|
| |
|
|
|
|
Articles
Part 1 Indoor Air Quality, Mold & Moisture, VOCs | This page -- See below.
Healthy Homes: Part 1 Note: These articles were published in Living Well, a monthly magazine providing health-related topics to the Fairfield, Iowa community. They accompanied a series of lectures presented at the public library. This is Part 1 of a four part series on healthy homes from a Building Biology perspective that appeared in the March 2004 issue. Parts 2 and 3 were published in the following two issues and featured the topics New Home Construction in April and Electrical and Magnetic Fields in May. A fourth article, discussing Radio Frequencies (Cell Phones and Cordless Phones), is expected to be published in the autumn of 2004. This month's article is on Indoor Air Quality, including mold & moisture, volatile organic compounds (VOCs), and fiberglass, as well as other sources of ill health in the indoor environment. Keeping Indoor Air Healthy A much quoted statistic from the EPA is that indoor air in homes and offices is more unhealthy than outdoor air. This began in the 1970s during the oil embargo when builders made houses airtight to seal in heat and save energy. Extra ventilation was needed but not always installed. At the same time, many new chemicals were used in upholstery, carpeting and draperies which added toxic volatile organic compounds to indoor air through "outgassing". This was in addition to paints and varnishes, as well as particleboard, which came into prominent use in cabinets, sink enclosures and counter tops. Vinyl flooring replaced linoleum, adding more VOCs to the mix. The result was a chemical soup that built up in these super tight homes causing ailments ranging from allergies and asthma to chronic fatigue. People in older homes did not have as much of a problem because air with toxic vapors diffused to the outside through leaky doors, windows, and plaster and lathe walls. Older homes may cost more to heat but they "breathe," exchanging toxic indoor air with the outside and keeping concentrations of toxic vapors to a lower level. Enter the vapor barrier. The thinking among building science in the 1970s was, and still is, the tighter you make a plastic seal the more air leakage you avoid and the less heat you will lose. This sounds good in principle but the thermodynamics of water vapor movement are more complex because the dew point, the point at which water vapor condenses, can occur on either side of a vapor barrier and at any point in a wall. If fiberglass is used for insulation the situation gets worse because fiberglass becomes damp from condensation and stays damp for hours losing its insulating capacity. This dampness leads to mold growth within 48 hours. This is a problem in super tight houses because there are always puncture holes in the plastic. As a result the pressure of water vapor trying to equalize itself on both sides of the barrier is quite strong. Austin, the first city to pioneer Green Building and vapor barriers in the 1980s, is also the first city to ban them ten years later. The solution is to build a "breathable" wall that still insulates well. This concept was introduced in the last issue of Living Well and will be covered in detail in the article and lecture in April, when we discuss New Building Construction. Suffice it to say walls and foundations can be built that do not grow mold, even if liquid water leaks in from plumbing or rainwater, and these homes outperform homes built the traditional way. For existing homes, there are strategies to avoid the creation of mold in walls and basements by controlling its causes, which are: 1) a biofilm to feed on, which is everywhere on earth; 2) darkness; 3) still, non-moving air; and 4) moisture. The trick with mold control is to keep air circulating and to reduce moisture content. Moisture can come from three sources: 1) condensation; 2) "rising damp" or seepage through foundations in the basement; and 3) a water leak from plumbing or rainwater. An extensive foundation and slab protocol is provided for builders in the new building protocol that I have compiled, which provides steps to build a mold-free basement and home. This will be reviewed next month and was introduced in the February issue of Living Well. In existing homes, the way to control mold growth includes keeping moisture levels below 65% relative humidity throughout the house, keeping air moving, and keeping temperatures up in basements and crawl spaces. You must also maintain well built roofs and walls and immediately fix any water leaks whenever they occur. If building materials and carpeting get wet from a leak, you have 24 to 48 hours before mold sets in. After that it is too late. The water can dry and the active mold will die, but mold spores remain which become airborne and can cause allergies in some occupants. Plus as soon as the materials get wet again, the mold quickly regrows. We therefore recommend removing porous materials that became wet and moldy but only after you have found and fixed the source of the leak. Building Biologists are trained to detect moisture levels in building materials, identify their source, and recommend plans for remediation. You can clean a small mold problem yourself if it is less than ten square feet in size. A mold inspection can identify the area and make recommendations. Professional mold remediators are needed for larger jobs. If you do it yourself, non-toxic alternatives to bleach exist that kill mold, available at Green Building Supply in Fairfield. The EPA has guidelines at www.epa.gov/iaq/molds on do-it-yourself mold clean-up for small jobs. Condensation is a problem in older basements where the asphalt on the outside has deteriorated and cracks have formed. Water seeps in and water vapor condenses on the cool inside of basement walls. Protocols exist in the new building manual to prevent this from occurring in new homes, but for older homes, short of digging up your foundation and applying these new products (which you may choose to do if a problem is severe enough), the next best alternative is to keep your basement temperature above outside soil temperature, usually 55 degrees F. This drives air out through the foundation. Run a dehumidifier that permanently drains to a floor drain, and keep air circulating. Open the basement windows in warmer weather to keep air moving. Remember, mold does not like moving air. This is a controversial recommendation, but I am told the old timers around town agree with this, and you keep your basement