Does Radon Sealer Really Work?

Should radon sealer be used to remediate an indoor radon problem? The answer is: Maybe. It depends on how radon is entering the building and the kind of radon sealer you plan to use.

Radon sealer basically falls into 2 categories:
  1. Does Radon Sealer Really Work?The most common radon sealers are urethane based caulks. These radon sealers are used by mitigators to fill large openings in concrete walls and floors. Some of the openings that this kind of radon sealer would be used for include; cracks, floor/wall joints and gaps around utility penetrations. Never use silicon caulk as a radon sealer.

  2. Does Radon Sealer Really Work?The second category of radon sealer is the penetrating concrete sealer. This kind of radon sealer is sprayed onto a bare concrete wall or floor. It works by penetrating the concrete and reacting with the calcium hydroxide in the concrete, turning it into calcium silicate hydrate. This effectively seals the concrete from water vapor and significantly slows radon that may be diffusing through the concrete walls or floor. There also seems to be some anecdotal evidence that these types of radon sealers may also reduce radon gas emanating from the concrete itself.

So what does all this mean? Can radon sealers be used to significantly lower indoor radon concentrations? US EPA says "Sealing cracks and other openings in the foundation is a basic part of most approaches to radon reduction". However, EPA goes on further to say; "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".

This means that you should use urethane radon sealers on cracks and other openings. These radon sealers, however, must be used in conjunction with other mitigation methods such as an active soil depressurization system (pipe and fan system).

On the other hand, passive diffusion contributes very little (less than 10%) to indoor radon concentrations in most US homes. Also, radon emanating from building materials is rarely a problem in the USA. Therefore, using concrete penetrating radon sealers will, in most cases, be ineffective in lowering indoor radon concentrations in most US homes. (Unless of course your main source is from emanation or passive diffusion).

To get more help choosing the right radon test kits for your home use our Radon Testing Wizard . Or if you know which test you need you can go directly to the order page.

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