Granules are a key component of asphalt shingles. They give asphalt shingles their color, texture, and serve as a layer of protection against UV damage. In today’s post, the local roofing contractors at Lexington Blue® share an in-depth look at asphalt shingle granules.
What Are Granules Made Of?
The granules on asphalt shingles are made of crushed rock, sifted to a certain size and mixed with ceramic granules. Other materials that give the roof certain properties can be mixed in with the granules during manufacture. For example, copper granules can add resistance to blue-green algae, while granules with reflective properties can help reduce heat absorption.
How Are Asphalt Shingles Made?
The asphalt shingle manufacturing process begins by feeding rolls of flexible fiberglass sheets into rollers and soaking them in hot asphalt, cooled down, then soaked again as they pass down the production line. Powdered limestone is also added during one of the passes to add flexibility.
The granule mixture is then pressed onto one side of the still-wet backing material. The nozzles that apply the granules may be loaded with different mixtures depending on the product being manufactured. The still-uncut sheets are then dusted with powdered stone. Strips of adhesive are then applied to the bottom before they are trimmed, packaged, and shipped off to the roof replacement contractor that ordered them.
What Happens When Granules Erode?
Asphalt is vulnerable to UV damage, with prolonged exposure to direct sunlight the primary cause of cracking. This is one of the reasons why paved roads require repaving every few years. Granules protect the asphalt layer from UV damage, and when it erodes over years of wear, this exposes the asphalt layer underneath, resulting in accelerated aging. Signs of UV damage include “bald” spots, shingles curling and cupping at the edges, and parts of the shingles falling off the roof.
Lexington Blue® is your leading provider of roofing and siding services. Give us a call at (859) 368-6346. You can also fill out our contact form to schedule an appointment. We serve customers in Lexington, KY, and the surrounding communities.