Rubberized roof coatings have been around for decades, but typically, they’re used to seal flat or shallow slope roofs, and contain some mix of asphalt. StrongSeal, a new self adhesive, walkable underlayment for pitched roofs, is made without asphalt, and contains a high percentage of recycled crumb rubber from both industrial waste and discarded tires.
This product should help address one of the worst product mismatches in the building industry—50-year roofing materials (such as clay tile, slate, concrete, or metal) installed on top of 15–20 year underlayment.
The manufacturer asserts that “The life cycle of StrongSeal meets or exceeds that of the roof covering, minimizing life-cycle costs.” The company’s technical services manager, Keith Chappe, says testing on the product found little variation after one year of exposure. Unlike products containing asphalt, he says, StrongSeal doesn’t lose light oils—so it doesn’t dry out. And it has a proprietary UV stabilizer. The company has not yet completed the product’s full life cycle assessment. A roof on a typical 1,800-square-foot home recycles about 11 tires.
Is Tire Rubber Safe?
We’re enthusiastic about the green potential of recycled rubber products. The next step for manufacturers: show us that they’re safe--that they won’t leach toxins into our soil or drinking water. Tires were not designed for close human contact. They often contain cadmium, lead, zinc, arsenic, and other potential hazards. We’d like to be able to confidently say that recycled rubber products should not preclude a homeowner from putting in a rainwater catchment, or planting a garden next to the house.