Do It Yourself Mold Remediation
The AP reported this morning that a historic Miami courthouse has been partially shutdown after a “U.S. Public Health Service study [ . . . ] found mold throughout the 166,000-square-foot building.” In fact, the building was making its occupants sick.
Employees have repeatedly complained about such health problems as sneezing, coughing, runny noses and lung irritation, as well as musty odors and water leaks. One law clerk in a second-floor office works from home because of “poor indoor air quality and mold,” the report said.
Note those symptoms. They read like a quote from the National Center for Environmental Health for mold spore exposure.
So what are we to do?
For do-it-yourselfers, here’s a quick mold remediation and prevention list:
- Problem: Leaking air conditioning ducts create moisture around the ducting, creating an environment for mold spores to grow.
- Solution: Seal all duct joints with flexible mastic.
- Problem: Impermeable vinyl wall coverings trap moisture between the wall covering and the sheet rock, creating an environment for mold to grow on the sheet rock, thereby degrading it.
- Solution: Use a primer with meldewcide in it on sheet rock prior to installing the wall covering. (Zinsser Bullseye® is my preferred choice of mold killing primers.) Also ensure that any vinyl wall coverings you buy have a permeable paper backing that allows it to “breathe” so that moisture will evaporate naturally.
- Problem: The laundry room.
- Solution: Laundry rooms should have a floor drain and pan for the washing machine. I haven’t seen a washing machine yet that didn’t at one point or another leak, drip, or spill some water at some time — even if only during servicing or removal. Dryer vent runs should be kept as short as possible, and hose connections kept tight. Dryer air may be hot, but it’s also very damp.
- Problem: Water-resistant dry wall (“green board”) is often used as a backer board for tile work. In fact, in many places it’s still legal to do so. The problem is, “green board” is water resistant, not water proof. Over time it degrades and the tile pulls away, letting mold grow in the gap.
- Solution: As is now code in most places, cement backer board should be installed over water-resistant dry wall. It remains structurally sound even after repeated wet/dry cycles.
- Problem: Poor venting or no venting at all in the bathroom.
- Solution: At the very least, open a window. Better yet, especially here in the Pacific Northwest (where the outside air can be just as damp as the bathroom air), leave the door open for awhile after showers, and ajar as a matter of habit. Or, install an externally vented bathroom fan.
To get rid of existing mold growth, scrub the affected areas with a ½% chlorine bleach solution (i.e. standard laundry bleach), then prime and repaint. Make sure your paint has a meldewcide in it. (As stated above, Zinsser Bullseye® is my preferred choice for this.) If the mold problem was really bad, double prime with a meldewcidal primer before putting on your top coat.
- Solution: At the very least, open a window. Better yet, especially here in the Pacific Northwest (where the outside air can be just as damp as the bathroom air), leave the door open for awhile after showers, and ajar as a matter of habit. Or, install an externally vented bathroom fan.
- Problem: Damp/wet/flooded crawl space. Here in the Pacific Northwest, the housing bubble grew this problem to epidemic proportions. New housing tracts were been built on wet lands and sub-areas were dug to as much as a foot below grade. And of course, no thought was given to drainage, nor was it required by the approving building department.
The result is a craw space so damp (or actually flooded!) that insulation becomes soaked. Not only does it no longer insulate, it becomes a host for mold.
- Solution: Depending on the severity of the problem, a sump pump may need to be installed in the crawl space. This will require grading the sub area so that water will flow into the basin. Then a vapor barrier should laid over the ground. 90% coverage is the minimum tolerable, but often not achievable due to low clearances. Do the best you can. Re-insulate as necessary and possible.
- Problem: Improper flashing of roof, doors, and windows. Once water is behind the barriers designed to keep it out, the wood framing and sheathing soaks it up, creating an environment for rot and mold.
- Solution: You can tell if you have a flashing or caulking problem around windows and doors fairly easily: The walls around the doors and windows will become discolored. Roofs should be visually inspected every year or so to make sure the the shingles are in good shape and that flashing is not rusting away. Fixing discovered problems, however, may not be so easy. Whether it’s the roof or the doors and windows, if you have a flashing problem, it will require anything from minor to major disassembly of the roof or trim and siding to correct.
