Today’s topics are Moisture Problems & Radon Gas

My guest today are Mac Davis with MHD Construction and Jean Gibson, Vive President of Gibson Home Builders, Inc.

Mildew --The Problem
What is mildew? Mildew is a mold. A mold such as mildew can decompose cellulose and lignin, therefore ruining paper and cellulose fabrics that are not protected. Wood, paint, glue, and leather may be attacked by mildew also. Mildew mold secretes an enzyme that decomposes organic matter and uses it for growth and reproduction. High humidity is required to hydrate mildew cells and materials on which they can grow. Mildew is unsightly, produces an unpleasant odor, and often acts as an allergen that can create health problems.
What is necessary for mildew to grow? Mildew spores, or seed-like forms of mildew, exist almost everywhere. They will not grow and spread, however, unless certain conditions are met. There are many varieties of mildew, but generally the following conditions contribute to mildew growth:

1) Molds thrive on organic materials such as paper, leather, natural fibers or surfaces coated with the slightest amount of organic matter such as food or soil.
2) The optimal growth temperature range for molds is 77°F to 88°F (20°C to 30°C), though some growth may occur anywhere between 32°F to 95°F (0°C to 35°C).
3) Mildew requires moisture. The optimal growth range for mildew is 70 to 93 percent relative humidity (RH). RH would have to be below 62 percent to stop all chances for mold growth, although RH below 70 percent inhibits most mold growth. A lower RH delays spore germination of molds, reduces the rate of mold growth, and lowers the number of cells produced.
4) Molds are aerobic. That is, they require oxygen for growth.
5) Light is not required for mold growth. Mold growth can continue indefinitely without light.
6) Mold growth is promoted by a slightly acid condition.
7) Mold growth is inhibited by a variety of fungicides such as chlorinated phenols, copper napthenate or oleate. Coal tar creosote can be used on wood surfaces where paint is not to be used or where odor or appearance would not be objectionable. Ultra-violet radiation can kill mildew. Exposure to sunlight has been a mildew remedy since pre-air conditioning days.
Mold growth is slow to start and can take several months or seasons to get established. After growth begins, however, it is very rapid.

Identifying Mildew
Mildew on textiles, books, and other household materials will often be recognized by an unpleasant musty odor as well as by discoloration. Dirt on some hard surfaces such as paint, tile, or wood resembles the discoloration caused by mildew. To distinguish between dirt and the discoloration produced by mildew, put a few drops of household chlorine bleaching solution on the discolored surface. Mildew will be bleached within a minute or two, but most dirt will not bleach.
Stains on the exterior surface of buildings that appear below the shade line are usually a type of algae rather than mildew. However, algae often responds to the same types of removal treatment as mildew. In warm, humid environments, treatment of mildew outside a home will need to be repeated from time to time.

Preventing Mildew Growth
Since mildew spores are almost always present, the three best ways to control mildew growth are to eliminate the source of food, deprive the mildew of sufficient moisture, and/or to keep the temperature too low for fast mildew growth.
Keeping things clean. Many materials in homes provide a ready source of nutrients for mildew. Mildew can feed on natural fibers used in clothing and furnishings, paper materials that have not been treated, glues such as those sometimes used in book bindings, and materials in some grout. Some other materials, such as ceramic tile, glossy paint, and glass, do not support mildew growth when they are clean. However, the slightest amount of soil on their surface will supply the necessary nutrients for mildew growth. The organic residue of some soaps left on shower stalls and shower curtains provide the required nutrients for mildew growth. Smoke and volatile cooking oils also settle on walls and furnishings to provide a soil on which mildew will grow. Walls, closets, basements, clothing and other textiles where mildew is likely to grow should be kept clean.
Controlling the temperature. Since mildew thrives at temperatures between 77°F and 86°F, summer conditions will encourage mildew growth. Air conditioning will reduce the interior temperature of homes, but the temperature may not be uniformly low enough to stop mildew growth if the air is fairly humid. Areas within cabinets and closets or behind draperies may be warmer, and humidity will be trapped unless the doors are louvered or left ajar.
Controlling moisture in the air. Since a high relative humidity is required for mildew growth, we need to understand what RH is and how it is related to temperature. Technically, RH is the ratio of the partial pressure of the actual water vapor in the air to the pressure of totally saturated air at the same temperature.
Warm air can hold more moisture than cool air. For example, air at 80°F can hold twice as much moisture as air at 60°F. If air in a house at 60°F and saturated with moisture (100 percent RH) is heated to 80°F without a change in moisture, the RH would then be about 50 percent. Both situations would prevent mildew growth: 60°F is too cool for fast mildew growth even at 100 percent RH, and 50 percent RH would be too dry at 80°F.

