Hardi plank oxidation/paint issue

Figured since I am trapped in the truck, waiting on this thunder and hail storm to pass over, had a question to verify what I have studied here.

I have this house as shown in the pictures. It’s hardi plank and what I believe is oxidation. I know what I should be doing is walking away, but it’s slow and if I get this job done there is a whole subdivision with this problem that will let me upgrade to my pro machine.

The original paint was a dark green, now the East and South are starting to turn that tan color. I mixed up some 1% in my steady bottle, then hit it with my soft brush and it rinsed away clean. Letting my mix dwell on it then rinsing ate into it the smallest amount, basically doing nothing.

There are some spots under the exhaust vents where the paint is peeling away from the board, and as I watch the train the parts with the color change is where the rain is not hitting the siding.

I explained to the homeowner what the issue is, that there’s no guarantee I can commit match the whole house, and they are going to have to repaint. 12 year old home. She still wants to go ahead so I am taking the opportunity to learn just how much I won’t want to do this in the future.

At this point my plan was this:

  1. No pre wet, DS my HW mix onto a section at a time (.7 to 1%)
  2. Let dwell for a couple minutes (no surfactant), them hit it with my brush.
  3. Rinse off under low pressure and carry on.

Alternate plan was just make my mix up (1%) and put it on using the brush. Wasn’t sure which will work faster/better.

Anything else I am missing? Thanks in advance for everyone. This last week spent going blind reading my phone had really helped me spot these issues, educate the customer, and secure the jobs helping to move me more into the personal role I want to be in.

If there was a poster with the term “walk away” this would be the photo…

Dont even entertain one more conversation.

Your walking into a waste of time, money, energy, and possible liabilities.


Don’t worry, guys! He just posted this as a joke to rile folks up. There’s NO WAY he is seriously considering taking on this job. He’s just having a little fun with us all.

There, I covered for you. Now you can say you were just kidding and everybody will totally believe it.


That’s what my instincts were telling me, but I just wanted to make sure. Out of the 40 houses in this neighborhood I walked, at least half are showing this issue, not to this extreme but I can tell the order these houses were built in.
Dollar signs were in my eyes clouding my judgement, doing even 5 of them would have got me back out of rental equip.
Oh well, live to fight another day.
Follow up question: this person has never had this house professionally washed, just garden hose. I know the main problem is the paint, but if this house had been maintained, what are the chances that this effect would have been minimized? Thinking of possible marketing avenue for the other houses not showing this issue here.

Lol, thanks Displaced. But no cover will save me as I just rolled up and was going to tie into it. Thankfully the washing gods sent that storm my way to slow me down and do the right thing and post here.
I mainly stick to vinyl and stucco as that’s pretty common around here. Have stayed away from hardi from everything I have been reading, but wanted to add another “type” to my list. Will find some that aren’t so far gone lol.
You guys are amazing!

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Please post an after Summary on how long it took you with pictures of after , how much you charge

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I would give them an estimate, a strong one with attached pics and disclaimer that you are just cleaning in preparation for painting, some of the existing paint may run off and not to include any scraping necessary. Take even more before pics to cover yourself and go for it. I’d just DS a normal hw mix on it, that will take care of the algae stains. Collect check. Way I look at it, no matter what you do, it can’t look any worse.


Thanks Racer. I did give this as an option, and let her know it moved beyond cleaning.
Hopefully she takes me up on the pre-paint clean.
Good learning day.

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Had a landlord I did 6 houses for this spring,her husband just died and she wanted to sell the houses.She wanted me to clean the gutters,soffit,and fascia,but not touch the siding.I wished her luck and a nice day.Called me the next day and agreed to wash the entire house on each property.Signed a contract stating that the aluminum siding was badly oxidized and would show bare metal when finished.When I say bad ,you could take a micro fiber cloth and rub to bare metal. Normally don’t wash these type of properties but her realtor told her that anything would be an improvement…Kind of typical slum lord properties but you take what you can get(ok ,I take what I can get);albeit with LOTS of before and afters and a signed contract stating that I advised against washing unless for paint prep.

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Looks like the subdivision i just washed. Those are not oxidation marks. Its where i did test spots.


Obviously the house needs a paint job. If there are that many homes in the same neighborhood with the same issue, why not partner with a reputable painter and offer a single price for a prep clean & paint job? You win, the painter wins, the homeowner gets what they’re after. Just make sure the painter has experience with Hardie and the homeowner understands that the paint job won’t last forever.

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