Radon in granite building materials has never been considered a major source of radon in the home. Radon is found not only in granite but in cement, bricks and other stone building materials as well. But the amount of radium present in granite countertops and fireplaces rarely in themselves can contribute to elevated radon gas levels in a building.
Consider the huge surface area of all the soil and rocks below and around the foundation of a house in comparison to the stone building materials in the home. Radon rising into the home from the earth is almost always the major cause of high radon levels.
So what's all the buzz over radon in granite countertops?
First of all measuring radon with a hand held radiation device or Geiger Counters will not read only the presence of Radon gas, in your counter top. Geiger Counters read gamma rays which emanate from many different sources. Potassium and Thorium are two large sources in granite. Potassium is a very common element and is found in our bodies and in much of the food we eat. So up to 95% of clicks produced by a Geiger counter is often caused by Potassium. To read the level of radon from your countertop will take a more precise method.
Radon in granite could be illustrated by the heat produced by a candle burning in a room. If you put your hand over the top of the flame you can feel the heat. But will the candle ever heat the air in the room noticeably? No. Likewise with radon emanating form building materials, it is usually not a significant factor in the home's total radon level.
Radon gas levels are always in direct relation to the volume of the living space and the ventilation of home. So back to the candle, the effect on the air in the home is also dependent of these variables also.
So the reasonable course to take is to test your home for radon. If you what to experiment a bit do 3 or 4 tests. Since radon is heavier than air do 1 test in the basement. And another in the area where the countertop or fireplace is located. Then another one or two tests on the same floor of the as the granite material will help you to see if the major source of the radon gas in your home is coming from.
I seriously doubt you will have to rip out your countertop if you find a high radon level in your home. Sub-slab depressurization systems that remove the radon gas from below your home is very effective and relatively inexpensive solution for most buildings. This should be always the first course of action if your levels are higher on the lowest level of your home. Learn more about radon mitigation techniques here...
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