Managing Moisture in the Home
An ounce of prevention is worth a pound of cure, and with mildew problems, this is especially true. Water vapor moves quickly from a high humidity area to a low humidity area. Think about how rapidly condensation forms on a jar taken from a refrigerator.
Moisture can become trapped in enclosed areas when humidity is sometimes high and sometimes low. In such areas, plastic wrap is not recommended for storing mildew-sensitive materials. Louvered doors and wire closet shelving help promote circulation of air. You may have observed mildew growing behind large pieces of furniture that are placed too close to a wall. Where there is a potential moisture problem, solid closet doors and drawers should be left ajar to encourage air circulation. If a closet, cabinet or drawer space reaches the point of smelling musty, it and its contents should be cleaned and thoroughly dried.

Indoor Moisture Production
Moisture accumulates inside a home from normal household activities: breathing, bathing, cooking and cleaning. A family of four at home for 12 hours a day can produce about 6 pints of water as moisture by respiration. Each shower bath would add another half pint of water directly to the air, and moisture left in the shower stall and on towels would add even more. A bath in a tub would add a little less moisture. Cooking might add another two to three pints. Washing clothes, dishes, and floors would also add more moisture. Ways to reduce some of the moisture from these sources can come from common sense, such as cooking with covers on pans.

Managing Moisture from Outside
The environment in Florida and many coastal areas of the country is nearly always humid and much of the year quite warm. The temperature and humidity levels of outside air are high enough to cause mildew to flourish outside under leaves and in shady places. When this warm, humid air enters a house, it has the capacity to support mildew growth indoors as well. For example, if 85°F air outside with 60 percent or higher RH enters a house and is cooled by walls and furnishings without air conditioning to 80°F, the RH will be 70 percent or higher. These conditions are right for mildew growth indoors, too. Lowering the temperatures only will further increase the relative humidity. Ventilation during warm, humid periods, even at night or early morning when outside temperatures are low, can lead to mildew conditions.
Vapor pressure. Vapor pressure moves moisture through cracks, down the fireplace chimney, and through doors and windows when they are open. Vapor pressure can move moisture through many materials. Once moisture gets into a house, it continues moving into closets, cabinets, and drawers. Once moisture is diffused into wood or other materials, it is very difficult to drive out.
Ventilation. The function of ventilation in inhibiting mildew growth is to replace moist indoor air with dry air. Open windows and doors or exhaust fans can serve this purpose if the outside air holds less moisture than the inside air. When trying to control moisture during the air conditioning season, windows and doors probably should not be opened at night unless the nighttime low temperature is at least 15°F lower than the air conditioning thermostat setting. The dew point temperature should be below 55°F or 60°F. As much as 7 or 8 pints of excess moisture can be brought into a house every hour. An air conditioner would have to work much harder the following day to remove the moisture.
In a home, moisture also gets into closets, cabinets, and drawers during humid, non-air conditioning periods. The moisture is released very slowly when room air dries out.
Infiltration of air. A new, tightly constructed house can be expected to have some leaks around windows, doors, vents and other joints that will permit one/half air change per hour. On a humid, summer day as much as 20 gallons of moisture can come into a house through infiltration. Older homes sometimes have as many as 2 air changes per hour. In colder climates, weatherstripping is suggested to reduce the infiltration of cold air. In warm, humid climates, where air conditioning is used much of the year, weatherstripping is suggested to reduce the infiltration of moisture, even more than to keep out heat in the summer or to keep it in during the winter.

