildew but on a composite deck, I'd use a weaker solution [25% bleach 75% water] If dish soap isn't strong enough - try laundry detergent. It's always best to have the substrate wet before you apply any cleaning agent and always rinse it off before it can dry. I like to use an old broom to scrub with - it saves my back

If you use bleach you will need to protect the vegetation. This can be done by covering them up with plastic [make sure you don't cook them] or what I usually do is wet them down with water - before, during and after. The keeps the bleach diluted enough to prevent damage.
Old 05-03-10, 07:37 AM
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I've got a TimberTech deck that developed some mold last year (the third year it has been in place).

In early May of 2009, I tried a product from HD that I had used with great success (removed the mold without much scrubbing) on a TREX deck in our last house. It didn't work the same on this deck and I was told that HD had to change the chemicals because of EPA regulations.

I spent June and July expermenting with different combinations of soaps and chemicals and came up with two combinations of steps that have held up all through the winter. I used each combination on one-half of the deck so I could compare and both seem OK so far this spring.

Step 1 (Both combinations) At least once a week vacuum or blow off all leaves, needles, etc.

Step 2 (Both combinations) As necessary, general cleaning of dirt or grease with dish soap in water applied with a scrub brush.

Step 3 (Both combinations) I handle stains that don't come off with soap and water by light brushing with a wire brush. This will remove a little bit of the decking, but isn't noticable if you go with the grain effect.

Step 4 Mold (Option 1) I use a 25% solution of bleach in water and scrub it in. I let it sit for five minutes and then rinse it off while I scrub it again. There are three problems with this option: (1) it will harm your plants unless you protect them; (2) the bleach will fade the decking a bit so you need to work in sections and be consistent in how long you let the bleach sit and (3) the mold came back after about six weeks which meant I had to do this option every six weeks.

Step 4 Mold (Option 2) I bought an expensive product called Corte-Clean mixed according to the instructions, scrub brushed it on and let it dry in place (not according to the instructions). After a few days I rinsed the deck. This product didn't harm our plants, but does have a few problems: (1) expensive; (2) the deck faded a bit so you need to work in sections and be consistent in how long you let the stuff sit and (3) you have to mix the powder with hot water which can be difficult.

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