Crawl Spaces and Bleach – Mold Myth!

Have you had the unfortunate happen? Your termite guy, hvac guy, plumber or others come out of your crawl space and told you “I think you’ve got some mold down there”.

Oh boy, now what!

One of the most pervasive myths is that molds can be killed by just spraying it with bleach.

This is exactly the wrong thing to do.

First, it takes a trained specialist to view and sample the growth and have it sent to a lab to be tested. It is impossible to look at it and tell you what it is and whether it’s ‘active’, or giving off spores.

Any kind of fungi has 3 things you need to be aware of:

  1. it’s a symptom. They need a food source (in the crawl space it’s the wood) and moisture. Have ‘mold’? You have a Moisture Problem.
  2. It’s IN the wood. Any mold is like a mushroom. The ‘body’ is in the wood spreading. What we see on the surface is the fruiting portion of it, releasing spores to spread.
  3. It’s EATING your wood! It truly is breaking down the cellulose, the portion that holds all the wood fibers together! Give it enough time and it will weaken the wood until it needs substitute.

So how do you treat it?

Well, The active ingredient in bleach is great at killing molds – but only on hard and impervious surfaces like tile and grout.

Beware any contractor that tells you they can just spray it with a bleach/water mix. They do NOT know what they’re talking about!

Since household bleach is about 99% water and 1% active ingredient, if you spray or wipe it on the wood in the crawl space you will kill what’s on the surface, but end up adding more moisture to the wood.

Further, the chemical structure of bleach (sodium hypochlorite) truly prevents it from absorbing into the wood. The water soaks in, the ‘bleach’ sits on the surface gassing off.

Read that carefully! Molds/mildews need moisture, and when you treat your crawl space with bleach you give the wood more moisture! I’ve had homeowners ‘go cheap’ to remove fungi by spraying with bleach, and called me a associate of weeks later complaining the problem was worse!

Want more proof? OSHA no longer recognizes bleach as an appropriate treatment and the EPA edited their guidelines to remove bleach as a remediation method.

Either use a specialized and have it re-mediated or at the minimum go to your home improvement store and buy a real mold removal chemical.

Most importantly, you might kill it but you need to address the conditions that allow enough moisture in the wood to grow it!

You can remove the growth, possibly monthly, but if you don’t change the ecosystem that allows it to grow it will consistently come back!

There are anti-microbials that hinder fungi growth, and these can be sprayed, wiped or rolled on the wood. However, if the conditions are right for growth, these anti-microbials can not stop it forever! I’ve seen homes where the fungi just grows right by it.

Leave a Reply