TECHNICAL GUIDANCE AND COSTING TO CONDUCT
RADON MITIGATION BY VAPOR EXTRACTION OF
THE BUILDING FOUNDATION
Prepared for:
Building Contractors
Prepared by:
Radon Controls
GeoEnvironmental Services, Inc.
Post Office Box 1555
Mechanicsville, Virginia 23116
(804) 730-8220
Larry J. Giannasi
Virginia Certified Professional Geologist
Virginia Certified Professional Soil Scientist
Federal & State Radon Mitigation Provider
Chris Johnson
Federal & State Radon Mitigation Provider
NRSB #7G0009
Radon Control for Residential Construction
Installation of a soil vapor extraction system during construction has become a more common
practice for many builders in the area for commercial and residential development. Per the
Virginia Statewide Building Code, radon resistant construction techniques shall be required by a
locality (as adopted by local ordinance) in areas of high radon potential, as indicated by Zone 1
on the U.S. EPA Map of Radon Zones (Attached). Although a large part of the metropolitan
area falls within the Zone 1 area, this requirement has yet to be adopted by any of the
surrounding counties, however, many builders are installing systems. Unfortunately, many
systems are being installed improperly and by those not certified to install a radon mitigation
system. Many builders have suffered additional, unexpected expense and costly delays to
correct improperly designed and installed systems prior to closing as a result of testing that
yields elevated radon levels inside the home once construction is compete.
In the
Commonwealth of Virginia qualification requirements must be met to provide radon mitigation
services to ensure systems are installed properly and in accordance with the Federal and State
Radon Mitigation Standards.
Per
the
Code
of
Virginia:
§
HYPERLINK
"http://leg1.state.va.us/cgibin/legp504.exe?000+cod+32.1-229.01" 32.1-229.01 No person shall conduct or offer to
conduct any radon screening, testing or mitigation in the Commonwealth unless he has been
listed as proficient by the United States Environmental Protection Agency, the National Radon
Measurement Proficiency Program of the National Environmental Health Association or the
National Radon Safety Board Certified Radon Professional Program or any other proficiency
program acceptable to the Board of Health to offer such screening, testing or mitigation.
Radon gas is prevalent in central Virginia and elevated radon levels have been documented in
air and water samples among residential structures throughout the area. Given the
overwhelming evidence of the occurrence of elevated radon found in residential homes
throughout the area we believe contractors have a responsibility to act as stewards to
implement a building practice that will greatly reduce an environmental health risk. While we do
not believe it is necessary to require radon resistant construction, we do encourage education
and contracting with certified installers.
Radon Controls is a listed participant in the EPA sponsored NEHA and NRSB certification
programs for radon mitigation contractors as required by the Commonwealth of Virginia. Radon
Controls, a division of GeoEnvironmental Services, Inc., provides professional construction
services to facilitate improved indoor air quality in newly developed residential and commercial
properties. Installation of a radon reduction system (vapor extraction) will reduce potential
exposure to radioactive nuclides, save on costly post construction installation, and remove this
encumbrance from any future real estate transaction. An additional benefit of foundation
venting is the effect of moisture control, dehumidification, and to inhibit mold and fungal growth.
The soil vapor extraction system shall be installed in accordance with Federal EPA Radon
Mitigation Standards per EPA 402-R-93-078.
Radon Controls seeks to encourage the merger of education and technical application to meet
the changing needs of the market and provide for the well being of our community through
responsible development.
INDOOR RADON
The geologic rock formations occurring in the Piedmont region of the Richmond Metropolitan
area are known to contain uranium-bearing minerals, which will decay to form radon gas.
Elevated radon levels have been documented in air and water samples among residential
structures throughout the area.
Radon is a naturally occurring radioactive gas that is tasteless odorless and colorless. It is a
natural decay product of uranium 238, concentrated sufficiently in many different types of rocks
and soil throughout the nation. Successful mitigation of radon gas is achieved by reducing the
source of radon entry. The source of radon gas is largely attributed to the soils, which surround
a structure. Soil gas radon may enter the building through the foundation as natural air changes
occur. Radon gas is a component of soil gas that emanates from the ground surface underlying
building foundations and tends to permeate the overlying structure. Typical mitigation
techniques employ ventilation of these soils to control radon entry.
INDOOR AIR QUALITY
In addition to radon, the soil around your home can contain different types of naturally formed
and manmade gases. Contaminants such as methane, hydrogen sulfide and other volatile
organic compounds (VOCs) from manmade sources may also be present. Mold occurs naturally
in the soil and will produce VOCs. Most of the time these various elements are present in
concentrations too low to detect or to threaten the air quality in your home and cause illness, but
problems can arise with unpleasant and unhealthy effects. The runoff from common pesticides
used in your neighborhood throughout the years, as well as some other naturally occurring
VOCs can adversely affect your family's health. A soil vapor extraction system can assist in
removing these pesticides and VOCs before they have a chance to enter your home's indoor
environment.