condensation and mold down in the warm, humid months. If you have mold growing in your basement, after you change the temperature, humidity and increase the air flow you can clean and disinfect the mold with Ultimate Disinfectant and Cleanser from Envirox. Then apply a non-toxic basement wall sealant and mold suppressant, such as those made by AFM company. These products are available at Green Building Supply. Downspouts that actually drain rainwater away from the foundation are crucial for keeping basements dry. Many basements are damp because downspout extenders get knocked loose by a lawn mower or fall off. Rainwater then pools next to the foundation and seeps into the basement. Likewise underground downspout drainage systems get blocked over the years. It is better to drain rainwater away from the house in above-ground downspout extenders made of metal or flexible hose. Keep gutters free of leaves and debris. Bank the earth slightly up against the house so rainwater drains away. Ventilation is necessary in bathrooms and kitchens, which tend to get damp. Open the window or use exhaust fans in the bathroom when showering and in the kitchen when you boil water to cook. Make sure the exhaust fans vent directly to the outside, not to the attic. Use fans throughout the house to keep air circulating. Run air conditioners to keep humidity low (although Building Biology has alternate strategies to cool your house). A good furnace filter is necessary for healthy indoor air quality. Air filters made of spun glass are called "boulder catchers" by the profession because they let most of the dust and mold spores pass through. Electrostatic filters attract more of the particles but they still let some through. It is better to use a pleated filter with as high a "MERV" rating as possible, possibly adding it to an electrostatic filter if you have already invested in one. Dust can build up in your air ducts so have them professionally cleaned every few years. Mold can also grow in air ducts that are not insulated. It also grows in the condenser coil in your air handler and in central humidifiers that have a water reservoir rather than a flow-through method. These can be checked for and cleaned. If you have a crawl space and air ducts run through them, seal all the ducts with mastic tape to disallow humidity to leak out from upstairs room air and condense on foundation walls. This forms mold. Also keep the crawl space warmer than the outside soil, again generally 55 degrees F. Line the outside of the ducts with cotton insulation, not fiberglass. Superior Air Ducts in Houston (http://www.superiorairducts.com) makes a semi-flexible air duct that is much stronger than the fiberglass-lined flexible ducts. They do not allow fiberglass fibers to enter the air stream when the inner lining breaks (which is pretty tough in these models) and they can be professionally cleaned, which fiberglass flexible ducts cannot. Air purifiers are also helpful to reduce dust, mold spores and toxic vapors. They come in a variety of makes and models. There is a wide range of opinion on these units and I respect the opinions of the many experts on this subject we have in town. My recommendation is that you want to use an oxygen generating unit that does not produce nitrous oxide by-products, which are produced when the nitrogen molecule, N2, which makes up 70% of room air and is usually inert, is broken apart along with the oxygen molecule, 02, when it is broken apart to make ozone or higher weights of oxygen. This important issue will be discussed in detail at the lectures. Volatile Organic Compounds (VOCs) Any compound made of carbon is considered "organic." If it vaporizes at room temperatures it is also considered "volatile." This includes formaldehyde (which thankfully has been reduced in carpeting since the early 1990s); toluene and xylene from copiers, printers and other office equipment; various chemicals from paints and sealants; and natural gas and products of combustion such as carbon monoxide from gas ranges, furnaces and hot water heaters. Tests exist to sample these gasses and VOCs. Natural gas leaks occur in gas lines, ranges and gas valves on the furnace or hot water heater. Carbon monoxide leaks are due to cracked heat exchangers in your furnace or a problem in your stove. Back drafting from a chimney can cause carbon monoxide in the house. These problems can be identified in an environmental inspection and fairly easily remedied. VOCs from wall-to-wall carpeting, cabinetry and upholstery are more problematic. The misconception has developed that when new carpeting and paint loses its initial smell, it is safe and you get used to it. What has developed over the years, however, is the rise in such chronic diseases as asthma, allergies, chronic fatigue, immune deficiencies and even cancer. Granted there are many reasons for America's declining health, but it is now accepted that "sick building syndrome" is partly to blame, and VOCs contribute to that. New carpeting cannot outgas when rolled up, and does not do so in just a couple of weeks when rolled out. The process continues for months and even years at low levels. This also happens with some particleboard and vinyl flooring. Non-toxic sealants can be applied to seal in toxic vapors once materials are installed but it is always better to pay more to avoid them in the first place. Non-toxic or low-toxic alternatives exist that should be invested in to protect your health and the health of your family, especially children. You save on out-of-pocket health care costs. Wall-to-wall carpeting is a problem, especially in the bedroom, because it harbors dust, dust mites, mold and can never get fully clean. Choose alternative flooring with throw rugs that will last longer than cheaper carpeting. Remember, you need to replace carpeting two or three times over the life of a house. You save money in the long run and reduce health care costs when you choose healthy alternatives up front. Additional IAQ Issues There are other sources of poor indoor air, including dust mites, asbestos, pesticides and radon. These will be covered in more detail in the lecture but can be identified in a home inspection and rectified. Next month, we will discuss the Building Biology approach to new home and office construction. This approach saves money in the long run, maintains high resale value and provides a healthy and comfortable new home. For more information, contact Oram Miller of Environmental Design and Inspection Services, at 952-412-0781.
|
|
|