Today didn’t go as planned, do I need a different chemical?

So I had a job today it was a house in a new development condo complex. The front of the house was hardie plank and the rest of the house was vinyl. They called me out because the house was really dusty and dirty from all the construction that’s been going on for years. So I did
The vinyl like normal no issues but when I got to the hardie plank I washed it and it didn’t come clean. It’s not organic it looks like a rusty color mud/ dirt

So I re applied and and then used a scrub brush to agate. Still nothing, I re applied and scrubbed harder, nothing, I then upped the pressure two times and still nothing. It seemed like it lightened up a bit but not much. I’ll post some pics down below but is there’s different process or another chemical I can try? Unfortunately ( shame on me) I didn’t have anything else on the truck. I don’t know how long it’s been like this all the condos have this same reddish staining on them.



It’d probably come off with OneRestore or F9. But I’d be nervous using that stuff on hardiboard. Test small to start with.

My gut says that’s mildew streaks from the runoff around the windows and that a basic house wash mix should clean it up just fine. Test spots would reveal all.

It’s orange / red in color? Can that be mildew?, And even though I took a picture of the streaks under the windows the whole front of the house is covered in this red and orange stuff all the trim all the siding. which I assumed was dirt. If it is mildew I’m surprised all the washing, scrubbing and even higher pressure wouldn’t have removed any of it. All of the houses on that street have the same orange red staining.

Hmm interesting. It doesn’t look orange on my phone at all. Just for S’s and G’s dab a spot with some SH and see what happens.

It crossed my mind when I was there to do a test spot but I didn’t, Ya the pictures aren’t that great it was really cloudy today but it’s a red / orange color it’s very noticeable on the white trim and on the siding in person.

Are you located near any red clay?

Not really I’m located in CT indicated by the red dot

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Anyone have any other ideas what I can try? Ide like to find something to help this customer out. Thanks in advance

Get on Facebook, join the F9 group and post that picture.

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If you really wanna go for it, start here ^^

Muriatic Acid is my go to for orange stains. Painted surfaces make me nervous tho especially Hardie. It will brighten or slightly lighten some paint so do a test spot if you try it. Rust stains I usually start with a 1:1 ratio and bump it stronger if needed. Light orange or dirt staining I’ll start with a 1:8 mix and brush it on and scrub it off after a few minutes but you better be testing 1st on painted surfaces

I have stains like that under windows on vinyl homes that came off easy with aluminum brightener, but never tried hardie board. I’ve used it on painted trim though for rust stains and never had an issue with paint. So basically I think the consensus is some sort of acid and do a small test spot.

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i suspect it’s from the wood unpainted side like it bled out whatever coloring it has. it certainly can be years of dirt.

All the condos on that street have it. They all swear it’s from all the construction they have been doing / still are doing. It’s all over the house the front is covered. I thought it was just dirt originally but I washed it, scrubbed it, and kept increasing pressure and nothing changed. So now idk what it is.

you could always try a mild degreaser

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You don’t indicate what chemical you tried.

If you were called out to address construction dust and dirt but you just bleached it, perhaps instead try a cleaner/degreaser such as sodium metasilicate (Krud Kutter, etc). But if it’s some sort of rust bleed, then I agree with the acid recommendations. Either way, try a sample area and don’t let these things dry on glass or metal.

I continue to be unimpressed with everything about Hardi board…