Air Treatment
Air Conditioners. Air conditioners remove moisture from the air as the air is cooled. Air is blown over cooling coils, and since cool air can't hold as much moisture, some of this moisture condenses on the coils and runs to a drain. The heat absorbed from the air by the air conditioner is carried by a refrigerant to coils outside the house where the heat is released.
Since moist air conditioners are designed to cool more than to dehumidify, they do not dehumidify effectively enough in Florida during humid periods, which last from May through October.
The longer an air conditioner is operated, the greater the amount of moisture that will be removed. An air conditioner unit too large for the area it cools might not operate long enough to remove enough moisture. Even though the home is cool, enough moisture can remain to produce mildew in areas with little air movement. Unfortunately, energy efficient air conditioners may not reduce humidity effectively enough for homes in warm, humid climates.
When air conditioning during humid weather, do not set the air conditioner fan to run continuously. This will cause moisture just removed by the cooling coils to be put back into the air, therefore, keeping the air more humid.
Dehumidifiers. Where no air conditioning is provided, a dehumidifier can be used if properly sized for the area. When using a dehumidifier, windows and doors must be kept closed. A dehumidifier collects moisture from the air in much the same manner an air conditioner does. However, a dehumidifier has both the heating and cooling coils inside, so there is little temperature change in the air, and moisture removed is either collected in a container that must be emptied periodically or through a hose that runs into a drain. Collector pans can become a place for mold/mildew to grow if not cleaned and cared for properly.
Heating. In some closets or basements that are damp and cool, mildew growth may be inhibited by adding heat. As the air warms, its capacity to hold moisture increases. For example, air at 75°F and 75 percent RH can be heated to 85°F and the humidity will be less than 60 percent, low enough to slow mildew growth. If the problem area is large, such as a basement, an electric space heater can be used. NOTE: Gas and kerosene heaters add considerable moisture, so cannot be recommended for this purpose. A low wattage light bulb can do the job in the closet. Place the light bulb away from clothing or anything else that might ignite. Strip heaters designed especially for use in closets are available. For safety purposes, follow instructions very carefully.
Desiccants. In small, enclosed areas, where temperature and humidity cannot be controlled by air conditioning or dehumidification, desiccants can be used. Desiccants are materials such as silica gel or alumina that absorb up to half of their weight in moisture. Place an open container on the floor or a shelf of a closet that can be tightly closed. Once a desiccant becomes saturated it can still feel dry, but will remove no more moisture. To be used again, these desiccants must be heated in a vented oven at 300°F for several hours. They will then be dry and can be cooled and replaced in the closet to continue removing moisture.
Calcium chloride granules are also desiccants and can be used to remove excess moisture from an enclosed area. Granular calcium chloride can absorb and hold moisture equal to several times its weight. As it absorbs moisture, it liquifies and cannot be reused. The granules should be placed on a screen over a container that can catch the liquid as it forms. Calcium chloride will damage fabrics if it comes in contact with them. Calcium chloride is sometimes combined with other materials to keep it from liquefying as it absorbs moisture. Follow package instructions when using.

Chemical Mildew Inhibitors
There is no true mildewcide -- no product that will kill mildew and guarantee it will not return. Chemical mildew inhibitors should be used with caution, as they are toxic to people and animals.
Cleaning agents that claim to remove mildew most often have a chlorine component. Chlorine both kills mildew and bleaches the darkened mildew filament. However, when such products are used, some scrubbing and rinsing are required to remove the mildew and soil residue. Otherwise, as soon as humidity and temperature conditions are right, mildew will use the residue as a substrate to grow on. A new supply of mildew spores is always floating in the air waiting for the right conditions. Commercial fungicidal products in pressurized cans provide some mildew protection. Check the label on the container to see what it claims to do and for instruction on how to use it safely and effectively.

