Quick composite cleaning

We’ve been doing composite decks about 3 years and althought our process is efficient it just may not be quick enough. We went out last season and looked at 88 small decks (no large than 6x10 half of them being second story) which they decided to push off to this season. I cant imagine the time we would be in it for 88 decks with our process so im reaching out to you guys for advice. How would you do it? Roof pump and a low % house mix? Im hesitant to do something like this, we once had a guy over shoot a roof and had some land on a deck behind a house and leave some spots but we were able to blend them. Since these lower level decks are covered, they seem to be growing a decent bit of algae and what looks like to be dark leopard print spots on them.

Whats the process you are using now?

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DS mix, soft brush, dwell, light pressure rinse. Reapply if necessary.

maybe i should be not downstreaming it as im running a 10:1 injector so its a darastic cut from our already 2:5 house mix

I just an xjet and git it with 4-6% and they clean right up! never had to scrub one. sometimes i have had to use 800-900 psi in a wide spray to knock white stains.

I dont disagree. However, with this job xjet would be a pain for sure. Id have to have a huge line on the xjet and carry a bucket around to every seperate deck. Itd be great to have something truck mounted and only pull hose. 3 man crew, one rinsing plants, one presoaking and rinsing and the other applying chem!

add a 12 volt system and make batches of deck wash.


well that was my question. Maybe my mix isnt correct due to the fact that im down streaming and its getting cut to much, I would like to know others cuts. As stated in the post, we had a guy over shoot a roof and get some on a blue composite decking at one point. It left extremely light blotches all over the decking which we were able to blend but added a lot of time to the job. I just wanted some advice on either a stronger downstream, or a weaker mix not being down streamed.

You likely won’t get a strong enough mix DS-ing. You should do test spots and figure out what mix works best for you. We likely live in different areas and have different types of algae and stains. take a pump up sprayer and make a batch of 3% mix. Try it out… then try 6% and see if it works. Find out what mix works without using more than necessary.

4% SH hitting the surface mixed with a non caustic degreaser. I use power solve from hydro chem.

Spray, dwell 15 minutes…respray if really dirty and rinse. I never use pressure on them, can literally rinse with garden hose,

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Ill give it a shot, granted the mix her over shot was practically a 50/50 trying to kill as much moss as we could to remove before we left. Im not great with the percentage. but i would assume to get 3% with 12.5% SH you need 1:4 mix or something like that. Im not mathematician.

Biggest thing to look at is if it’s gen 1 or gen 2. Gen 1 set expectations, charge more because you might need 1000 psi on some decks. Gen 2 is literally the easiest thing to clean. Pictures you posted we would be at $70 per deck.


How can i tell the difference between gen 1 and gen 2? These buildings are older so i can only assume gen 1. Every composite deck we’ve done ive always use the same process

Texture. Gen 2 is fully encapsulated. It has a sheen to it when clean, just like vinyl siding. Gen 1 has a rougher texture and duller look. It is porous, and prone to wood related staining like tannin stains.

Gen 2 can be cleaned with a moderately strong down-streamed housewash.

If it turns out to be gen 1, my approach would be with an xjet. Calculate how much straight SH & soap solution is required for one deck, using the proper proportioning tips, and then select a small container to carry that much solution. Refill between decks.

I would carry the container in one hand and spray with the other. Use a 3 foot hose for the xjet.

You can put a ball valve before your gun to choke the flow and lower the pressure from the xjet. It will help with runoff and overspray issues.

As mentioned already, setting proper expectations is important with cleaning gen 1

Gen 1 can change colors with a strong mix. If it’s gen 1 I would walk. I’ve cleaned enough if them to know its a crap shoot. Most gen 1 have been slaughtered with pressure from previous contactors and are very porous. Any other type of composite i use my house mix and rinse with jrod. If its really bad and some what beat up I use my 12 volt with a weak mix and rinse the same. A white pressure tip can remove the protective layer of newer composite. Never use pressure. I’ve used a deck brush plenty of times on decks. It only takes a min to scrub a large area that might not be reacting well to your mix.

im going to take another ride to the site tomorrow and share some more pictures before anything. Hopefully with more detailed pictures you guys can confirm gen 1/gen 2 and help me out as far as mixture.


Gen 1 cardboard, Gen 2 plastic.

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anybody know when gen 1 was discontinued?

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You used a deck brush on a deck? What a novel idea.:grin:

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