RADONReal Estate Professionals Information Series

Causes and Cures

Radon Gas – What is It?

• Natural• Colorless• Odorless• By-product of Uranium

Causes and Cures

Radon is a naturally occurring gas that enters buildings from the

surrounding soil, ground water or building products.

URANIUM

RADIUMIt comes from the decay of

Uranium which breaks down into Radium

and then to Radon gas.

Causes and Cures

RADON GAS

How was it Discovered?

• Mines• Reading prong

What contributes to Radon in Homes?• Location• House type/Airtightness• Pressure differential

Causes and Cures

What is the Concern?

• Radon exposure is reported to be the second leading cause of lung cancer, behind smoking.

• Smoking compounds the effects of radon.

Causes and Cures

Causes and Cures

Where isRadonfound?

Radon in Homes

• Internal negative pressure• Sump pump pits• Cracks in foundation walls

and floors• Gaps between slabs and

walls• Potable water• Gaps around piping through

walls and floors• Granite products (e.g.

countertops)

Causes and Cures

Peculiarities of Radon – levels will vary:

• Geographic location • Type construction• Type mechanical systems• Time of day• Weather conditions• Time of year – seasonal changes • Occupant lifestyle• Other factors

Causes and Cures

1.2 pCi/L

0.3 pCi/L

6.8 pCi/L 2.1

pCi/L0.5

pCi/L

4.8 pCi/L 10.0

pCi/L 1.4 pCi/L

Causes and Cures

Level will vary House-to-House Concerns

Causes and Cures

Radon Mitigation Action Levels

• Radon is measured in picoCuries/Liter.• Radon measurements below 4 pCi/L – Radon mitigation is generally

not required. • Radon measurements of 4 pCi/L or higher – Radon mitigation to

lower annual radon exposure is recommended. • Radon levels fluctuate with weather and atmospheric changes over

the course of a year. Long-term testing will give better indications of the annual radon potential.

Radon Action Level = 4 pCi/L or higher

Radon Detection Devices

• Charcoal Canisters• Electret Ion Chamber• Charcoal Liquid Scintillation• Continuous Monitors• Alpha Track (long term) • Radon in Water

Causes and Cures

Radon levels fluctuate with weather and atmospheric changes over the course of a year. Long-term testing will give better indications of the annual radon potential.

Short-term Screening

• Canisters, Electrets, Liquid Scintillation- Readily Available- Reasonable Turn-around- Unsupervised- Gives Snap-shot- Affordable

Electret

Charcoal Canister

Monitor

Liq. Scintillation

Charcoal Bag

Causes and Cures

Monitor

Causes and Cures

Short-term Screening

• Continuous Monitors- Interval Readouts- Identifies Irregularities/Tampering- Reasonable Cost- Prompt Results

Monitor

Causes and Cures

Long-term Testing Options

• Continuous Monitors

• Alpha Track (90 days)

• Electrets

• Not usually with Real Estate Transaction

Alpha TrackContinuous radon Monitor

Testing Conditions

• Closed house conditions

• Lowest livable area

• Not in kitchen, bath or laundry room

• Not in crawlspace

• No fans operating

• Normal HVAC operation

• Normal entry / exit by occupants

Causes and Cures

Testing Conditions

• For short-term tests, all windows and external doors, on all floors, should remain closed, except for normal entry and exit.

• For tests lasting less than 4 days, closed house conditions must be initiated 12 hours prior to starting the test.

• Testing methods will also depend on whether testing is associated with a real estate transaction and local requirements.

Causes and Cures

Lowest Lived In

Finished

Basement

Unfinished Basement

Not for Sale

Lowest Lived InFinished

BasementUnfinished Basement

Real Estate Transaction

Up to the homeowner and their use of the home.

Local requirements - Based on the use of the

“space” in the home.

Also, Agreement between Home Buyer and Seller.

Causes and Cures

Quotes from the Home Buyer’s and Seller’s Guide to Radon:“…the test is done in the lowest level of the home suitable for occupancy. This means the lowest level that you are going to use as living space which is finished or does not require renovations prior to use.”

“EPA recommends that testing device(s) be placed in the lowest level of the home suitable for occupancy. This means testing in the lowest level (such as a basement), which a buyer could use for living space without renovations….

….A buyer and seller should explicitly discuss and agree on the test location to avoid any misunderstanding. Their decision should be clearly communicated to the person performing the test.”

Causes and Cures

EPA Guide for Radon Testing in Real Estate Transactions

RESIDENTIALRADON LEVELSCAN BE

LOWERED

Causes and Cures

• Ventilation

• Sub-slab Depressurization (Suction)– Seal cracks and gaps in subgrade walls and floors– Seal sump pump pits– Run PVC pipe through floor slab to exterior– Install inline continuously operating fan

• House Air Pressurization– Install continuously operating fan to maintain positive

air pressure within subgrade areas orhouse

Causes and Cures

Radon Mitigation Methods

Causes and Cures

Room or Wall Ventilation(least effective)

Sub-slab Depressurization

Most common method of removing Radon from the home. A negative pressure is created under the floor slab with a continuously operating fan and potentially radon ladened air is vent through PVC piping to the outdoor air above the roof.

Also referred to as Sub-Slab Suction.

Causes and Cures

Causes and Cures

Sub-slab Depressurization

SUB-SLAB SUCTION

Causes and Cures

Sub-slab Depressurization

Causes and Cures

Components for Sub-slab Depressurization

Home Under ConstructionLess than $500

Existing Home$800 - $2200

Causes and Cures

Radon Mitigation – Typical Costs

Radon Tester Credentials

To become a Qualified Radon Tester typically requires:• Radon Measurement Course

• National Radon Measurement Exam

• Local Licensure, and/or

• Certification through either:

- National Radon Safety Board

- National Environmental Health Association

Causes and Cures

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