Protective Sprays
Water-repellent and soil-resistant spray treatments inhibit mildew growth by reducing moisture or food available. Carefully read instructions on the label to understand the claims made and to know how to use the product safely and productively.

Cold Weather Mildew Problems
Areas of Florida that have periods of very cold weather can be exposed to winter conditions that lead to mildew problems. Mildew in moderate climates is usually related to tight construction and indoor moisture production in cold weather. Without an interior vapor seal, moisture produced indoors during cold weather can penetrate walls and condense. Later, when outdoor temperatures are higher, mildew and other organisms can destroy studs in the walls. Occasional ventilation when outside air is cool and dry will protect against this cold weather/high humidity condition.
Basement mildew in moderate climates often starts in the spring when windows in a home are opened to air outside the house. Temperature on the floor and behind books and curtains in basements can still be below the dew point temperature. The relative humidity in these areas becomes high enough for mildew to grow. Apply heat as described earlier to provide protection from this potential mildew problem.

What are molds?
Molds are tiny microscopic organisms that digest organic matter and reproduce by releasing spores. Molds are a type of fungi and there are over 100,000 species. In nature, mold helps decompose or break-down leaves, wood and other plant debris. Molds become a problem when they go where they are not wanted and digest materials such as our homes.

What makes molds grow in my home?
Mold enters your home as tiny spores. The spores need moisture to begin growing, digesting and destroying. Molds can grow on almost any surface, including; wood, ceiling tiles, wallpaper, paints, carpet, sheet rock, and insulation. The mold grows best when there is lots of moisture from a leaky roof, high humidity, or flood. There is no way to get rid of all molds and mold spores from your home. But you can control mold growth by keeping your home dry.

Can I be exposed to mold?
When molds are disturbed, they release spores into the air. You can be exposed by breathing air containing these mold spores. You can also be exposed through touching moldy items, eating moldy food or accidental hand to mouth contact.

Do molds affect my health?
Most molds do not harm healthy people. But people who have allergies or asthma may be more sensitive to molds. Sensitive people may experience skin rash, running nose, eye irritation, cough, nasal congestion, aggravation of asthma or difficulty breathing. People with an immune suppression or underlying lung disease, may be at increased risk for infections from molds.

When is mold a problem?
You know you have mold when you smell the "musty" odor or see small black or white specks along your damp bathroom or basement walls. Some mold may be hidden growing behind wall coverings or ceiling tiles. Even dry, dead mold can cause health problems, so always take precautions when you suspect mold.

Mold is often found in areas where water has damaged building materials and furniture after flooding or plumbing leaks. Mold can also be found growing along walls where warm moist air condenses on cooler wall surfaces, such as inside cold exterior walls, behind dressers, headboards, and in closets where articles are stored against walls. Mold often grows in rooms with both high water use and humidity, such as kitchens, bathrooms, laundry rooms, and basements. If you notice mold or know of water damaged areas in your home, it is time to take action to control its growth.

When should I sample for mold?
You don’t need to sample for mold because in most cases you can see or smell mold. Even a clean, dry house will have some mold spores, but not enough to cause health problems. If you smell mold it may be hidden behind wallpaper, in the walls or ceiling or under the carpet. If you suspect you have hidden mold be very careful when you investigate, protect yourself from exposure in the same manner as you would for a clean- up. See clean-up chart below:

Can I control mold growth in my home?
Yes you can. Dry out the House and fix any moisture problems in your home:
• Stop water leaks, repair leaky roofs and plumbing. Keep water away from concrete slabs and basement walls.
• Open windows and doors to increase air flow in your home, especially along the inside of exterior walls. Use a fan if there are no windows available.
• Make sure that warm air flows into all areas of the home. Move large objects a few inches away from the inside of exterior walls to increase air circulation.
• Install and use exhaust fans in bathrooms, kitchens, and laundry rooms.
• Ventilate and insulate attic and crawl spaces. Use heavy plastic to cover earth floors in crawl spaces.
• Clean and dry water damaged carpets, clothing, bedding, and upholstered furniture within 24 to 48 hours, or consider removing and replacing damaged furnishings.
• Vacuum and clean your home regularly to remove mold spores.
• Check around your windows for signs of condensation and water droplets. Wipe them up right away so mold can’t start to grow.

