Do you have floor joists in your crawl space that look like the one to the left? In case you can't tell how bad it really is, just click on it to see a bigger version. When you do, you'll notice the 'furries,' as one of my friends called the microbial infestation growing on that wood. What's going on here? Why is stuff growing on the wood down in the crawl space? Well, I'm not a mold expert and haven't identified the growth here as mold, but if it is mold, here's what's necessary for it to grow: So, of the four requirements for mold growth, the one we have most control over is moisture. Keep the materials and the air dry enough, and we won't have a mold problem. Have you measured the relative humidity in your crawl space? When I was doing improvements on homes, I'd install a digital thermo-hygrometer with a remote sensor in the crawl space so the homeowners could track the relative humidity. If you're not doing this yet, and you have a crawl space, get yourself one of these devices now.

OK, so you've measured and determined that you do have high relative humidity in your crawl space. That's not unusual at all, especially in a humid climate like we have here in the Southeast. Where's the moisture coming from? And why is the humidity in a vented crawl space higher than the outdoor relative humidity? Here are three reasons. The first problem to look for is bulk water. If there's standing water in your crawl space, you have either a drainage problem or a plumbing leak. You need to fix this immediately. Having a pond under your home is a bad, bad idea. In the photo above, the problem was that the back yard sloped down to the house, bringing water up to the foundation wall. Since it was just a crawl space, the builder didn't put any kind of water proofing on the concrete block or grade the yard properly to keep the hydrostatic pressure from building up against the block wall. You can see the result here. This was a new house with a serious bulk water problem. The joists were already growing stuff, and the fiberglass batt insulation was getting heavy and falling down.

2. Moisture Evaporating from the Ground In the photo above, the ground was partially covered with a polyethylene vapor barrier. The dirt that wasn't covered looked dry, but when I pulled the plastic back, I found that there was a lot of moisture in that soil. The soil that looked dry only looked that way because it was constantly evaporating moisture into the air of the crawl space. cheap air purifiers australiaThe foundation walls can also evaporate moisture into the air.air cleaner assembly chevy What do you do to solve the problem? best air purifier heaterCover it all up with a vapor barrier! 3. Outdoor Air Coming in through the Crawl Space Vents Some people find this hard to believe, but when you bring outdoor air into the crawl space, the relative humidity actually increases.

Think about it this way: When air enters the crawl space, it cools down. Cool air cannot hold as much moisture as warm air, so the air that enters is now closer to its saturation point (which we call the dew point). It might've been 60% relative humidity outside (relative to a temperature of 90° F, say), but when that air came into the crawl space and cooled down to 75° F, the relative humidity jumped up to 95%. The numbers here come from the psychrometric chart (invented by Willis Carrier, the inventor of the modern air conditioning system), which relates temperature and humidity of air. If you've got a vented crawl space with high relative humidity caused by one or more of the above, to solve the problem, you've got to remove the causes. Bulk water is solved by fixing the drainage or plumbing problems. Water evaporating from the ground or coming through the vents can be fixed by encapsulating your crawl space. One thing that does NOT work is to try to treat the symptom by installing a dehumidifier.

If the problems get really bad, though, you can always keep some kayaks down there so you can get around easier.Air quality is extremely important, yet for all the pollution you're exposed to outdoors, your indoor air quality can be even worse! Jim Pearson has 30 years of experience in this business, and has been working with mold for nearly as long. When scams within the mold remediation industry became a problem, an official professional mold remediation standard and reference guide was written, which is certified by the ANSI (American National Standards Institute). This document describes the correct way to address molds, so make sure any remediator you hire follows these standards. Pearson was part of the group who wrote this standard, and during the last four years of its creation, he served as the chairman of the consensus body writing it. Obviously, mold is the inevitable outcome whenever you have some form of water leak or flooding in your home. Poor drainage around your house or something as simple as clogged gutters or leaky plumbing can also cause problems.

However, high humidity is another a risk factor. Aside from flooding, poor ventilation is the second major cause of mold. You really don't want to keep any kind of wet materials around the house for any length of time (think forgotten laundry in the washing machine, for example, or wet beach towels tossed in a corner), as it can cause mold to start to grow. Mold only needs two things to thrive: water and food. Its food is any organic source, such as paper, dry wall, or wood for example. Indications that your environment has, or is conducive to mold growth include: ✓ Water damage from putting out a fire, or any kind of water intrusion, whether internal (like a leaky pipe) or external (such as broken shingles) ✓ Condensation on windows (indicative of high humidity in an environment that can cause mold growth especially around the windows or the window sills) ✓ New or increased allergy symptoms ✓ Cracked or peeling paint, or loose drywall tape/wall paper

✓ Rusty metal (as it's a sign of high humidity) ✓ Drawers or doors that stick Naturally, once you have visible mold growth, it's time to take immediate action. The key to mold control is moisture control, so it's important to wipe up the excess water and dry the area and any affected items within 24 to 48 hours of the leak. Once it's dry, you need to clean up the mold. "You don't cover it up. You don't paint it over. You don't spray bleach on it. You don't do any of that kind of stuff," Pearson warns. "And you don't mess with it without protection." As a first step, Pearson suggests taking "the middle of the road approach." "What I want you to do is take a reasonable approach to this. It's not going to kill you. It probably won't even make you sick. But you're not supposed to have mold in your house. The Centers for Disease Control is very clear about that, the EPA is clear about that. If you see visible mold growing, there is a problem there and you need to correct it.