Soil gasses that permeate the foundation of your home also allow the induction of significant
amounts of moisture that increases humidity levels and can promote the growth of microbial
contaminants. Mold is one of the leading contributors to respiratory illness for your family. A
majority of cases of chronic sinus infections are a result of contact with mold. Anyone can be
affected by mold, although infants and young children, the elderly and those with compromised
immune systems face the greatest risks. Mold is a biohazard that causes damage to your
home's finish and furnishings that must be professionally removed, often at a great expense to
the homeowner.
All molds, including the stachybotrys strain of mold, need moisture to survive. In fact, moisture is
the only environmental factor that can be controlled that will effectively control active mold in
your home. A soil vapor extraction system will reduce a significant moisture source by proper
ventilation of your home's foundation.
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The soil vapor extraction system serves to remove damaging moisture from the home, reducing
the risk of mold growth and exhausts harmful gases such as radon and VOCs, providing
significant health and comfort benefits.
Radon Controls offers the following professional services to guarantee the elimination of
indoor radon problems and improve indoor air quality.
Foundation Ventilation by Sub-Slab Depressurization (basement homes)
The active ventilation system incorporates a PVC duct system with an in-line blower configured
to draw radon from underneath the building and venting to the atmosphere. Our construction
service requires two site visits. First, following preparation of the foundation and plumbing
rough-in we install a perforated collection pipe within the gravel layer beneath the concrete slab
and stub-out a solid PVC riser in the selected location of vapor extraction. Second, following
framing we attach a solid PVC vent pipe to the riser and route the duct system through an
available chase or through wood frame walls for the installation of the vapor extraction system.
Routing of the pipe shall commence from the foundation and pass through an available chase or
series of the interior walls and into the attic. A radial blower may be mounted in-line and on/off
switch wired to the fan for active ventilation. The duct will be routed through the roof for system
exhaust. Fire stop protection will be provided for penetrations in fire rated walls, ceilings and
floors. Roof flashing and power supply for blower motor to be provided by the site contractor.
Foundation Ventilation by Sub-Membrane Depressurization (crawl space homes)
The active ventilation system incorporates a PVC duct system with an in-line blower configured
to draw radon from underneath the building and venting to the atmosphere. Our construction
service normally requires one site visit. In order to effectively reduce indoor radon
concentrations the crawl space area is effectively depressurized sub-membrane ventilation.
The active ventilation system incorporates a specialized radon barrier and PVC duct system
installed to draw the radon gas out from underneath the membrane (vapor extraction) and
routing through an available chase or through wood frame walls for the installation of the vapor
extraction system. Routing of the pipe shall commence from the foundation and pass through
an available chase or series of the interior walls and into the attic. A radial blower may be
mounted in-line and on/off switch wired to the fan for active ventilation. The duct will be routed
through the roof for system exhaust. Fire stop protection will be provided for penetrations in fire
rated walls, ceilings and floors. Roof flashing and power supply for blower motor to be provided
by the site contractor.
FEE SCHEDULE
Basement/Concrete Slab Foundations
Caulk slab-wall joint and plumbing penetrations, preparation of sub-slab, install vent pipe, fire
stop, mount blower motor and electrical switch and penetrate roof for system exhaust.
Price per unit:*
Passive System
Active System
$ 645.00
$ 995.00
Crawl Space Foundations
Install HDPE pipe beneath specialized membrane used to encapsulate earth floor of crawl
space area, install vent pipe, fire stop, mount blower motor and electrical switch and penetrate
roof for system exhaust.
Price per unit:*
Active System
$1600.00
Building Preparation for Post Construction
We also install ducting in preparation for active ventilation of foundation via vapor extraction.
The following scope of work and cost estimate is on a per unit basis.
Install rigid schedule 40 PVC pipe through building interior and terminate beneath sub-floor and
inside attic space or extend pipe through the roof. Our installation practice accounts for slope
and stability to prevent the accumulation of moisture and vibration once activated.
Price per unit:*
Pipe Installed Sub-Floor to Attic
Pipe Installed Sub-Floor through Roof
$ 350.00
$ 475.00
*All per unit fees are based on a maximum square footage of the building footprint of 1500
square feet. For all homes with a building footprint in excess of 1500 square feet or for any
home that has multiple foundation styles (ex: combination of sub-grade, on-grade, above grade)
Radon Controls will determine the fee for our service based on the construction characteristics of
the individual property.
Radon Controls - A division of GeoEnvironmental Services Inc.
P.O. Box 1555  Mechanicsville, Virginia 23116
Phone: (804) 730-0773  Fax: (804) 730-0167
HYPERLINK "mailto:geo@geoenvironmental.net"
geo@geoenvironmental.net
A Division of GeoEnvironmental Services, Inc.