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As landfill availability decreases and tipping fees increase, solid waste generators
are becoming more interested in finding alternative ways of managing shingle waste. This
site discusses the recycling of asphalt roofing shingles, or "composition
shingles" including shingle quantities, composition, processing, products, and products made with recycled asphalt roofing
shingles.
Asphalt shingle scrap can be used in a variety of products, including:
- Asphalt pavement,
- Aggregate base and subbase,
- Cold patch for potholes, sidewalks, utility
cuts, driveways, ramps, bridges, and parking lots,
- Pothole patch,
- Road and ground cover,
- New roofing, and
- Fuel oil
Approximately 11 million tons of waste asphalt roofing shingles are generated in the
U.S. per year. Re-roofing jobs account for 10 million tons, with another 1 million from
manufacturing scrap. California is estimated to generate 1.2 million tons per year, of
which 1.1 million are tear-offs from re-roof jobs. These quantities may fluctuate with the
construction industry, and with natural disasters such as floods and earthquakes.
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Asphalt roofing shingles are made of a felt mat saturated with asphalt, with small rock
granules added, and are described as follows:
Asphalt cement: 19 to 36 percent by weight. Asphalt used in shingles is
considerably harder than asphalts used in pavement.
- Organic shingles contain 30 to 36 percent asphalt.
- Fiberglass shingles contain 19 to 22 percent asphalt.
Mineral filler/stabilizer (limestone, silica, dolomite, etc.): 8 to
40 percent (90 percent is smaller than .15 mm, 70 percent is smaller than .08 mm.)
Mineral granules (ceramic-coated natural rock, sand-sized): 20 to 38
percent.
Felt backing (mat): 2 to 15 percent. There are two types of mats:
- Organic felt, made with paper (cellulose).
- Fiberglass felt.
Shingles in the waste stream can be either old or new.
Old Shingles. The majority of waste shingles are tear-offs from re-roof jobs or
demolition debris. The load may contain contaminants, such as nails, and wood if the
underlying plywood is also replaced. Roofs are replaced roughly every 20 years. Old roofs
are often overlaid with new shingles, so some tear-offs contain a 20-year-old layer plus a
40-year-old layer. Twenty to forty years ago, most shingles contained organic mats.
New Shingles. After most shingles are manufactured, tabs are cut out to shape
the shingles for assembly. These tabs contain fresh asphalt. Also discarded are new
shingles that did not meet quality standards. Today, most new shingles contain fiberglass
mat.
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To prepare shingles for use in new products, the shingles must be ground to a specified
size, and contaminants removed.
Grinding
Grinding may be easier in the winter when the asphalt is more brittle. If the shingles
begin to stick together in hot weather, or from the heat of the equipment, spraying with
water or blending with sand or gravel may help.
Sizing
Depending on the equipment used, primary grinding may yield 2" or 3"-minus size
pieces. Secondary grinding may be required to make smaller pieces if needed; for example,
aggregate base may require 3/4"-minus, and asphalt pavement may require
1/2"-minus or 1/4"-minus.
Grading
Depending on the use, the shingles may have to be sieved after grinding, to conform to
grading requirements.
Contaminants
For virtually all uses, contaminants must be removed. Possible contaminants may include:
- Metals, which can be removed by a rotating magnet.
- Wood, which sometimes accompanies shingles when the plywood is also replaced in a re-roof
job. Wood can be removed by hand, or floated off in a water flotation unit.
New Shingles
Asbestos is no longer used in the manufacture of asphalt roofing shingles.
Old Shingles
The incidence of asbestos-containing shingles in roof tear-offs today is extremely low.
The total asbestos content of asphalt shingles manufactured in 1963 is only 0.02 percent;
in 1977, it dropped to 0.00016 percent. Due to the practice of covering a worn out roof
with new shingles, there may continue to be a very small amount of asbestos in the shingle
waste stream until about 2016.
Regulations
The agencies regulating asbestos are the U.S.
EPA, CalEPA (Air Resources Board and
Department of Toxic Substances Control), federal Occupational Safety and Health
Administration (OSHA), CalOSHA, and city and county health departments.
U.S. EPA and CalEPA
regulate friable asbestos over 1 percent. OSHA regulates friable and nonfriable asbestos
over 0.1 percent. Processors would need to contact these agencies to determine permitting
and test monitoring requirements, if any.
Most processors improvise by modifying simple equipment. A hammermill will grind
shingles, though it works best with the softer aggregates, such as limestone, rather than
granite. Following is a partial list of manufacturers that sell equipment that can grind
asphalt shingles.
Andela Tool and Machine, Inc.
493 State Route 28
Richfield Springs, NY 13439
(315) 858-0055
Web site: www.recycle.net/andela
Contract
Grinding
4111 Land O'Lakes Blvd., Suite 204
Land O'Lakes, FL 34639
(813) 996-1629
CMI Environmental Machinery (Maxigrind)
P.O. Box 1985
Interstate 40 & Morgan Road
Oklahoma City, Oklahoma USA 73128
(405) 203-0042
Web site:
http://www.terexrb.com
Astec Industries, Inc.
4101-T Jerome Ave.
P. O. Box 72787
Chattanooga, TN 37407
(423) 867-4210
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Siting a shingles recycling plant may require certain State and local permits, such as
air, water, zoning, and possibly solid waste.
Where Can I Get Help?
Businesses starting or expanding into recycling activities may get financial, technical,
marketing, business and permitting assistance from the "R-Team" at CIWMB, at (916)
341-6526.
- Air Permits
The local air districts may be concerned about nuisance odors and various emissions, and
may require processors to spray with water to control dust. The local district may also
want certification that the incoming loads have been tested for asbestos. Locate your
local air district by calling the Air Resources Board at (916) 322-2990 or check
their Web site.
- Water Permits
Your Regional Water Quality Control District may need to permit the facility depending on
feedstock and location. The Regional Board may distinguish between old shingles with hard
asphalt and new shingles with fresh asphalt. Look up your district in a local phone book
under State Government, Water Quality Control Board or
check their
Web site.
- Solid Waste Permits
The CIWMB is currently developing a tiered permitting system; several categories will
require less than a full permit. However, processors that accept segregated C&D
debris may not require a solid waste facilities permit. Contact your Local Enforcement
Agency (LEA) for updates. To find out who the LEA is for the project area, check
the CIWMB's LEA Directory.
All new asphalt roofing shingles manufactured in California are fiberglass-based, and
are produced at the following plants:
Celotex Corp.
Fremont, Alameda County
Los Angeles, Los Angeles County
GS Roofing Company, Inc.
Southgate, Los Angeles County
Wilmington, Orange County
Owens Corning
Compton, Los Angeles County
Pabco Roofing
Richmond, Contra Costa County
GAP Materials Corp.
Fontana, San Bernardino County
Elk Corp.
Shafter, Kern County
Construction Materials Recycling Association
P.O. Box 122
Eola, Il 60519
info@cdrecycling.org
(630) 585-7530
Asphalt Roofing Manufacturers Association
6000 Executive Blvd.
Rockville, MD 20852-3803
(301) 231-9050
National Association of Home
Builders Research Center
400 Prince George's Blvd.
Upper Marlboro, MD 20774
(301) 249-4000
CIWMB Publications
To download or order publications, and to see a
complete publications list, go to the CIWMB
Online Publications Catalog.
Free Directory of Construction Industry
The Blue Book--Building & Construction
P. O. Box 500
Jefferson Valley, NY 10535-0500
(800) 431-2584
(916) 485-3832 (Sacramento rep)
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