Over the last several years, there has been increasing evidence of Radon gas build-up in homes causing lung cancer. A recent article by Scott Learn in The Oregonian underscored how the prevalence of Radon here in Portland is more than twice the national average. Legend Homes takes this seriously, and has been using construction methods and systems to prevent these dangers, for years. The State of Oregon adopted new codes to address this in 2010, but only for new homes and large renovations, and in only a few counties. We feel it is important that you understand the issue, and what Legend Homes is doing about it.
What is Radon Gas?
Radon gas is defined as “A naturally-occurring, chemically inert, radioactive gas that is not detectable by human senses. As a gas, it can move readily through particles of soil and rock and can accumulate under the slabs and foundations of homes where it can easily enter into the living space through construction cracks and openings.” It is a heavy gas, and can accumulate in enclosed spaces without ventilation.
Legend Homes addresses this threat in several ways:
- Crawl space foundations: Unless you have a steep lot requiring a basement, we avoid building on concrete slabs lying on the ground. The crawlspace has non-closable vents installed per code. With insulated floors, there is no need to close your vents, and since Radon is heavy, it will exit through the vents before building up to the floor level. We install 6 mil black polyethylene on the ground, to encourage any gas rising under it to exhaust near the perimeter wall, where the vents are located.
- Ductwork in conditioned space: As an element of our energy conservation measures, there are no ducts located in the crawlspace that could collect Radon and pump it into the home.
- Sealing, Testing, and Certification: Another advantage of our energy conservation efforts, the entire conditioned envelope of the living space is sealed, following the Energy Bypass Checklist from Energy Trust of Oregon. A third party verifier inspects the sealing efforts, and then performs a Blower Door Test at the completion of construction. When the test proves low levels of air leakage, he certifies the home and provides the results. Now you can be confident Radon is not leaking in.
- Whole House Ventilation System: As part of our air quality assurance, Legend installs a ventilation system designed to replace the air in the home with fresh air regularly. This prevents any gases from accumulating, including those from construction materials and cleaning supplies to pets and new furniture.
If your Home Inspector asks about this, the home complies with ORSC Section F103.5.2, Sections R408.1 and R408.2, and ventilation rates specified in Table N1101.1(3). If your particular home is on a steeply sloping lot, resulting in a basement floor slab, there are additional methods used that we will go over with you.
Rest assured that Legend Homes understands Radon, and protects you from it.