Shingle Recycling With Compassion
Did you know that shingles can be recycled? They sure can!
Go Green with Shingle Recycling!
Background on Shingle Recycling
Asphalt roofing shingles are made of a felt mat saturated with asphalt, with small rock granules added, and are described as follow:
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 .15mm, 70 percent is smaller than .08mm) Mineral granules (ceramic-coated natual 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 ever 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 Shingle
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.
Processing Steps
To prepare shingles for use in asphalt pavement, the shingles need to be processed according to end use specifications and for state projects according to specific state Department of Transporation sepecifications. This typically includes removing non-shingle debris and properly sizing the material for each end use application.
Grinding
Typically grinders are used to size the shingles initially.
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.
Where Do Recycled Shingles Go?
Recycled asphalt singles can be used in a variety of end uses, including:
- Asphalt pavement
- Alternative fuel used in Power Plants and Cement Kilns
- Cold Patch – for potholes. Sidewalks, utility cuts, driveways, ramps, bridges, and parking lots
- Pothole patch
- Road and ground cover
For Roofers
- Promotes green construction for LEED credits or certification projects
- Significantly reduces shingle disposal cost – much cheaper than the landfill
- Shingle recycling can be used as a selling point to homeowners
- Minimizes waste stream from going into the landfill
- Various states are expected to ban the disposal of asphalt shingles in landfills.
Hot Mix
- Improved resistance to pavement cracking
- Improved resistance to rutting
Benefits: For Coal Fired Power Plants and Cement Kilns
- Reduces cost of virgin fuel – coal and fuel oil
- Reduces carbon footprint of the facility
- Promotes green sustainable technologies
- Asphalt has an energy value of 17,000 BTU’s/lb
- Conservation of natural resources by reducing the demand for oil and mined aggregate
- Conservation of landfill space by keeping roofing shingles out of landfills
- Produces longer lasting roads.
Benefits: For The Community
