Question – I am thinking about purchasing granite countertops for our kitchen and bathrooms, but I have been reading some horror stories about granite and radon. Now I read your web site, and you say not to be concerned. How can I be sure that the granite I’m chosing doesn’t emit radon? I am honestly very worried after reading about it online, but then you say it’s not true at all.

My Answer – Thanks for the question. The real issue is not whether granite emits radon. It does. Some types emit more than others. The question is whether this is a problem or not. The amount of radon emitted by granite is very small compared to the radon that is emitted by the earth beneath your house. Just look at the size difference. Does the amount of stone in your countertops come close tot eh amount of stone in the ground beneath your house? It’s not even close.

Radon seeps from the ground and it can become a problem when it gets trapped by your house. Your house acts like a hat, preventing the radon from rising up into the atmosphere. If a house has a radon problem, the cure is to ventilate the space beneath the basement slab or the crawlspace with a small fan, thus “untrapping” it. It does not take much air movement to rid the house of radon. When houses have radon problems, it’s because the enclosed crawlspace or basement trap it and don’t let it dissipate. Your kitchen is certainly not an enclosed space. It would be very hard for radon to build up in there to harmful levels. The fact that a kitchen is open to other rooms, doors open and close, exhaust fans run, etc. means that any radon is vented out and never can build up to a level even close to being harmful.

The bottom line is this. For your granite countertops to present a radon health issue, you would need much more granite than a typical kitchen would have, it would have to be a high emitting granite, you would need to keep the kitchen tightly sealed for long periods of time, and you would have to live in there, sleeping on the countertop, for years before this would be a real health issue.

The detractors of granite are the producers of other countertop materials. Every few years they trot out their videos showing the radon meter indicating elevated radon on the surface of the granite. But they unfairly omit the full facts, leaving the viewer with the impression that granite is dangerous. You never see them give radon readings elsewhere in the rooms. They put the meters right on the granite. It makes me wonder how people have lived in stone houses for so many years. No one worries about stone floors or fireplaces. This issue is simply a competitor taking unfair pot shots at a rival based on partial information that plays on people’s fears.

I hope that explains it for you. But if you are stilled worried, there are other countertop materials to choose from. Granite is very nice and, in reality, is no heath problem. But worry is unhealthy. So choose the material that does not worry you.

If you would like to read more articles about house and home design, please visit my other website, www.about-home-design.com.

There are two reasons for that. First is the cost. Traditional, all masonry fireplaces are very expensive to build. The entire chimney must be built of masonry and the tall column of cement blocks, bricks, and terra cotta flue liner is very expensive. Plus, a true masonry fireplace requires a foundation to carry the weight. That adds more cost. Pre-fab metal units have taken over the marketplace for cost alone. Some pre-fab fireplace companies are Heatilator, Majestic, and Heat-n-Glo. These fireplaces have some limitations on the size of the firebox opening. If I need a particularly large opening, I turn to Isokern. This is a fireplace that is made of a special type of concrete block system, but it does not require the full masonry flue. So it is a compromise between the design freedom of the traditional masonry fireplace and the cost benefits of the pre-fab units.

Wood-burning models of pre-fab fireplaces are readily available, but in spite of that, most of my clients choose to set these fireplaces up with gas logs for the sheer convenience of starting and stopping a fire whenever they want. Many people have grown tired of chopping and carrying wood, cleaning up the mess and bringing bugs into the house and give up the ambiance of a real wood fire in favor of the convenience of a gas log fire. These days, there are many very good choices of gas log sets that provide a realistic wood fire look. Because most of the heat goes up the flue, fireplaces are not energy efficient. They can actually draw more heat out of a house than they can provide. Fireplaces should be viewed as decorative elements in a house.

Some gas fireplaces require a vent pipe and others do not. The vented gas fireplaces give the most traditional look since they do not have to have glass doors on the firebox. But vented gas fireplaces must have the damper held open permanently according to the building code. This allows heated air from the house to continually escape up the flue twenty four hours a day. This is obviously an energy loss. Open fronted, vented fireplaces also use the air inside the house for combustion and can allow combusted air to return back into the house. People who have allergies or sensitivities to petroleum products could react negatively to this. For those people, a direct vent fireplace might be a better solution.

Direct vent fireplaces take outside air for the combustion and vent the combusted air back outside. No indoor air is used. No pollution is added to the indoor air. No heated house air escapes the house. They cost less initially because no chimney is required. A direct vent fireplace can add heat to the house, but not as efficiently as a gas furnace. The major objection to direct vent fireplaces is that a fixed glass panel covers the firebox. Sometimes people describe this as an aquarium look because of the glass. But there are decorative frames for the glass that make it look like a set of good glass doors.

All in all I would say that most of the fireplaces I design are gas log types with the exception of outdoor fireplaces. For those, wood-burning is still the preference. Of the indoor fireplaces, most are the vented variety primarily because of the appearance. People prefer the traditional open faced firebox. But in some situations, the direct vent type is the best choice, especially if finding a location for the flue and chimney is difficult or cost is a priority.