Failed caulking around windows is more in the do-it-yourselfer’s range. Scrape out all the old caulking with your trusty 5-in-1 tool and clean the groove. Prep and prime the wooden framing around the window (but not the plastic or metal window itself). Once the primer is dry apply a bead of good door and window caulk. (I prefer Sikaflex® caulking.) Finally, when the caulking is dry, prime and paint it.
- Solution: You can tell if you have a flashing or caulking problem around windows and doors fairly easily: The walls around the doors and windows will become discolored. Roofs should be visually inspected every year or so to make sure the the shingles are in good shape and that flashing is not rusting away. Fixing discovered problems, however, may not be so easy. Whether it’s the roof or the doors and windows, if you have a flashing problem, it will require anything from minor to major disassembly of the roof or trim and siding to correct.
- Problem: Drainage. A huge problem here in the Pacific Northwest, where we live in a temperate rain forest that gets over 100 inches of rain every year! It’s also one that architects and designers are famous for overlooking.
An improperly drained property can flood crawl spaces seasonally. It can also allow water to “wick up” into the structure anywhere wood comes into contact with the moisture. And once that happens, you have both a rot and mold problem.
- Solution: Unfortunately, there is no one solution to fix all drainage problems. And even the most common sense elemental solution — properly grade the property so that water runs away from the building — can be intimidating when you compare the size of your shovel to the size of your yard.
Sometimes more drastic measures are needed to protect the building: French drains, drainage walls with lift pumps, and drain fields are all common methods of removing excess water from the property, there-by keeping the house itself dry.
- Solution: Unfortunately, there is no one solution to fix all drainage problems. And even the most common sense elemental solution — properly grade the property so that water runs away from the building — can be intimidating when you compare the size of your shovel to the size of your yard.
- Problem: Use of dehumidifiers — especially portable dehumidifiers. Yeah I know, they’re supposed to dry out the air, thereby reducing the mold problem, not contribute to it. Unfortunately most dehumidifiers are improperly maintained, so they end up providing both a growth medium and a distribution system for mold spores.
- Solution: If you’re going to use a dehumidifier (they’re really not all that effective), properly clean and maintain it. And be sure to add some antimicrobial solution (available in hardware stores) to the drain pan every time to dump it.
(Oh, and if you’re one of the few people that has an air conditioner in your home, the same thing goes for its the condensation pan. Clean it thoroughly with that ½% bleach solution mentioned above before firing it up in the summer, then put some of that antimicrobial solution in the pan to prevent mold growth.)
- Solution: If you’re going to use a dehumidifier (they’re really not all that effective), properly clean and maintain it. And be sure to add some antimicrobial solution (available in hardware stores) to the drain pan every time to dump it.
- Problem: I did everything you said and the mold came back!
- Solution: Yup. We can’t get rid of all the mold. In fact, experts suggest we see less than 10% of the mold that’s really there. Even full blown remediation doesn’t completely eliminate all mold spores from a building. So there’s one more thing you need to do to keep the little buggers under control:
You have to take steps to keep the entire building warm and dry and well ventilated year around. I mean, from the attic spaces to the crawl space. Usually that means installing a good building ventilation system that’s equipped with a dehumidifier.
This doesn’t kill the spores. Rather, the air changes remove any air-born spores from the building, while at the same time forcing those that remain in the walls and crawl spaces and so on to go dormant so they’re no longer a problem. Unless you do this, in our damp North West climate, the mold spores will begin to grow and spread again even before that new paint in the bathroom is dry.
- Solution: Yup. We can’t get rid of all the mold. In fact, experts suggest we see less than 10% of the mold that’s really there. Even full blown remediation doesn’t completely eliminate all mold spores from a building. So there’s one more thing you need to do to keep the little buggers under control:
If your mold problem isn’t bad, working your way through the steps above will put an end to any mold related health problems you might be having. If your house is really sick (“sick house syndrome”), and doing the above isn’t solving your problem, you’ll need to do full remediation to save the building. For that you’ll need a professional.
Technorati Tags: mold, mold remediation, sick house syndrome, do-it-yourself projects, indoor air quality
