I have a lot of experience with black mold because of my side job. An ozone generator does a fantastic job of killing black mold. If you let it run long enough, it will get into the walls and kill mold growing inside those too. A few will argue that point, but I've actually torn out walls after the generator has run for 1-3 days, so I have seen this firsthand.
Most people don't let them run long enough which is why some will say it does not kill the mold in the walls. I let it run until I smell it as I approach the front door which tells me it has permeated the structure. I use a plug that runs outside so I do not have to enter. I unplug it, leave, and come back later to air out the house. Breathing ozone is harmful to health so airing it out thoroughly is necessary. I use fans to speed up the process of airing it out.
If the house is large, I close off portions and treat small sections of the house longer and multiple times. I agree there are limitations but think about it: If spiders and mice can find their way into homes through the walls, can't air penetrate the small cracks and openings in the walls also? I think most people rush through the treatment so the structure can be occupied again. I believe I am successful where others have tried because I take my time.
The homes I have treated have zero problems with mold years later, so I know what I am doing is working well. The ozone also kills things like spiders and bugs living inside the walls too. While it may help, it won't eradicate an active infestation of termites or carpenter ants. The structure must be aired out thoroughly before anyone occupies the building again.
If you have not solved the moisture issue first, new mold will grow. So, you need to solve that before or very shortly after you treat it.
I have been to an abandoned home someone wanted to salvage that had major roof issues that had 80-90% of the internal structure covered in mold. I could smell the mold before Clint and I approached the door. Through the windows, you could see thick mold growing on the ceilings, walls, cabinets, furniture, curtains, etc. We weren't even sure if the structure was sound due to all of the visible water damage from a badly neglected roof. We would not even walk into the place, and we told the person to tear it down. I reckon running the generator for a good long while and doing multiple treatments would kill all of it. However, in that circumstance, I wasn't willing to be the one who tested the limits of the generator. Even thinking about that place has me wanting a shower as I type. It was the worst I've ever seen while a building was still standing.
Another benefit is that ozone eliminates pet, smoking, and other foul odors which is helpful in a wide range of situations. One of my sons purchased a car to flip that had been previously owned by a very heavy smoker. When you cleaned the glass, the water turned yellow from the nicotine staining. He brought the car to me and I treated it for 24 hours. After the ozone treatment, you could not tell if anyone had ever smoked in the car.
I've had my ozone generator for a while and the exact one is not available anymore. The one I have is very similar to this one. There is some maintenance you need to do with them, so don't forget to read and follow the owner's manual. One can pick up side jobs as it gets out that you own one. :-)
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