Bleach is a very powerful chemical. It can kill just about any living thing it touches, it breaks down the chemicals that cause stains, and if you mix it with an ammonia-based cleaner it will create a deadly gas. Those first two properties make it sound like it’s the perfect chemical to use on mold since you definitely want the mold to die and you want the stains it leaves behind to vanish. However, bleach isn’t the most effective mold-killing chemical.
Surface Level Problems Are Fine…
If the mold you’re looking at is on something smooth and hard like solid plastic or a metal panel, bleach will definitely kill the mold and erase the stains. However, bleach is caustic and may destroy any dye or paint on the surface you wash. Bleach is safe to use on plastics, but you’ll need to dilute it first and wash thoroughly after.
…But Bleach Can’t Penetrate
Of course, mold often grows on porous materials like concrete and untreated wood. Sometimes these materials have a layer of paint or other seal protecting them, but over time this seal can break down. This lets the mold go much deeper than the discolored patch you can see on the surface, and if all you do is scrub off this surface patch the mold will quickly regrow and cover the same area again.
You need the bleach to reach into the stone or wood to kill the mold, and unfortunately it’s isn’t good at doing that. Instead, the active chemical in bleach will stay on the surface even as the water solution it’s in penetrates deeper in. This means you’re giving the mold nothing but more water to grow with, and as soon as the bleach removes the surface layer the deeper mold will start growing out to replace it.
So What Does Work?
When you’re up against a mold bloom, your best bet is a specially made fungicide. These custom chemicals are not only good at killing mold, they’re also good at penetrating rock, wood, and drywall to reach the mold no matter how deep it grows. You should also inspect the affected area for damage. If mold grows in a single spot for too long, it can damage the material to the point where you should cut it out and replace it. That may sound drastic, but it might be what you need to completely remove your mold problem.
Bleach is an effective cleaner for many household stains, but it’s also a dangerous chemical and not appropriate to use on every problem. Mold growth is one such problem, because even if bleach doesn’t damage the material you’ll only be able to kill the mold on the surface. To take care of the rest, you’ll need a special fungicide or the help of a mold remediation service. A professional will know what kind of service you’ll need and why the mold is growing in the first place, and by working on both they’ll minimize your mold problem.