What cleans mold?
Clean up mold and take care of the problem by keeping your home dry and keeping mold out.
Act fast! Mold damages your home as it grows. Clean it up as soon as possible.

Size the moldy area Decide if you have a large or small area of mold. A small area is less then about ten square feet, or a patch three feet by three feet square. To clean a small area, follow the advice below. You may use a cotton-face mask for protection.
If you have a lot of mold damage (more then ten square feet) consider hiring a cleaning professional. If the moldy area has been contaminated by sewage or is in hidden places hire a professional. To find a professional, check under "Fire and
Water Damage Restoration" in your Yellow Pages. If you decide to clean up on your own, follow the guidance below.

Use protection Wear goggles, gloves, and breathing protection while working in the area. For large consolidated areas of mold growth, you should wear an Occupational Safety and
Health Administration (OSHA) approved particle mask.

Seal the area Seal off area from the rest of your home. Cover heat registers or ventilation ducts/grills. Open a window before you start to clean up.

Remove items Remove all your furnishings to a mold-free area. Clean the surrounding moldy area then follow cleaning directions below for the items you removed and the new space.

Bag moldy trash Bag all moldy materials and tie off the top of the bag. Bring them outdoors and place
in your garbage container right away.

Scrub surfaces Scrub hard surfaces:
• First wash with a mild detergent solution, such as laundry detergent and warm water. Allow to dry.
• (Optional step) Then wipe with a solution of ¼ cup bleach to one quart of water. Wait 20 minutes and repeat. Wait another 20 minutes.
• Last apply a borate-based detergent solution and don’t rinse. This will help prevent mold from growing again. A borate-based laundry or dish washer detergent has “borate” listed on the ingredients label.

Clean and wash Give the entire area a good cleaning, vacuum floors, and wash any exposed bedding
or clothing.

Monitor Check regularly to make sure mold has not returned area.

What cleans-up moldy furniture?
How to clean your moldy furniture depends on how it reacts to water. See chart below:

Reaction to Water Items Recommendations
Doesn’t absorb water and is washable
Wood, metal, plastic, glass, and ceramics objects.
Wipe with a solution of lukewarm water and laundry detergent.
Absorbs water and is washable Clothes and bedding.
Wash in laundry.
Absorbs water but not washable Beds, sofas and other furniture.

These items may have to be discarded. Or, try to save by vacuuming well and allowing to air out. If there is no odor it may be okay. Mold can come back, so watch for any mold growth or mold related health problems. Discard the item if you suspect mold is growing inside or outside the item.

Should I paint over mold?
No. Don’t paint or caulk over mold. The mold will grow under the paint and the paint will peel.

