Intro to Mitigation
All Homes Can be Fixed
Reliable techniques exist for reducing radon levels in homes. Experience with radon mitigation systems has developed to the point that virtually any home can be fixed, either by a trained radon contractor, or in some cases, by homeowners who accomplish the repairs themselves. One out of 15 (6%) homes nationally may have elevated indoor radon levels that should be lower. The percentage of elevated homes in your state may be much higher. The only way to know a house is elevated is to test.
How do I treat radon?
Research by public and private agencies, years of extensive hands-on mitigation experience, and long-term follow-up studies on the durability of radon mitigation systems have formed a strong knowledge base of proven mitigation techniques for homes, schools, and commercial buildings. The techniques are straightforward and, for a typical single family residence, can be done in one day by a qualified contractor.
Radon reduction requires more than just sealing cracks in the foundation. In fact, caulking and sealing of foundation openings, on its own, has proven not to be a reliable or durable technique. However, sealing is done in conjunction with other mitigation steps.
Active soil depressurization (ASD) has proven to be a cost-effective and reliable technique for radon reduction, by collecting the radon from beneath the building before it can enter. The systems can be simple or complex, depending upon the design of the building. Operating costs of the fans are minor, due to their low power consumption (typically less than 90 watts per fan).
The system draws the radon-laden soil gas from beneath the foundation and exhausts it outside of the building, far enough away from windows and other openings that it will not reenter. The system typically consists of a plastic pipe connected to the soil through a hole in a slab floor, through a sump lid connection, or beneath a plastic sheet in a crawl space. Attached to the pipe is a quiet, continuously operating fan that discharges the radon outdoors.
The system design is a function of the construction of the home, rather than the radon concentrations in the home. A home with more than one foundation can present challenges to collecting the soil gas from under all portions of the building. However, trained mitigation contractors can sometimes connect multiple systems together so that only one fan system is required.
What is a radon mitigation system?
A radon mitigation system is any system or steps designed to reduce radon concentrations in the indoor air of a building.
The EPA recommends that you take action to reduce your home's indoor radon levels if your radon test result is 4 pCi/L or higher.
What can be done to reduce radon in a home?
Your house type will affect the kind of radon reduction system that will work best. Houses are generally categorized according to their foundation design. For example: basement, slab-on-grade (concrete poured at ground level), or crawlspace (a shallow unfinished space under the first floor). Some houses have more than one foundation design feature. For instance, it is common to have a basement under part of the house and to have a slab-on-grade or crawlspace under the rest of the house. In these situations a combination of radon reduction techniques may be needed to reduce radon levels to below 4 pCi/L.
There are several methods that a contractor can use to lower radon levels in your home. Some techniques prevent radon from entering your home while others reduce radon levels after it has entered. the EPA generally recommends methods that prevent the entry of radon.
In many cases, simple systems using underground pipes and an exhaust fan may be used to reduce radon. Such systems are called "sub-slab depressurization," and do not require major changes to your home. These systems remove radon gas from below the concrete floor and the foundation before it can enter the home. Similar systems can also be installed in houses with crawl spaces. Radon contractors use other methods that may also work in your home. The right system depends on the design of your home and other factors.
Sealing cracks and other openings in the floors and walls is a basic part of most approaches to radon reduction. Sealing does two things, it limits the flow of radon into your home and it reduces the loss of conditioned air, thereby making other radon reduction techniques more effective and cost-efficient. The EPA does not recommend the use of sealing alone to reduce radon because, by itself, sealing has not been shown to lower radon levels significantly or consistently. It is difficult to identify and permanently seal the places where radon is entering. Normal settling of your house opens new entry routes and reopens old ones.
Any information that you may have about the construction of your house could help your contractor choose the best system. Your contractor will perform a visual inspection of your house and design a system that is suitable. If this inspection fails to provide enough information, the contractor will need to perform diagnostic tests to help develop the best radon reduction system for your home. Whether diagnostic tests are needed is decided by details specific to your house, such as the foundation design, what kind of material is under your house, and by the contractor's experience with similar houses and similar radon test results.
How much does it cost to reduce radon in an existing home?
The cost of making repairs to reduce radon is influenced by the size and design of your home and other factors. Most homes can be fixed for about the same cost as other common home repairs, like painting or having a new hot water heater installed. The average cost for a contractor to lower radon levels in a home is about $1,200, although this can range from $800 to about $2,500. Your costs may vary depending on the size and design of your home and which radon reduction methods are needed.