Homeowners can choose from thousands of asphalt shingle products for their roof replacement project, yet the manufacturing process is basically the same. In this blog, Silver Leaf Contracting shares an inside look at thow asphalt shingles are manufactured.
Roofing manufacturers offer two kinds of asphalt shingles: traditional or “organic” shingles made of cellulose from recycled paper, and fiberglass or composite shingles. Sheets of either backing material are delivered in rolls, and are fed into a machine that spans several rollers. Some of these rollers are positioned several feet high, which can be raised or lowered depending on how much slack is required. Slack can be adjusted to let the workers splice the next roll, keeping a continuous flow of material.
Hot Asphalt and Granules
These rolls of backing material are passed through cascading liquid asphalt, soaking the material through. This makes the backing material water-resistant. The soaked sheets then go through a cooling stage before they’re soaked in asphalt for a second time, this time mixed with powdered limestone for flexibility.
While the asphalt is still wet, ceramic granules are pressed onto one side of the now asphalt-soaked material. Different nozzles release different colors. Depending on the batch made for the day, it could feature dark colors that imitate a slate roof, or bright brown colors that mimic cedar shakes. These ceramic granules may also contain copper granules that prevent algae growth. The sheets of material are then dusted with powdered stone and strips of polyurethane to stop them from sticking together.
Adhesives and Trimming
Many of today’s asphalt shingles feature adhesive strips that enhance wind resistance. Strips of heat-activated adhesive are applied before the sheets are sent to the cutting station. This is where the shingles are cut according to required profiles. Traditional three-tab shingles feature a single layer of material cut into regular patterns, while laminate or architectural shingles are cut into two different profiles before being laminated together. Finally, the shingles are mechanically counted and packaged, ready for delivery.