Our good friend and regular contributor Joel McDonald sends in the following, a followup to his last article - in November 2008 - on locating possible black-mold outbreaks (a must-read for anyone considering buying a home, or rehabbing an older house):
Just kidding. It's not as bad as all that. Molds and their relatives are all around us. Their spores can be dormant for long periods of time, only to become active and start reproducing when conditions are right. The conditions they need, as you probably know, are moisture and not too much light. It helps if the place is poorly ventilated since that allows moisture to build up -- but with enough moisture many molds can grow even in a draft. Your basement, for example, is what mold spores probably dream of when they're resting. Damp, lonely, nobody coming around trying to bother you all the time -- absolutely heavenly, if you're a mold spore! Even in areas of the country that you might think of as being too dry for mold to grow, all that's needed is a chronic spill or a little leak in an unventilated space, and moisture buildup can lead to mold growth.
The question of how to prevent the growth of black mold is pretty easily answered - keep the environment dry. Do that and you've pretty much got the problem solved.
What about the condition where the mold has already gotten ahead of you, and it's growing one of your interior spaces? You'll want to remove the source of moisture, of course, and in most cases this can be done by using a dehumidifier. If there has been a flood or leak, and not just a normally-moist environment, then you'll have to first pump out or mop up, and use plenty of ventilation to dry the space. Use the biggest fans you can get. It may take days or even weeks, and you might be able to get started on mold removal in the meantime, but there's not much point in trying to get out all the mold if the place is still wet. You should at least wash off the surfaces with detergent and water, and spot-dry the affected areas as best you can while the space is being dried out. If wallboard is affected, and it looks like it is more than surface deep (warped or swollen panels) go ahead and remove the worst-looking part to expose the spaces between the studs and evaluate whether you have to remove more wallboard for drying and cleaning the inside of the walls.
When you have the humidity under control, you can start on the serious business of killing the mold.
You might prefer to just go to the grocery or hardware store and find a commercial preparation to do the job, but some people prefer to avoid the use of strong chemicals. The use of bleach is sometimes thought to be a strategy for getting rid of mold, but its use has not been recommended by the EPA and there are drawbacks to using it -- it can be dangerous to handle anywhere outside of a washing machine, and if combined with other common cleaning ingredients such as ammonia (Caution: Don't!) it can produce dangerous fumes.
For absorbent and porous materials such as insulation, carpet, and acoustic ceiling tile, you may just have to get rid of the material if is has mold growing throughout and not just on the surface. In most jurisdictions you can discard it with other household refuse that goes to a landfill, and it may be a good idea to put it in trashbags if you can. You can expect to have better success with walls and floors, particularly if they are smooth. Even with porous materials, though, there is a chance that a good cleanup might work; depending on what the material is and how much it will cost to replace, it could be worth your effort.
Cleaning Up Naturally
Plain white vinegar applied full strength is an effective mold killer. It may not restore the original appearance by itself, but any stain remaining after a good dose of vinegar will have no living mold and can be cleaned or painted over with a high degree of confidence that the mold that was there will not grow back. Spray or brush it on, full strength, and scrub a little if needed. The familiar smell is not too disagreeable for most people, and it will dissipate after a while.
Other natural remedies listed by the Household Mold Guide, which has a number of useful recommendations, are tea tree oil and grapefruit seed extract.
Mold should not be ignored. While you might think of it as nothing more than an unsightly mess or an inconvenience, it can cause a variety of illnesses and -- since it relies on the digestion of organic matter such as wood and fiber to live - it eats your house. Getting rid of mold, and preventing its recurrence, is worth whatever effort it takes. So you may have to move, really - move yourself to action and dry it out, clean it up!
This article was presented by the ultimate Boulder real estate specialists of Colorado, Automated Homefinder.