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Here we discuss the level of radon hazard likely to be found in underground houses, and how to prevent radon gas contamination in concrete and underground houses.

See Radon Hazards for details about radon in buildings, its health effects, how to measure radon, the effect of radon contamination on real estate values and home sales, and a guide on how to remove radon from buildings. Also see ENVIRONMENTAL HAZARDS - INSPECT, TEST, REMEDY for our full list of environmental hazard identification and remedy related to buildings.

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Q&A: What is the Radon Hazard in Underground Houses & How do I Prevent an Indoor Radon Gas Problem

The link to the original Q&A article in PDF form immediately below is followed by an expanded/updated online version of this article.

• "Radon Basics", for Underground Homes - Q&A article, Solar Age, April 1984 - PDF version, Use your browser's back button to return to this page

The question-and-answer article below paraphrases, quotes-from, updates, and comments an original article, (see links just above) from Solar Age Magazine and written by Steven Bliss.

Radon Basics

Question:

I plan to build an underground house of concrete. The location will be in the Northwest where there is a lot of granite rock. I would appreciate any information you can give me on radon in underground housing. -- Harold F. Williams, Lakeport CA

Answer:

Radon is a colorless, odorless gas released during the natural decay of radium, an element found throughout the earth's crust. Concentrations of radon vary greatly from an average of 0.7 picocuries per gram (of soil) in North American soils to seven to ten times that in New Hampshire granites.

Radon enters the home primarily through cracks in the foundation, from unpaved and unvented crawl spaces, and from sump pump pits. Water from deep wells can also be a source of radon gas in air and water in buildings, as can stone and masonry construction materials themselves, particularly when directly exposed to interior spaces. [That's why we don't conduct a radon test indoors by placing the test canister on the brick or stone fireplace mantel--DF].

There is evidence that the average home in the U.S. contains twice the atmospheric level of radon and that basements, on average, contain higher concentrations of radon gas than upper stories.

Radon levels indoors are reduced by good building practices such as thorough sealing and waterproofing, positive drainage, and granular backfill - which keep the radon gas out of the house and allow it a route to the outdoor soil surface.

Indoor air ventilation to 0.5 air changes per hour (ACH) should minimize any radon-related health hazard except under extraordinary conditions, and water borne radon can be filtered out with charcoal.

Medical experts agree that long-term exposure to low-level radon gas increases the likelihood of lung cancer, but the degree of risk is unclear. Radon levels found in problem homes have been compared in risk to smoking one to three cigarettes a day.

If you are concerned about the proposed building site for your underground home, radon detectors from Terradex Corporation can assess the level of radon present in soil at the building site.

This article is reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.

The text below paraphrases, quotes-from, updates, and comments an original article, (see links just above) from Solar Age Magazine and written by Steven Bliss.

The question-and-answer article about ... , quotes-from, updates, and comments an original article, (see links just above) from Solar Age Magazine and written by Steven Bliss.

Here we include solar energy, solar heating, solar hot water, and related building energy efficiency improvement articles reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.

Additional Radon details quoted from How to Remove Indoor Radon are just below.

If radon levels need to be lowered further, the system can be easily converted to an active system by adding an inline fan, which can meet the target levels in nearly all cases (see Figure at above left, showing a typical radon mitigation system installation). The goal of radon remediation is to lower the average indoor radon gas level to less than 4 pCi/L, and preferably 2 pCi/L.

-- Adapted with permission from Best Practices Guide to Residential Construction.

Detailed Articles about Radon: detection, correction, & prevention in buildings

  Radon Hazards
    Health Effects of Radon
    Guide to Measuring Radon
    Effects of Radon on Home Sales
    How to Remove Indoor Radon
    Radon Hazard in Underground Homes

"Radon Basics", Q&A article, Solar Age, April 1984, includes advice for radon-resistant construction for an underground house built of concrete

See Radon Enviro-Scare for a full discussion of the normal cycle of public fear that accompanies the discovery and publicity of various environmental hazards, including radon gas and see Enviro-Scare, the Cycle of Public Fear for our article about consumer environmental safety worry cycles that change over time.

For a Thorough Background in Radon Hazards, Radon Mitigation, & the History of Radon Concerns in the U.S. also see these articles reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.

• "Radon's Threat Can Be Subdued", part 1 - William Turner, Terry Brennan, Solar Age Magazine Radon and its progeny are the slipperiest pollutants in the indoor environment, but there are simple ways to keep radon and its relations at bay.
• "Radon's Threat Can Be Subdued", part 2 - what is radon, where does radon come from, how does radon get indoors, and why is radon a problem in buildings.
• "Radon's Threat Can Be Subdued", part 3 - standards for airborne radon levels in buildings and recommended levels of radon for action, how radon is best detected, and radon action plan.
• "Radon's Threat Can Be Subdued", part 4 - radon prevention advice for new construction, radon in well water - how it is removed, sources of information about radon gas and radon contamination.

