Your house type will affect the kind of radon 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 radon 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 radon 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 radon 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.
