SpecTips: Maximize Solar ROI with Proper Roof Design
Below are some important factors to consider with design recommendations for specifying and installing a roof with solar:
- Consider the expected life of the solar array when designing the roof: Most PV systems are designed to generate power for 25 years or more, and often the ROI for the building owner is based on this lifespan. If a roof must be torn off during that time, it completely negates the expected ROI. Specifying a roof system designed to meet 25- or 30-year warranty requirements is recommended.
- Design for increased foot traffic: Between installation of the solar array and regular cleaning and maintenance of the panels, roofs with solar typically experience more foot traffic than normal. Specifying a roof with a rigid coverboard, such as Carlisle's SecurShield® HD, can help the roof stand up better to foot traffic. Adding walkway pads and pavers in areas that are expected to receive regular traffic is also recommended.
- Specify the right attachment system: Carlisle always recommends anchoring the solar array into a structural component of the building. Circular or square steel supports are easy to flash with prefabricated accessories. If anchors are installed after the roof is completed, the products listed below can be installed using integrated Carlisle membrane flashings. The seam and flashing material can be included in the roof system warranty if installed by a licensed Carlisle applicator. Options include: Anchor Products U-Anchor 1400, 2400, 3400, 3400s, or 4400 – EPDM, TPO, PVC, & KEE, and HB Solar SKYRACK Mount – EPDM, TPO, PVC, & KEE.
- Leave room for maintenance and inspections: When specifying a solar racking system, ensure there is enough room for a post-solar installation inspection. This will allow a Carlisle Field Service Representative to perform a proper inspection to ensure warranty compliance. It's also important to allow space between the panels and the roof in case any repairs or maintenance are needed in the future.
- Coordinate with Section 481400 – ‘Solar Energy Electrical Power Generation Equipment’ for the specified types of anchoring necessary for the Solar Panel System.
- With a focus on extending the warranty duration, adding a cover board or increasing the thickness of the specified membrane: Add product (membrane thickness/cover board) and quality assurance (warranty) to the Division 7 Section for the membrane being used on the project. 07523 – EPDM, 075419 – PVC, and 075423 – TPO.
For additional information and recommendations, refer to Carlisle’s Solar Ready Roof brochure.
For recommendations and information on installing solar on a Carlisle warranted roof, refer to the Letter of Compliance for PV Installations on Carlisle Warranted Roofs.
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