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I’ve been perplexed by this issue and I’ve found that it is very difficult to find dependable information on this subject. Part of the reason for this lack of good information is that no one really knows answers with any scientific foundation. I’ve been doing a lot of reading and based on that research, I’ve come to the following conclusions. As you read these, please keep in mind that I am also among the legions of mold non-experts who have voiced their opinions on the subject. But this information was taken from what I thought were reliable sources. Hopefully this will put the mold issue into perspective.

1. You can not eliminate mold in your house. It is always there. So the best recommendation is to control the moisture in the house by keeping the relative humidity between 30% and 60%. Mold needs moisture and it will grow when the relative humidity is above 60% to 65%. Surfaces that have condensation appear on them will be more prone to growing mold because condensation is 100% humidity, of course.
2. There are over 60,000 known types of mold. Only a few are known toxins. The huge majority of them are benign or their effects are unknown. And they live everywhere around us all the time.
3. Testing for mold has a limited value since nearly every test will show some mold. Even the spore count can be deceiving depending on the reproductive cycle of the mold. Some tests can show large releases only to be followed by extended periods of dormancy. Testing should be done on the outside of the house as a point of comparison. It is possible that similar levels of mold exist all around and the amount found in the crawlspace do not represent anything abnormal. Even the State of California Department of Health does not recommend testing for mold contamination because of the lack of standards for judging what is an acceptable quantity of mold! From what I’ve read, the only way to know if you have too much mold is if you can smell it or see it. Even then, the odds are highly in your favor that the mold you smell is not harmful since the vast majority of mold is not harmful.
4. Most molds produce volatile organic compounds (VOCs) that become airborne and smell musty. These are offensive, but are not thought to cause illness. Some molds, at certain times do produce toxic chemicals called mycotoxins. If inhaled in sufficient quantities, some people can get sick from these. But this is not an established risk for healthy people. It is more likely in people with weakened immune systems.
5. Molds can trigger asthma attacks or hay fever, but there is no proof that molds cause these ailments. The only cases of molds causing infections in humans are rare and only occur in people with a weakened immune system.
6. Mold can grow on any surface. Metals and other non-porous surfaces are just easier to keep clean than surfaces like wood or paper. However some metals, like copper and zinc form a fungicide when they oxidize. That is why better asphalt shingles are made with zinc granules in with the stone granules to prevent the fungus streaks you often see on roofs in the South. Copper or zinc ridge strips were often used for this purpose, too. But metal duct systems can be easily cleaned and disinfected.
7. Mold can germinate, or “bloom” in as little as twelve hours and start to grow in a day or two. So weekly monitoring is essentially useless. If the moisture is too high, mold will get ahead of you really fast.
8. There are tons of alarmist stories and law suits out there right now so it’s about impossible to sort out the truth. That’s because no one seems to really know the truth.
9. Lawsuits regarding mold almost always point to the builder unless there is some demonstrated neglect by the owners, such as allowing a leak to go unfixed. However, improper detailing can leave architects and engineers with a legal exposure, too. No matter the situation, it is very hard to determine fault with any accuracy since there are many sources of moisture entering a house and because of the lack of scientific data, the damage due to mold is hard to quantify. Still, many of the judgments awarded in mold lawsuits are based on sympathy for the homeowner and not actual facts like many fantastic lawsuits these days.
10. The longer a house is under construction prior to the roof going on and getting the house “dried in”, the more susceptible it will be to mold. Work should proceed expeditiously to let the house get dry as quickly as possible.
11. The greatest risk of mold growth actually occurs during the cooler months when the relative humidity remains above 90% for sustained periods. That would be a day like we had on Wednesday when everything seems to have condensation on it. I know it seems counter-intuitive, but during the high humidity, hot days in the summer, the relative humidity is actually lower than those damp days in the winter. This is because warm air can hold more grains of moisture and the surfaces are warmer and the dewpoint is not reached to cause condensation. Cooler surfaces cause condensation, not warmer ones.
12. The New York City Department of Health and Mental Hygiene Guidelines on Assessment and Remediation of Fungi in Indoor Environments (2002) is the most widely recognized guide for remediation.
13. One interesting thing I have learned is that mold will not grow on lumber with a moisture content below 20%. And even then, the wood must remain sufficiently wet for approximately seven days.
14. Your yard (and mine) is loaded with mold. Everyone’s is except maybe in Arizona. Even there the spores probably exist, just waiting for a little moisture.

The bottom line is this. Your builder should warrant the health of the house he is turning over to you. However, I don’t know that there is any way he can really certify this since there is no “standard” in the industry. So a measure of reasonableness is required. The mere presence of mold is not a cause for alarm. But a large and visible outbreak of mold needs to be dealt with in a level-headed way. A well-educated builder is the first step in preventing mold. Controlling moisture is the primary mission. If you do that, you will control mold in your house.

If you want another perspective on the validity of the mold health issue, you might find this article, The Mold Scare: Medical facts versus dubious myths, by Gailen D. Marshall Jr., the director of the Allergy & Clinical Immunology Division at The University of Texas Medical School-Houston interesting and enlightening.

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