Interesting chat about mold

I talked with a retired facilities maintenance contractor about using bleach to kill mold and mildew. He pointed out the SH doesn’t actually kill the growth but ‘deactivates’ it, so we can rinse it off only to have it grow back later.

He had to do a cleaning job at an ‘eco-sensitive’ job site, and his most effective solution was water and oregano oil as he said it actually kills it.

Anyone ever hear of this?

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This seems to be a popular refrain among the applewash/spray wash academy/soft-wash with a capital S hyphen W crowd. One of my competitors posted something incomprehensible about it. I think it’s supposed to make them seem like they have some special chemical that the other guys don’t?? Idk. Googling “does bleach kill mold” returns a resounds yes. It kills plants, grass, flowers, but mildew stands strong? Nah

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It actually doesn’t fully kill mold and algae. Only a few chemicals do. Shockwave is one we use at my previous employer.

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Shockwave is what they use when getting rid of mold in houses that have been flooded. It’s good stuff apparently. It runs about $40 a gallon last time I checked.

That was one of his contracts, he was tasked to kill mold in a flooded building basement. It was an interesting conversation. Wouldn’t it be something if oregano oil worked better than SH…plus it smells a lot better.:+1:

What I’ve read is that it boils down to porous vs. non-porous surface cleaning. Mold remediation inside homes involves many porous surfaces. The bleach doesn’t have the ability to penetrate and kill on a prolonged basis. The chlorine evaporates off quickly, leaving essentially salt water which invites further mold growth.

For non-porous surfaces (like vinyl, aluminum, or painted siding), bleach is great for sanitizing and killing growth.

This is just a very dumbed down explanation, and I’ve probably gotten a few details a bit off, but I’m no @CaCO3Girl


Thanks for the tag Infinity.

Okay, bottom line. Does SH kill mold, YES. But only the mold it touches…and there is the hitch people. Oregano oil isn’t my pesticide of choice, but it stays around faaaaaaar longer than SH does.

Nothing can claim to kill mold on a porous surface. Not even any EPA registered pesticide. So what I have told people is to kill off the mold with SH, THEN leave behind an antimicrobial on the porous surface. This will inhibit the mold from growing for awhile.

However, BE CAREFUL if the surface has been painted. Many antimicrobials are the things turning paint different colors, such as IPBC (Iodopropynyl butylcarbamate - Wikipedia)

So, if the surface has paint you may want to try a different solution. I’ve had some success with spraying a sodium carbonate (soda ash) and water solution on the surface. Enough sticks around to make the porous surface alkaline, meaning a higher pH…and mold likes lower pH’s, so it doesn’t find the higher pH’s very hospitable, so it doesn’t grow.


Once or twice a year I get a potential customer who claims to me that bleach doesn’t kill mould it only bleaches it so you can’t see it. as there is an morning show where some woman tells people that in order to sell her magic product.

When I was early in business I had one customer have me use tea tree oil on a small area, it didn’t work and make my gear stink for weeks.

It’s kinda true mate. It does just bleach the top layer.

If it’s light mould, like the green stuff - it rinses off. But other stuff, like the black mould and lichen, it needs pressure to actually remove the dead mould, or it is in fact just bleached and still there.

It’s always been my issue with low pressure softwash systems. Not having the power to do a thorough job when needed. Hence the need for a pressure washer more than a softwash system.

It’s nice to have both - but only for chemical application I find.

If i have mold/mildew in my home. I clean it with 50% warm water/ 50% white vinegar in a spray bottle and wet it as little as possible then dry with a fan. My grandpa took some classes back when he had a carpet cleaning business and told me trying to kill mold with bleach(in your attic from roof leak or in your carpet from leaking air conditioner) will promote more mold growth. 🤷
I had both of thise problems it works well but you house smells like a pickle for a day.

Yeah, I did water damage restoration with a company one winter years back. Bleach is a big no-no for that kind of work. After the drying process, everything that wasn’t torn out got treated with some special mildewcide that was apparently pretty expensive stuff.

Many times we had to gut a place down to the studs, at least up to the water line anyway.

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