Radon Mitigation for Existing Homes

Active Soil Depressurization Systems (ASD)

Radon mitigation for existing homes is a crucial process aimed at reducing the levels of this naturally occurring radioactive gas within residential spaces. Radon, a colorless and odorless gas, can seep into buildings through cracks in the foundation, gaps in construction materials, or crawl spaces. Long-term exposure to elevated radon levels poses serious health risks, including an increased likelihood of lung cancer. Mitigation strategies for existing homes involve various techniques, such as sub-slab depressurization or sub-membrane depressurization systems, designed to create a barrier that prevents radon from entering living areas. These strategies are essential to safeguard the health and well-being of occupants by effectively reducing radon concentrations within the home environment.

Sub Slab Depressurization

A sub-slab depressurization radon mitigation system is a method used to reduce radon levels in buildings. Radon is a naturally occurring radioactive gas that can seep into homes and buildings through cracks in the foundation or gaps in construction materials. It’s a health hazard when accumulated in high concentrations.

The sub-slab depressurization system typically involves the following steps:

Assessment: Initially, radon levels are tested within the building to determine the extent of the problem.
Installation: PVC pipes are inserted through the floor slab or via a hole drilled into the concrete slab beneath the building. A fan is attached to the pipe to create a vacuum or suction beneath the building.
Extraction: The pipes extend from beneath the building and vent the radon gas to the outside, usually above the roofline. As the fan operates, it draws the radon gas from beneath the building, preventing it from entering the living spaces.
Sealing: To enhance the system’s effectiveness, potential entry points for radon, such as cracks and gaps in the foundation, are sealed to minimize radon infiltration.

This system creates a pressure difference between the soil beneath the building and the interior, preventing radon from entering the living areas and directing it safely outside where it disperses harmlessly into the atmosphere.

Sub-slab depressurization systems are considered one of the most effective ways to mitigate radon levels in buildings and can significantly reduce health risks associated with radon decay particle exposure.

Sub Membrane Depressurization

A sub-membrane depressurization radon mitigation system is another method used to reduce radon levels in buildings, particularly in structures with crawl spaces.

Here’s an overview of how this system typically works:

Assessment: Similar to other radon mitigation methods, an assessment of radon levels within the building is conducted.
Installation: A sub-membrane depressurization system involves laying a gas-permeable membrane (typically made of plastic sheeting or other similar materials) over the soil or gravel within the crawl space secured to the concrete footer walls. Perforated pipes or a network of pipes are placed under this membrane.
Extraction: A fan connected to these pipes creates suction or a vacuum under the membrane, pulling radon and other soil gases from the space beneath the building.
Ventilation: The radon gas and other soil gases drawn from beneath the membrane are then vented outside the building through a pipe or series of pipes, usually above the roofline.
Sealing: As with other radon mitigation methods, potential entry points for radon, such as cracks and gaps in the foundation or walls, are sealed to minimize radon infiltration.

The sub-membrane depressurization system aims to create a negative pressure barrier between the soil in the crawl space under the membrane and the building, preventing radon from entering living areas and directing it safely outside.

This method is particularly effective for structures with crawl spaces providing an efficient way to mitigate radon levels and reduce health risks associated with radon decay particles exposure in those environments.