Radon Gas

Radon Myths
MYTH: Scientists are not sure that radon really is a problem.
FACT: Although some scientists dispute the precise number of deaths due to radon, all the major health organizations (like the Centers for Disease Control and Prevention, the American Lung Association and the American Medical Association) agree with estimates that radon causes thousands of preventable lung cancer deaths every year. This is especially true among smokers, since the risk to smokers is much greater than to non-smokers.
MYTH: Radon testing is difficult, time-consuming and expensive.
FACT: Radon testing is easy. You can test your home yourself or hire a qualified radon test company. Either approach takes only a small amount of time and effort.
MYTH: Radon testing devices are not reliable and are difficult to find.
FACT: Reliable testing devices are available from qualified radon testers and companies. Reliable testing devices are also available by phone or mail-order, and can be purchased in hardware stores and other retail outlets. Call your state radon office for help in identifying radon testing companies.
MYTH: Homes with radon problems can't be fixed.
FACT: There are simple solutions to radon problems in homes. Hundreds of thousands of homeowners have already fixed radon problems in their homes. Radon levels can be readily lowered for $800 to $2,500 (with an average cost of $1,200).. Call your state radon office for help in identifying qualified mitigation contractors.
MYTH: Radon affects only certain kinds of homes.
FACT: House construction can affect radon levels. However, radon can be a problem in homes of all types: old homes, new homes, drafty homes, insulated homes, homes with basements, and homes without basements. Local geology, construction materials, and how the home was built are among the factors that can affect radon levels in homes.
MYTH: Radon is only a problem in certain parts of the country.
FACT: High radon levels have been found in every state. Radon problems do vary from area to area, but the only way to know your radon level is to test.
MYTH: A neighbor's test result is a good indication of whether your home has a problem.
FACT: It's not. Radon levels can vary greatly from home to home. The only way to know if your home has a radon problem is to test it.
MYTH: Everyone should test their water for radon.
FACT: Although radon gets into some homes through water, it is important to first test the air in the home for radon. If your water comes from a public water supply that uses ground water, call your water supplier. If high radon levels are found and the home has a private well, call the Safe Drinking Water Hotline at 1 800-426-4791 for information on testing your water.
MYTH: It's difficult to sell homes where radon problems have been discovered.
FACT: Where radon problems have been fixed, home sales have not been blocked or frustrated. The added protection is some times a good selling point.
MYTH: I've lived in my home for so long, it doesn't make sense to take action now.
FACT: You will reduce your risk of lung cancer when you reduce radon levels, even if you've lived with a radon problem for a long time.
MYTH: Short-term tests can't be used for making a decision about whether to fix your home.
FACT: A short-term test, followed by a second short-term test* can be used to decide whether to fix your home. However, the closer the average of your two short-term tests is to 4 pCi/L, the less certain you can be about whether your year-round average is above or below that level. Keep in mind that radon levels below 4 pCi/L still pose some risk. Radon levels can be reduced in most homes to 2 pCi/L or below.

Radon is a cancer-causing, radioactive gas.
You can't see radon. And you can't smell it or taste it. But it may be a problem in your home.
Radon is estimated to cause many thousands of deaths each year. That's because when you breathe air containing radon, you can get lung cancer. In fact, the Surgeon General has warned that radon is the second leading cause of lung cancer in the United States today. Only smoking causes more lung cancer deaths. If you smoke and your home has high radon levels, your risk of lung cancer is especially high.
Radon can be found all over the U.S.
Radon comes from the natural (radioactive) breakdown of uranium in soil, rock and water and gets into the air you breathe. Radon can be found all over the U.S. It can get into any type of building - homes, offices, and schools - and result in a high indoor radon level. But you and your family are most likely to get your greatest exposure at home, where you spend most of your time.
You should test for radon.
Testing is the only way to know if you and your family are at risk from radon. EPA and the Surgeon General recommend testing all homes below the third floor for radon. EPA also recommends testing in schools.
Testing is inexpensive and easy - it should only take a few minutes of your time. Millions of Americans have already tested their homes for radon (see How to Test Your Home).
You can fix a radon problem.
Radon reduction systems work and they are not too costly. Some radon reduction systems can reduce radon levels in your home by up to 99%. Even very high levels can be reduced to acceptable levels.
New homes can be built with radon-resistant features.
Radon-resistant construction techniques can be effective in preventing radon entry. When installed properly and completely, these simple and inexpensive techniques can help reduce indoor radon levels in homes. In addition, installing them at the time of construction makes it easier and less expensive to reduce radon levels further if these passive techniques don't reduce radon levels to below 4 pCi/L. Every new home should be tested after occupancy, even if it was built radon-resistant. If radon levels are still in excess of 4 pCi/L, the passive system should be activated by having a qualified mitigator install a vent fan. For more explanation of radon resistant construction techniques, refer to EPA publication, Building Radon Out: A Step-by-Step Guide on How to Build Radon-Resistant Homes (see EPA Publications).

