RICK'S MOLD FIX #1 (A response to a big time mold problem in a crawlspace)

There are volumes of articles on mold and the effects it has on our health, but I’ll try to keep this simple, if possible.  The way I like to explain enviroillness to my clients is to have them imagine a wall full of light switches, and these switches represent predispositions to illnesses.   No one is sure of all the factors that trigger these predisposition switches but most who have spent time studying IAQ issues agree that certain environmental conditions flip the switches to ON.   Molds and fungi are at least in the top ten of these switches.

Popular Mechanics wrote about dirt crawl spaces and reported that in 1000 sq. ft. area, that does not contain standing water, as much as 18 gallons of water per day can conduct through the floor into the living area.   The following is a list of recommendations that I recommend for your situation: 

1. Buy a mantle hygrometer and measure the relative humidity in at least two different areas in your home. In a cool climate period if the RH is 50 or over this is too high and you need to reduce this.  If in the summer the RH is this high while running your air conditioning it will cause your AC unit to work too hard to carry off moisture, which will be inefficient, expensive and hard on the unit.

2. Make sure that the rainwater from your downspouts is getting away from your foundation. Use downspout extensions and/or build up the soil around your foundation to obtain proper fall to carry water away from your house. It is extremely important to remove the water source.

3. Have a sump pump installed in your crawl space.

4. This is controversial, but I attended a Department of Energy conference last winter and a man whom I greatly respect was one of the keynote speakers and he recommended closing off your crawl space vents. I had been wondering about CS vents because I knew that natural pressures exfiltrate at the top of homes, which causes infiltration at the bottom. Crawl space vents will draw in moisture and mold spores from outside and the spores will have a perfect breeding environment.   Most local code officials require these vents and this is the controversy.   Closing the vents will stop the infiltration of moisture from the air outside and airborne mold spores as well.

5. Once you control the standing water problem, install 6 mil poly over the entire dirt area with a lap up the wall between 6” and 8”. This will prevent ground moisture from rising into your living space.

6. If you can, install a crawl space vent fan that blows out and causes the CS area to go slightly negative. There is a great fan called "The Preventilator" that will not use near the energy that a dehumidifier or a full time fan would require. See Tool Info

7. If you have return air and supply ducting that runs through your CS have a contractor “Mastic Seal” all the joints. Make sure they do a thorough job. Most contractors want to get out of a CS as fast as they can and will cut corners.

8. Finally, even though there is a bunch more, pull back a corner of your carpet upstairs and see if mold is present.  If you see black stuff (don't touch it, breathe it or disturb it) this is mold and the carpet will have to be safely removed.   No cleaning devise can remove molds.   Molds grow at incredible rates, all they need is moisture and cellulose.   If the rug cleaners miss one spore you’ll have the problem back in no time.   Molds spores are microscopic, if you drop one 4 ft. from the floor, it will take an hour for it to reach the ground.

9. Bleaching the walls has been the standard mold clean-up procedure. Because moisture and mold are always in the air, mold will return to the wallboard in a short time.  If there is mold is on one side of the wall board it is likely on the inside of the wall as well.  The remedy is to have the wallboard removed.   If the ex-filtration/infiltration problems are eliminated this may not be necessary.

10. Finally, the most important step to mold prevention is to eliminate the ex-filtration/infiltration loop.   This can only be accomplished by a contractor who is trained in the operation of the "BLOWER DOOR."   The Blower Door is a powerful fan that is installed (temporarily) in your front doorway that when turned on depressurizes your home so that the operator can sleuth out leakage sites.