Written by: Jef McCurdy
National Training Manager - Castagra
What Is The Most Sustainable New Commercial Roofing System?
Sustainable is such a loaded word nowadays. Regardless of how toxic a manufacturer's products are, they can pick and choose stats to make sustainability claims.
To evaluate sustainability, I would look at several criteria:
My first consideration would be the life of the product being installed if left untouched.
- Metal roofs, especially copper, can last 25+ years with minimal maintenance.
- Gravel Surfaced BUR is also a contender for longest-lasting/lowest maintenance.
- Quality mod-bit, PVC, and EPDM would be next for longevity.
My second criterion would be initial impact. Since no commonly used commercial roofing material is made of recycled materials, they're all starting with new materials.
- I would give metal a low initial mark, but high marks for the fact that they are made from easily recyclable materials. Longevity plays here as well as they are not being replaced often.
- While people generally do not think of petroleum-based products as sustainable, it is worth considering that the asphalts used for BUR and Modbit are derived from junk or waste created in the refining of oil for other uses. If not used for these materials, the waste would have to be disposed of via alternate means. From there, I do not know how impactful the processes are.
- PVC and EPDM, while recyclable, are rarely recycled. There is no financial incentive like there is selling metal for scrap. And, while also made from oil derivatives, PVC and EPDM are made from premium petroleum materials that are likely to be used in other manufactured goods.
Of the longest-lasting materials, I would give asphalt-based products high marks for initial impact followed by metal, and finally PVC/EPDM. These rankings are current, but not likely to remain static as the world changes. As we shift from internal combustion to electric vehicles, asphalt byproducts may no longer be in ready supply. As recycling evolves, I expect to see metal and single-ply roofs made of post-consumer recycled materials.
My third criterion would be maintainability. This can be an equalizer for materials with a lower "left-alone" longevity. I believe all new construction should have a maintenance plan that includes and provides specific provisions for the aging of the roof.
- Even a short-lifespan material like TPO can last indefinitely if maintenance coatings are applied before serious degradation and maintained regularly.
- Spray Polyurethane Foam has gotten a bad rap in the industry but can last as long as any other material with regular maintenance coatings.
- Maintainability is where Gravel Surfaced BUR gets low marks
Maintenance Coating Program
The key is to introduce maintenance coatings before the material is too far gone. I would recommend starting a coating program as follows:
- Metal - year 15-20
- Gravel Surfaced BUR - year 13-18
- Modbit/PVC/EPDM - year 9-15
- TPO - year 6-8 (or as soon as the plasticizers have migrated enough to adhere a coating)
Most Sustainable New Construction Roof System?
My “perfect world” theoretical most sustainable new construction roof would be a single-ply system made of post-consumer recycled materials and maintained with a sustainable coating like Ecodur+ from the moment it is ready to receive a coating system.
However, we must acknowledge that most building owners will not follow roof maintenance guidelines. Most roofs will be ignored until tear-off is the only option, creating endless landfill waste and the need for new materials.
All things considered, I say initial longevity is still king and copper is the most sustainable new construction roofing material.
Another consideration that I hope to introduce to the conversation soon is the coming Castagra new commercial roofing spec. We are still working out the details and testing options. But sustainability, longevity, and reparability will all be important considerations as we develop the system.
I am not a sustainability expert, but I find it to be an interesting topic. We would love to hear your thoughts. Did I miss anything? Is there another angle? What about an emerging material that was not discussed? Do you think sustainability should be a major consideration when choosing new roofing materials?
Written by: Jef McCurdy
National Training Manager - Castagra
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