How Does Radon Get Into Your Home?
Any home may have a radon problem
Radon is a radioactive gas. It comes from the natural decay of uranium that is found in nearly all soils. It typically moves up through the ground to the air above and into your home through cracks and other holes in the foundation. Your home traps radon inside, where it can build up. Any home may have a radon problem. This means new and old homes, well-sealed and drafty homes, and homes with or without basements.
Radon from soil gas is the main cause of radon problems. Sometimes radon enters the home through well water (see "Radon in Water" below). In a small number of homes, the building materials can give off radon, too. However, building materials rarely cause radon problems by themselves.

Nearly 1 out of every 15 homes in the U.S. is estimated to have elevated radon levels. Elevated levels of radon gas have been found in homes in your state. Contact your state radon office for general information about radon in your area. While radon problems may be more common in some areas, any home may have a problem. The only way to know about your home is to test.

How to Test Your Home
You can't see radon, but it's not hard to find out if you have a radon problem in your home. All you need to do is test for radon. Testing is easy and should only take a few minutes of your time.
The amount of radon in the air is measured in "picoCuries per liter of air," or "pCi/L." Sometimes test results are expressed in Working Levels (WL) rather than picoCuries per liter (pCi/L) (4 pCi/L equals to 0.016 WL). There are many kinds of low-cost "do-it-yourself" radon test kits you can get through the mail and in hardware stores and other retail outlets. If you prefer, or if you are buying or selling a home, you can hire a qualified tester to do the testing for you. You should first contact your state radon office about obtaining a list of qualified testers. You can also contact a private radon proficiency program for lists of privately certified radon professionals serving your area. For links and information, visit www.epa.gov/radon/radontest.html .
There are Two General Ways to Test for Radon:
SHORT-TERM TESTING:
The quickest way to test is with short-term tests. Short-term tests remain in your home for two days to 90 days, depending on the device. "Charcoal canisters," "alpha track," "electret ion chamber," "continuous monitors," and "charcoal liquid scintillation" detectors are most commonly used for short-term testing. Because radon levels tend to vary from day to day and season to season, a short-term test is less likely than a long-term test to tell you your year-round average radon level. If you need results quickly, however, a short-term test followed by a second short-term test may be used to decide whether to fix your home (see Home Sales).
How To Use a Test Kit:
Testing is easy and should only take a few minutes of your time.
Follow the instructions that come with your test kit. If you are doing a short-term test, close your windows and outside doors and keep them closed as much as possible during the test. Heating and air-conditioning system fans that re-circulate air may be operated. Do not operate fans or other machines which bring in air from outside. Fans that are part of a radon-reduction system or small exhaust fans operating only for short periods of time may run during the test. If you are doing a short-term test lasting just 2 or 3 days, be sure to close your windows and outside doors at least 12 hours before beginning the test, too. You should not conduct short-term tests lasting just 2 or 3 days during unusually severe storms or periods of unusually high winds. The test kit should be placed in the lowest lived-in level of the home (for example, the basement if it is frequently used, otherwise the first floor). It should be put in a room that is used regularly (like a living room, playroom, den or bedroom) but not your kitchen or bathroom. Place the kit at least 20 inches above the floor in a location where it won't be disturbed - away from drafts, high heat, high humidity, and exterior walls. Leave the kit in place for as long as the package says. Once you've finished the test, reseal the package and send it to the lab specified on the package right away for analysis. You should receive your test results within a few weeks.
LONG-TERM TESTING:
Long-term tests remain in your home for more than 90 days. "Alpha track" and "electret" detectors are commonly used for this type of testing. A long-term test will give you a reading that is more likely to tell you your home's year-round average radon level than a short-term test.
EPA Recommends the Following Testing Steps:
Step 1. Take a short-term test. If your result is 4 pCi/L or higher take a follow-up test (Step 2) to be sure.
Step 2. Follow up with either a long-term test or a second short-term test:
8) For a better understanding of your year-round average radon level, take a long-term test.
9) If you need results quickly, take a second short-term test.
The higher your initial short-term test result, the more certain you can be that you should take a short-term rather than a long-term follow up test. If your first short-term test result is more than twice EPA's 4 pCi/L action level, you should take a second short-term test immediately.
Step 3. If you followed up with a long-term test: Fix your home if your long-term test result is 4 pCi/L or more. If you followed up with a second short-term test: The higher your short-term results, the more certain you can be that you should fix your home. Consider fixing your home if the average of your first and second test is 4 pCi/L or higher.

