How Sub Slab Depressurization Works
Sub slab depressurization (SSD) is the most widely used and effective method for reducing radon gas in homes with concrete slab foundations. The system works by creating a zone of negative pressure beneath your home's foundation slab. A hole is cored through the concrete, and PVC piping is inserted into the aggregate or soil beneath. A specialized radon fan connected to the piping generates continuous suction, pulling radon-laden air from beneath the slab and venting it safely above the roofline where it dissipates harmlessly into the atmosphere.
This negative pressure field prevents radon from being drawn into your home through the natural stack effect that normally pulls soil gases indoors. Instead of radon seeping up through foundation cracks, expansion joints, and porous concrete, the SSD system intercepts it below the slab and redirects it safely outdoors. The result is a dramatic reduction in indoor radon levels, typically achieving 90% or greater reduction from pre-mitigation concentrations.
Why SSD Is the Gold Standard for Radon Reduction
The EPA and leading radon professionals across the country recognize sub slab depressurization as the most effective technique for reducing indoor radon levels. SSD systems consistently reduce radon levels by 90% or more, frequently bringing concentrations from well above 4 pCi/L to below 1 pCi/L. No other radon mitigation method achieves such reliable and dramatic results across such a wide range of home types and soil conditions.
In Billings, MT, where homes are commonly built on concrete slab foundations over granular fill material, SSD systems perform exceptionally well. The permeable aggregate layer beneath most slabs allows the suction field to extend broadly, often enabling a single suction point to depressurize the soil beneath an entire home. This means effective protection with a simple, low-maintenance system that runs quietly in the background around the clock.
Suitable for All Foundation Types
While sub slab depressurization is most straightforward to install in homes with standard slab-on-grade or basement foundations, the technique can be adapted for virtually any foundation type found in the Billings area. For homes with full basements, suction points are placed through the basement floor slab. For slab-on-grade construction, piping can be routed through interior walls, closets, or along the exterior of the home to reach above the roofline.
Homes with crawl spaces can benefit from a related approach called sub-membrane depressurization, where a heavy-duty polyethylene membrane is sealed over the crawl space floor and suction is applied beneath it. For homes with combination foundations, our team designs integrated systems that address radon entry from every section. Regardless of your foundation type, our licensed and insured technicians have the expertise to design an SSD solution that works for your specific situation.
Benefits of Sub Slab Depressurization
- Most effective radon reduction method
- Works with all foundation types
- Quiet and energy-efficient
- Long-lasting solution
Quiet, Energy-Efficient, and Long-Lasting
Modern radon fans used in SSD systems are engineered for continuous, long-term operation. They run quietly, producing less noise than a typical bathroom exhaust fan, and consume about as much electricity as a 75-watt light bulb running 24 hours a day. The annual operating cost is typically less than $60, making it one of the most affordable home health protection systems available.
With proper installation and periodic maintenance checks, an SSD system will protect your home for decades. The PVC piping is virtually maintenance-free, and high-quality radon fans from leading manufacturers typically last 7 to 12 years before replacement is needed. When it is time for a new fan, the swap is straightforward and affordable. For homeowners in Billings and Yellowstone County, sub slab depressurization represents the best long-term investment in radon protection for your family.