Help! Spots on Hardy Board!


Hey guys first post here. We are a small company out of Alabama that does a fair share of residential homes. Today we did a house that wasn’t bad at all just some mildew/mold on the porch ceiling that we used our normal house wash on. We use 1 1/2 gal of 10% SH to 2 gal of water with 3 ounces of elemonator. We have a 4 gpm machine that we soft wash with. The house looked great when we left but got a call back a few hours late for spots that almost looks like it’s bleached! We went back and tried to rinse again and even recleaned the area. No luck but it also hasn’t dried for very long. The entire house is fine other than just the porch ceiling. Here are some pictures of what it looks like. Any advice would be greatly appreciated! Should I call a painter, clean with something else or what? The porch ceiling is hardy board and is 2.5 years old


I’ve never seen such a beautiful “starlight” motif on a porch ceiling before. They should have paid you extra for that.


This is why we don’t wash hardy board. Your in luck since you learned your lesson on a porch ceiling.

Imagine learning that lesson on a 5,000 sq ft home with Hardy board siding


My guess is that the original application of house mix was probably left on too long before rinsing and it started to dry in areas where the mix beaded up into droplets and possibly left SH concentrated stains in the shape of drops. Or you just didn’t rinse enough and there was still SH mix left on the ceiling that pooled into drops and dried. You could try and stronger mix in a pump sprayer and let sit for a few min and rinse well.


The bleach affected certain pigments of the paint. It’s a known issue with Hardy plank…

Call a painter


Thanks for the advice but we wash them several times a week with no spotting.


I avoid hardi-plank homes as well unless it’s white and is the newer kind that comes painted from the factory. I haven’t had any trouble with those. But I usually pass on painted hardiboard homes


you Could wash 100 with zeroissues and then have a 20k insurance claim for a new paint job out of nowhere. I’ve had one bad experience and won’t touch another one again


I agree! This will be our last one for sure. Lesson learned! Thankfully it’s just a small area on the porch.


We will be avoiding them from now as wel!


I live in Alabama and a majority of the homes built in the last 7-8 years have hardiboard. Sometimes you have to change up your soap and your bleach concentration for different types of siding. Elemonator is good but not always the best option.

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Is it a smoking area. Nicotine residue will do the same thing and can be removed with a stronger solution. We see it all the time inside lanai’s above we’re everyone sits and smokes

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I agree with @florida_condo_cleani that doesn’t look like something your hw mix did

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Yeah almost every home being built around us is hardie board now! Thanks for the comment


I’m not sure if it’s a smoking area. They have only been in the house a year and don’t seem to be the smoking type. I do feel like it wasn’t our mix. I’m confident in that but we are willing to make it right for the sake of our name! Thanks for the comment.


Yes, half to two-thirds of houses here are hardy board or the generic version. Hard to skip that much of tje market.


Actually, sometimes those spots will go away sometimes in a day or so once it drys really well. Hopefully will in this case.


Any painted or stained surface, we do a test spot on to ensure no negative reaction with paint or stain.


If didn’t do hardi houses Id never get houses. I’m not sure why the hardi matters so much. It’s painted. I’ve seen those spots go away after a day or two. If not rinse again.


Keep everyone updated on the outcome please