I'll tell you -- there is this mold that's called condensation mold. It's a mold that forms on a wall in the condensation layer on the wall. For example, if it's super cold outside and you have poor insulation in the home walls, if you have a couch pushed up against the wall, you may get a little condensation there because there is not enough airflow in the winter time… So you might get a small patch of mold.If you're dealing with a little patch of mold that's less than the size of a dinner plate, you can take care of it yourself quite simply. First, do not spray anything on it. Don't blow any air on it to dry it out… [T]ake a microfiber or a terry towel, a little hot water and just a little bit of detergent. Any of the dishwashing detergents are fine. You don't need to disinfect. Just get that and kind of sneak up on it and place it over the mold. Don't be vigorous, and move slowly. Place it over the mold and kind of gather it up into the palm of your hand and then wipe the rest of it off and you're done.

It's just that simple." Some people suggest using vinegar to destroy visible mold, but this might not be such a great idea, according to Pearson. "Frankly, I think it's fruitless to attempt to kill a mold with anything," he says.Poisons, toxins, and allergens… they're not living things. The only thing you can really kill with anything that you can put on it would be the infectious or opportunistic types of mold. There are a few and they are very dangerous.But frankly, we're not in the "killing mold" business, we're into the "removing of the mold." Remove the source of the water and remove the mold itself and you're pretty much good to go. I say that because I don't want people trying to put on things that they hear about, bleach and home remedies and things to wipe this stuff up thinking that they're going to kill it, because that's not the goal. The goal is to stop it from growing…" The reason for using detergent and hot water as opposed to vinegar when removing mold is because the detergent acts as a surfactant and breaks down surface tension.

This is important because mold is hydrophobic, so it repels away from water—and away from vinegar, or any kind of aerosol spray. This actually causes the spores to scatter and SPREAD. Now, if you have moldy wood, such as a moldy baseboard, cabinet, or wall, then soap and water is not going to remedy the problem. That's when you want to call in a professional, because there's no telling how bad the problem might be. The visible portion may just be the tip of the iceberg. So, how do you pick a professional? "They really should have some certification in the cleanup, or some kind of training… There are considerations such as airflows, negative pressures, HEPA filtration, personal protective equipment, deconstruction rather than demolition; there are so many factors to consider.Pick somebody who belongs to an association or some sort of industry, [that has] ongoing training and schooling and certification," Pearson suggests. You can find contractor or professional listings on the following sites.

Both the IICRC and NORMI are certifying organizations for mold remediation, but the IICRC certification is perhaps the most widely used: Keep in mind that a mere certification or listing may not be enough. Also evaluate the remediator's qualifications and insurance (liability as well as workman's comp). With the ACAC, there are a few different levels. Once you've remediated the mold, or if you don't have any to begin with, you may want to consider addressing the air quality. Ozone generators effectively remove odors, even some of the most persistent ones, such as: Another useful tool in the remediation process is the photocatalytic oxidizer, which employs UV light on titanium dioxide. Pearson isn't fully convinced that it is an effective way to remove mold spores, but the UV light does destroy bacteria and viruses. Always remember however, you must remove any mold FIRST, before you consider purifying the air of any lingering odors. "My analogy is: you got a dead rat in your ductwork.

There are two things I can do. I can put perfume on it and it will smell like a dead rat with a lot of perfume on it, or I could use ozone—but if you leave the darn thing in there, it's going to start smelling again. Removal first, and then you can approach these other issues." According to the Environmental Protection Agency (EPA), poor indoor air quality is one of the top five greatest environmental risks to public health and well-being. Amazing as it sounds, indoor air can be five to 10 times more polluted than outdoors air! This is because there's a lack of ventilation, so contaminants build up and stagnant air is re-circulated. Common health problems that can be attributed to poor indoor air quality include: ✓ Fatigue and lethargy ✓ Poor concentration and forgetfulness ✓ Stomach- and digestive problems So what can you do about it? Regular duct work cleanings might spring to mind, but according to Pearson getting them cleaned more frequently than once every five to 10 years is unnecessary, as this is unlikely to resolve your health issues.

Here too, it's important to make sure the duct cleaner is certified and well-trained. A good resource is the NADCA (National Air Duct Cleaners Association), which created the standards and lists qualified HVAC technicians. In terms of making a difference to your health, Pearson suggests the following five guidelines to improve your indoor air quality: I would also suggest adding a few house plants, as they can act as natural air purifiers. NASA, along with the Associated Landscape Contractors of America (ALCA), conducted a classic study on the benefits of plants on indoor air, and found that houseplants were able to remove up to 87 percent of air toxins in 24 hours. They recommended using 15 to 18 "good-sized" houseplants in 6- to 8-inch diameter containers for an 1,800 square-foot house. Many more details on the issues of mold and air quality are discussed in this interview—far too many to include in this summary, so for more information, please listen to the interview in its entirety or read through the transcript.