• "Defeating Radon" part 1- Terry Brennan, Bill Turner, Solar Age Magazine - How does radon get into buildings, how do I know if a building has a radon gas problem, how can I solve radon problems in existing homes, and what can I do to prevent radon from entering new homes. Part 1: where Radon comes from, how to diagnose radon
• "Defeating Radon" part 2- Guide to keeping radon out of new houses - design details
• "Defeating Radon" part 3- Key spots to seal, to stop radon gas leaks into buildings
• "Defeating Radon" part 4- Data on radon levels in buildings before & after radon mitigation treatment
• "Defeating Radon" part 5- Air filtering, testing after radon mitigation, where to buy radon tests

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• Daniel Friedman - principal author/editor of the InspectAPedia^® Website
• Steven Bliss served as editorial director and co-publisher of The Journal of Light Construction for 16 years and previously as building technology editor for Progressive Builder and Solar Age magazines. He worked in the building trades as a carpenter and design/build contractor for more than ten years and holds a masters degree from the Harvard Graduate School of Education. Excerpts from his recent book, Best Practices Guide to Residential Construction, Wiley (November 18, 2005) ISBN-10: 0471648361, ISBN-13: 978-0471648369, appear throughout this website, with permission and courtesy of Wiley & Sons. Best Practices Guide is available from the publisher, J. Wiley & Sons, and also at Amazon.com.
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Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

ENVIRONMENTAL HAZARDS GUIDE
AIR POLLUTANTS, COMMON INDOOR
ALLERGEN TESTS for BUILDINGS
ALLERGENS in BUILDINGS, RECOGNIZING
ALLERGY TESTS for PEOPLE
ALLERGY TEST ACCURACY
FLOODS IN BUILDINGS-priorities
FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP
MOLD: A COMPLETE GUIDE TO MOLD
ACTION GUIDE - WHAT TO DO ABOUT INDOOR MOLD
INDOOR AIR QUALITY & HOUSE TIGHTNESS
INDOOR AIR QUALITY IMPROVEMENT GUIDE
  Health Effects of Air Pollutants
  Common Indoor Air Pollutants
  Key Strategies for Improving Indoor Air Quality
  Whole House Ventilation Strategies
  Exhaust-Only Ventilation
  Supply-Only Ventilation
  Balanced Ventilation
  Air Filtering Strategies
  Particles in Indoor Air - Chart
  Quick Guide to Gases
  Air-Cleaner Types
  Air Filter Effectiveness
  Real-World Effectiveness of Air Cleaners
  Finding & Reducing Air Pollutants
  Radon Hazards
    Health Effects of Radon
    Guide to Measuring Radon
    Effects of Radon on Home Sales
    How to Remove Indoor Radon
    Radon Hazard in Underground Homes
  Formaldehyde Hazards
  Biological Pollutants
  Volatile Organic Compounds VOCs
  Pesticide Exposure Hazards
  Lead Exposure Hazards
  Asbestos Exposure Hazards
  Carpeting and Indoor Air Quality
  Combustion Appliance Contaminants
  Backdrafting Appliances
  Fireplace & Woodstove Contaminants
  INDOOR AIR HAZARDS TABLE
  INDOOR COMBUSTION PRODUCTS & IAQ
INDOOR AIR QUALITY METHODS COMPARED
LEAD POISONING HAZARDS GUIDE
MOISTURE CONTROL in BUILDINGS
MOLD ACTION GUIDE - WHAT TO DO ABOUT MOLD
MOLD ATLAS & PARTICLES INDEX
MOLD BY MICROSCOPE
MOLD CLASSES, HAZARD LEVELS
MOLD CLEANUP GUIDE- HOW TO GET RID OF MOLD
MOLD DETECTION & INSPECTION GUIDE
ODORS, Smells, Gases in Buildings-Diagnosis & Cure
RENTERS & TENANTS GUIDE TO MOLD
SEWAGE BACKUP TEST & CLEANUP
STAIN DIAGNOSIS
TECHNICAL & LAB PROCEDURES
THERMAL TRACKING

• Terradex Corporation, 460 Wignet Lane, Walnut Creek CA 94598 415-938-2545
• RTCA, the Radon Testing Corporation of America, is in Elmsford, NY - 800-457-2366 sells radon testing kits and equipment and provides radon mitigation services (RMCA)
• "Radon Basics-PDF", Q&A article, Solar Age, April 1984, includes advice for radon-resistant construction for an underground house built of concrete

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

• Our recommended books about building design, inspection, and repair, and about indoor environment testing, diagnosis, and cleanup are at the InspectAPedia Bookstore.
• Best Practices Guide to Residential Construction, by Steven Bliss. John Wiley & Sons, 2006. ISBN-10: 0471648361, ISBN-13: 978-0471648369, Hardcover: 320 pages, available from Wiley.com and also at Amazon.com. See our book review of this publication.

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