The EPA recommends a Standard Practice for Installing Radon Mitigation Systems in Existing Low-Rise Residential Buildings. This is a voluntary, consensus-based standard that was developed and issued by the American Society for Testing and Materials International, and is identified as ASTM E-2121.
When talking with a contractor about your mitigation alternatives, insure they follow the recommended standard set forth by the EPA.
Many General Contractors are building the mitigation right into the new construction, “just in case”. If you’re building a new home, it may be wise to inquire about this, as it may save you money down the road. Compare a system put in at time of construction to one put in 5 or 10 years later. It may just be money in your pocket.
The basic concept behind radon mitigation is redirecting the radon gas before it gets into the home. By intercepting the gas before it enters the home, there is a much lower risk to the occupants of the home.
There are several methods used as a mitigation for high radon levels.
The first is also the most used form of remediation.
Whether it is a slab, crawlspace or basement will dictate for the most part how much it’s going to cost.
√ Sub-Slab Ventilation.
Pipes are inserted into drilled penetrations in the slab. These pipes are then connected to a fan which draws the gas outside, usually through the roof.
√ Block Wall Ventilation.
Positive pressure- forcing air into the hollow block walls or negative pressure- using an exhaust fan to remove the radon can be used as a mitigating method.
√ Sealing penetrations.
Penetrations, cracks and voids in floors and walls are access points that radon readily passes through. Sealing is not a reliable method used alone.
√ Covering exposed earth under the home.
Covering a crawlspace floor with an impermeable material will help lower radon levels. As with all of these methods, proper application technique will determine its efficiency.
√ Drain-tile suction.
A perimeter drain is installed at the footing of the foundation. A fan is used to apply a negative pressure which draws radon away from the surrounding soil.
√ Replacement air.
Fresh air make up for combustion appliances (furnaces, gas water heaters) can help reduce the negative pressure induced in the home while running these systems.
√ Forced ventilation.
This method uses fans to exchange the indoor air multiple times per day. This not a viable method in climates where such temperature ranges exist. However a heat recovery system can reduce the wasted energy.
The only way to accurately determine the cost to you is to have a company dealing with radon mitigation give you an on-site estimate.
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