During our recent home roof replacement project, I decided to find out about asphalt shingle recycling and share what I learned.
Our Home Roof Replacement Project
We bought our now 23-year-old home about 5 ½ years ago. Before the sale closed, a professional home inspector pronounced the 25-year asphalt shingle roof was in good condition. We have never had any leaks so we were not looking to replace our roof.
That is until we decided to put solar panels on our roof. Dismantling the photovoltaic system at some point in order to replace the roof seemed like a complex and expensive project. We met with a roofing contractor and mulled over whether to replace just the roof where the solar panels would be installed or the whole roof. The roof was nearing the end of its 25-year lifespan and some areas were badly worn. Without a crystal ball, we did not know if the roof would last for 2 years or 10? We decided to go with replacing the whole roof now.
We selected a 50-year asphalt composition shingle. Perhaps not the most eco-friendly material, but a roof that will last for 50 years is environmentally friendly.
We compost and recycle most of our household waste and have very little garbage. So naturally we wanted to know what would happen to our home’s existing asphalt shingles. I asked our contractor. He told me, in our county, construction waste is sorted after it arrives at the landfill and asphalt shingles are recycled for use in asphalt road pavement.
The new roof looks great and passed the first rain test.
Asphalt Shingle Environmental Impact
The U.S. EPA’s Waste Reduction Model (WARM) was used to compare net greenhouse gas emissions associated with asphalt shingles in four waste management alternatives: source reduction, recycling, combustion, and landfill disposal.
As part of the California Global Warming Solutions Act of 2006 (AB32), the California Integrated Waste Management Board is tasked with implementing waste management strategies to reduce the production of greenhouse gases. Per a 2008 report, asphalt roofing materials represented 2.8% or 1,121,945 tons (+/- 1.5%) of waste just in California landfills.
Although asbestos hasn’t been used in asphalt shingle manufacturing for decades, some old roofs may have shingles with asbestos content. U.S. EPA, state, and local regulations cover testing, handling, and disposal of materials containing asbestos.
Recycled Asphalt Shingle Uses
According to the Construction Materials Recycling Association (CMRA), the recycled asphalt shingle (RAS) industry got its start in the 1970s and 1980s. The market for RAS is growing due to landfill reduction programs and regulations, and conscientious building and home owners demanding recycling programs. Recycled asphalt shingle uses include:
Hot-Mix Asphalt (HMA)- Cold Patch
- Dust Control on Rural Roads
- Temporary Roads or Driveways
- Aggregate for Road Base
- New Shingles with Recycled Content
Asphalt Shingle Recycling Process
The asphalt shingle waste stream is composed of leftover material from manufacturing new shingles and as a result of new or replacement roof construction. As part of the recycling process, shingle waste is ground to a specific size and contaminants are removed.
- Grinding – the initial step
- Sizing – secondary grinding into smaller pieces if needed
- Grading – sieving after grinding, if required
- Contaminant Removal – nails, metals, wood, and other materials
Shingle recycling operations must comply with local, state and federal regulations.
Although asphalt shingle recycling has come a long way, asphalt is still a petroleum-based product and recycling asphalt shingles are not without its own environmental impact.
Resources
- CalRecycle – Construction and Demolition Debris Recycling
- Construction Materials Recycling Association (CMRA)
- Earth911 – Infographic: Recycling Shingles
- ShingleRecycling.org (CMRA website) – Markets for Recycling Asphalt Shingles
- U.S. EPA – Analysis of Recycling of Asphalt Shingles in Pavement Mixes from a Life Cycle Perspective (revised document)
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