The United States produces an average of 11 million tons of shingle waste annually from roofing manufacturers and roof tear-offs. But this 11 million tons accounts for almost eight percent of the total annual construction and demolition related waste. Of that 11 million tons, asphalt shingles—the most popular roofing material in the United States—accounts for about 8.8 million tons of waste.
Because it can take up to 300 years for asphalt shingles to fully decompose and the volume of asphalt shingle waste produced is so high, it’s important that businesses and consumers be aware of viable asphalt shingle recycling methods.
Asphalt Properties and Shingle Disposal
Asphalt shingles are made by coating organics (paper, cellulose, and wood) or fiberglass sheets with asphalt and granules of sand, glass, or ceramic – which are added to increase durability. An organic asphalt shingle roof can last from 20–40 years, yet typical roof warranties span approximately 15–25 years. This means total roof replacements happen more frequently than the shingles’ estimated lifespan. Additionally, more expensive fiberglass asphalt shingles can last up to 50 years.
However, when asphalt shingle roofs need replacement due to extensive wind damage, age, leakages or water damage, they are often still well-below their overall lifetime expectancy. This decrease in time used and increase in additional shingle products needed, can cause waste management problems if asphalt shingles are not sustainably disposed of or recycled.
Asphalt Shingle Recycling Benefits
Asphalt, which is a viscous, petroleum-based product (and therefore, a nonrenewable resource), is a great roofing material because it is durable and water-resistant – making it effective at protecting homes from weather-related damage. However, the same material characteristics that make asphalt a great roofing material also make asphalt shingle waste a problem if it is not handled and disposed of properly.
However, recycling asphalt shingles is about more than just keeping these shingles out of landfills. Recycled asphalt can be used to decrease the cost of filling potholes and repaving roads, which can help reduce the burden of road-maintenance costs for taxpayers. Additionally, shingle recycling creates jobs in cities across North America.
Asphalt Shingle Recycling Process
The asphalt shingle recycling process usually involves the repurposing of shingles into an additive for hot-mix asphalt (HMA) or cold patch to fill cracks and potholes in roads. To do this, after the roofing waste is sorted to remove extraneous (non-asphalt) materials, the shingles are ground into smaller particles as per state and local regulations using asphalt shingle grinders, which are specially designed to handle the abrasive material.
In most cases, the shingles are ground into 0.25–2.00-inch pieces, depending on their intended post-recycling purpose. Larger particles are used for base stabilization course – the lower layer of paving, while smaller, finer particles are used in the surface course – the top layer of paving. Typically, HMA can be composed of up to five percent recycled shingles (by weight), and the remaining weight is made up of softer asphalts to offset the hardness of the asphalt shingles.
Looking to improve your shingle recycling process? The General Kinematics, FINGER-SCREEN™ can improve shingle separation for further processing. Contact our resource recovery experts to learn more. Want to learn more about shingle recyclers near you? Learn more at shinglerecycling.org.