History and Types of Asphalt Shingles
– Asphalt shingles were invented by Henry Reynolds in 1903 and became popular in parts of America by 1911.
– By 1939, 11 million squares of shingles were being produced.
– The growth in popularity of asphalt shingles during the 1920s was influenced by a campaign to eliminate wood shingles on roofs.
– Two types of base materials are used to make asphalt shingles: organic and fiberglass.
– The top surface of shingles is covered with granules made of various materials, and the underside is treated to prevent sticking.
– Organic shingles were made with a base mat of materials like waste paper, cellulose, or wood fiber, while fiberglass shingles have a base layer of glass fiber reinforcing mat.
– Fiberglass shingles gradually replaced organic shingles and became more widely used by 1982.
Impact Resistance and Wind Resistance
– A partnership was established in 1996 to create an impact resistance classification system for roofing materials.
– The system, known as UL 2218, established a national standard for impact resistance.
– Insurers offered discounted premiums for structures using shingles with the highest impact classification (class 4).
– The American Society of Civil Engineers ASTM D7158 is the wind resistance standard for asphalt shingles.
– Some shingles use a fabric backing known as a scrim to make them more impact-resistant.
Qualities and Durability of Asphalt Shingles
– Asphalt shingles come in various shapes, textures, and designs, including architectural and three-tab options.
– Architectural shingles are thicker, stronger, and offer more aesthetic appeal, while three-tab shingles are simpler and lighter.
– Laminated shingles provide a contoured visual effect and better water resistance.
– Asphalt shingles have varying warranted life, ranging from 20 years to lifetime warranties.
– Shingle durability can be affected by thermal shock, weather consistency, roof orientation, and ventilation.
– Shingles should not be applied in temperatures below 10°C (50°F).
Maintenance and Disposal of Asphalt Shingles
– Regular physical removal of debris and organic growth can prolong the life of shingles.
– Algae and moss growth can be prevented with zinc or copper strips, and black algae growth can be removed with a bleach solution.
– Chemical solutions like copper sulfate or zinc chloride can be used for organic growth removal.
– Approximately 11 million short tons of asphalt shingle waste is generated in the US annually.
– Proper disposal methods and recycling options for asphalt shingles should be explored to reduce waste.
Recycling of Asphalt Shingles and Health Concerns
– Reclaimed asphalt shingles (RAS) can be broken down and incorporated into asphalt concrete mixtures.
– RAS are an attractive component in recycled asphalt mixes due to their high content of asphalt cement.
– The use of RAS in recycled asphalt mixes is restricted in some states due to concerns about asbestos in older shingles.
– Testing has shown a low percentage of asbestos-containing post-consumer shingles.
– Recycled asphalt mixtures offer increased sustainability, reduced need for virgin materials, conservation of resources, and lower energy consumption.