What Your Test Results Mean
Test your home now and save your results. If you find high radon levels, fix your home before you decide to sell it.
The average indoor radon level is estimated to be about 1.3 pCi/L, and about 0.4 pCi/L of radon is normally found in the outside air. The U.S. Congress has set a long-term goal that indoor radon levels be no more than outdoor levels. While this goal is not yet technologically achievable in all cases, most homes today can be reduced to 2 pCi/L or below.
Sometimes short-term tests are less definitive about whether or not your home is above 4 pCi/L. This can happen when your results are close to 4 pCi/L. For example, if the average of your two short-term test results is 4.1 pCi/L, there is about a 50% chance that your year-round average is somewhat below 4 pCi/L. However, EPA believes that any radon exposure carries some risk - no level of radon is safe. Even radon levels below 4 pCi/L pose some risk, and you can reduce your risk of lung cancer by lowering your radon level.
If your living patterns change and you begin occupying a lower level of your home (such as a basement) you should retest your home on that level.
Even if your test result is below 4 pCi/L, you may want to test again sometime in the future.

Radon In Water

There are two main sources for the radon in your home's indoor air, the soil and the water supply. Compared to radon entering the home through water, radon entering your home through the soil is usually a much larger risk.
The radon in your water supply poses an inhalation risk and an ingestion risk. Research has shown that your risk of lung cancer from breathing radon in air is much larger than your risk of stomach cancer from swallowing water with radon in it. Most of your risk from radon in water comes from radon released into the air when water is used for showering and other household purposes.
Radon in your home's water is not usually a problem when its source is surface water. A radon in water problem is more likely when its source is ground water, e.g. a private well or a public water supply system that uses ground water. If you are concerned that radon may be entering your home through the water and your water comes from a public water supply, contact your water supplier.
If you've tested your private well and have a radon in water problem, it can be fixed. Your home's water supply can be treated in two ways. Point-of-entry treatment can effectively remove radon from the water before it enters your home. Point-of-use treatment devices remove radon from your water at the tap, but only treat a small portion of the water you use and are not effective in reducing the risk from breathing radon released into the air from all water used in the home.
For more information, call EPA's Drinking Water Hotline at (800) 426-4791 or visit www.epa.gov/safewater/radon.html If your water comes from a private well, you can also contact your state radon office.

How to Lower the Radon Levels in Your Home
Since there is no known safe level of radon, there can always be some risk. But the risk can be reduced by lowering the radon level in your home.
There are several proven methods to reduce radon in your home, but the one primarily used is a vent pipe system and fan, which pulls radon from beneath the house and vents it to the outside. This system, known as a soil suction radon reduction system, does not require major changes to your home. Sealing foundation cracks and other openings makes this kind of system more effective and cost-efficient. Similar systems can also be installed in houses with crawl spaces. Radon contractors can use other methods that may also work in your home. The right system depends on the design of your home and other factors.

Ways to reduce radon in your home are discussed in EPA's "Consumer's Guide to Radon Reduction." You can get a copy from your state radon office.
The cost of reducing radon in your home depends on how your home was built and the extent of the radon problem. Most homes can be fixed for about the same cost as other common home repairs. The average house costs about $1,200 for a contractor to fix, although this can range from about $800 to about $2,500. The cost is much less if a passive system was installed during construction.

Radon publications in print can be downloaded at www.epa.gov/radon/pubs