What is the best way to remove black mold from wood?

Specifically, the mold on my back porch is black mold. Is the best option to use something like Kilz over it?

  • 2
    Do you have a respirator? This is nasty stuff you don't want to breath. If you don't have a respirator get one, or call a professional to do the work.
    – Tester101
    Commented Sep 15, 2011 at 12:04
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    Have you had this "Black Mold" identified by a lab? I seriously dought you have toxic black mold on an outdoor porch, it is probably common plant mold. You must have it tested to know, the color doesn't mean a thing. Commented Sep 15, 2011 at 22:41
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    @shirlock homes - let me clarify: the mold is black in color, and pervasive across our porch roof (previous owners used OSB instead of outdoor plywood for the porch roof); it may not be "black mold", but it is mold which is black :)
    – warren
    Commented Sep 17, 2011 at 3:57

1 Answer 1


This is a problem best suited to the professionals, but if you must do it yourself the number one priority is the safety of you and those around you. This can be a very hazardous task, if you do not take every precaution to contain and remove the spores properly.

The first thing you'll have to think about is containment, you don't want to spread the mold spores while you clean the area. You'll want to seal off the area (under negative pressure) with plastic sheeting, making sure all seams are properly sealed.

Once the area is sealed off, you'll need the appropriate clothing.

  • Respirator
  • Tyvek suit (or other clothing that covers your whole body).
  • Rubber gloves.
  • Goggles.

Now it's time to start cleaning. Before you begin make sure the infected area is damp, this will minimize the chances the spores will become airborne. You'll start by scrubbing the affected area with a Borax-water mix (1cup Borax/1 gallon water) using a scrub brush, to remove as much of the mold as possible. Wipe up any excess mess with rags, and dispose of them in a thick plastic bag (Contractor bag). Rinse the area with a small amount of the Borax solution, then let it dry completely. Once dry you'll want to pour a small amount of disinfectant (Isopropyl Alcohol), and allow that to dry as well.

Now that the mold has been removed, you can paint the affected area with Kilz if you like. The most important step at this point is to address the moisture problem in the area, or it's likely the infestation will return. You'll want to do what you can to make sure there is no standing water in the area, and that any moisture drains away and dries quickly.

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    I'm not sure he has black mold, but we start by spraying a mild solution of specially blended industrial anti-fungal bleach on effected areas to kill and ground the spores before remediation and cleaning begins. You are absolutely right that mold remediation should be left to professionals. I do mold ID testing all the time, then sub clean-up to pros. Commented Sep 15, 2011 at 22:49
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    I should have mentioned. Black mold, although there are hundreds of types of mold that appear black, is highly toxic and can be fatal if ingested in large doses. No untrained person should attempt to remove it under any circumstances. I can not emphasize enough the need to have tests done before proceeding. Commented Sep 15, 2011 at 22:54

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