Dark green siding

Bid a job to day with dark green siding. I’ve read in here it can be a pain sometimes. This color green has hidden the years of algae and the homeowner states he hasn’t had it washed in 11 years. What steps would you guys take ? I explained to him the possibility of noticeable “clean” marks after I was and plan on doing a section and letting it dry to see how it turns out before proceeding ok the whole house. If I’m careful with my pressure and keep my distance, even if there is oxidation I shouldn’t disturb it, correct ? I know some of you walk away in certain colors, but this dark green siding is popping up all over the place in my area so I’d like to be able to not turn all of them down when I get a request to do one. Thanks for all your help.

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11 years isn’t “popping” up now


Sometimes you have to wash the green to get the green amirite?

So In no circumstances would you wash it ?

Agreed to the 11 years thing, however I live in an area that was pretty rural until the last 2-3 years of huge growth with subdivisions etc. and it seems the dark green is a common choice of siding in the newer subdivisions so I’m sure this will be one of many requests to wash dark green homes.

I don’t wash blue, green brown or red homes. Not with the risk.


Well, hopefully he calls back saying I was too high then. If he wants on the schedule then I’m not sure what to do, I’ve read a lot of posts from you and you seem light years ahead of me on all this so I’m sure if you don’t do them then you have good reasons and bad experiences for having that tilt for your business.

Hi Innocent. I have seen this mentioned before and just got my first house wash which is a light blue vinyl. Is it the darker of the colors you are referring to or is it any shade of these colors?

One more question. sorry. my buddy who is her landscaper got me the job and tells me there’s is basically no algae growth. not bad at all he said. Is it possible with just H20 and elemonator would do the job ? basically trying to mitigate the potential SH liability if possible. I understand the rinsing and rinsing concept but a little worried on my first job I will end up posting the same thing as the OP!

BTW, thank you and all the other vets for all your insight on this forum.

So the owner just messaged me back and wants to schedule a day to do it. How would you go about turning him down or does anyone have a method that helps get good results on a dark green home. Haven’t received any tips so far so I’m assuming everyone else agrees with innocent bystander

If you want to turn him down just be honest. Tell him you’ve spoken to other contractors and explain the risks involved. No need to try and make excuses to bail. If you decide to go ahead and do it go with as weak of a mix as possible and only use it on the sides that have algae. Otherwise just use a little surfactant. Definitely pre-wet, no longer of a dwell than needed, lightly mist from a ways back, and rinse, rinse, rinse. It’s a crap shoot though. You might wash twenty dark houses in a row and not have one single problem. Then all of a sudden, boom. If you take the chance I’d do a test spot and let it dry before proceeding.


If it’s dirty and hasn’t been cleaned in 11 years a light mix will keep you out there all day but a heavy mix could contribute to making the oxidation more pronounced. Tell him that some green houses can look blotchy, dry uneven or even look wet for days in certain areas. Put it on your written estimate so it’s in writing. Let him say wash it anyway.

A few things:

You never mentioned what kind of green siding. Green vinyl? Green Hardi? Wood that’s been painted?

The mention of “clean marks” makes me think you’re cleaning this thing using pressure vs cleaning with chems. What is your cleaning process?

Many of us routinely clean siding colors that others stay away from. You have to a) identify the material, b) test your mix, and c) as @marinegrunt said, lots of pre-wetting, misting, and rinsing.

It is green vinyl. I’m not using High pressure, 5.5gpm down stream 12.5 SH W/ elemonator with j rod. I ended up waking away from it, with the size of the home (3,800 sq ft) and the fact that it hasn’t been cleaned in 11 years I didn’t feel comfortable doing it. In the future if I get a small dark green home with normal 1-2 year organic growth I MAY give it a shot but at this point I felt it was a better option just to walk.


Smart move.

Thanks. Appreciate the advice.