4 Types of Radon Mitigation Systems

passive suction ventilation system beneath house foundation

Radon isn't often talked about or though about, but it is a threat for homeowners and residents. If you haven't yet tested for radon, you should do so immediately. Based on the results of said test, consider looking into radon mitigation systems.

The purpose of a radon mitigation system is to decrease the amount of radon in the home. Radon is a gas that is odorless and tasteless, created from decomposing uranium found in water, soil, and rocks. Radon is the second leading cause of lung cancer.

This makes having a proper radon mitigation system important. Many people labor under the false belief that an air conditioning system may help with radon, but conditioned or cooled air is not necessarily decontaminated air. This article will go over various types of radon mitigation systems that could be installed in your home.

1. Active Suction

Radon mitigation systems that use active suction are often limited to homes that have a concrete slab basement or basements on a gradient because radon gas has a tendency to build up under the concrete of a basement foundation.

Eventually small cracks form in the concrete from normal wear and tear, and the built up gas escapes and enters the home.

The active suction system is named as such because it involves an electrical vent fan, an electrical monitoring system, and a vent pipe placed between sub-slab gravel that stretches up to a point above the roof on the outside of the home.

When the fan runs, it has just enough power to keep radon from gathering under the home. Remaining cracks in the basement concrete get sealed. This not only makes it so that the only point of exit for the trapped sub-slab radon is the exit vent of the system, but also decreases the loss of the conditioned air.

2. Passive Suction

These types of radon mitigation systems are typically installed when a house is being constructed. The home is built with differing pressures in various rooms and parts of the house. This is done so that you do not need an active trigger for ventilation, such as the electrical fan described above. The natural pressure differential is enough to encourage the flow of air in a specific direction.

A duct system is then installed to take advantage of that air flow and to guide the radon out and away from the home. Passive suction radon mitigation systems are only good in homes that have very low levels of radon. Passive suction also cannot be installed in older homes due to the specifics needs on a room-by-room basis.

3. Pressure Systems

Pressure systems are not so much systems as they are just an intervention on your part. Rather than relying on the conscious decisions of a builder or installer to create a duct system or a beneficial difference in pressure, this method involves you, the resident, to keep windows and doors closed in the lower sections of your home more often than they are open. Essentially you are creating pressure by having air forced in to the home. This pressure will prevent the radon gas from coming up through the foundation of the home.

While obviously the least expensive option due to the lack of hardware, only certain types of homes are truly ideal to flourish under this method. It is also important to know that it puts a large amount of ongoing responsibility on you, as opposed to technology.

4. Sub-membrane

This is another type of suction radon mitigation system. This is especially helpful in a home that has a crawlspace, even more so if the floor is dirt or loose gravel. The floor of the crawlspace is covered with a heavy plastic sheet. A channel is created, and eventually a fan and a pipe that leads outdoors are installed. The radon gas is flushed out of the home under the plastic sheet.

It's similar to the active system already described, with the notable difference being that instead of allowing the gas to become trapped or collected under a basement slab of concrete before venting, in this scenario your pre-vent collection area is the plastic sheet membrane.

Other Options

New emerging methods now exist, but they are still flawed and evolving. For example, heat recovery ventilators (HRV) as well as energy recovery ventilators (ERV) are viable methods of venting radon from your home, but the overall success is climate dependent. These systems work well where it is hot, but in areas with higher humidity, they encourage an excess of moisture and have been reported to cause serious mold problems.