Solar Spotlight: Solar mounting hits the deck – Solar Power World

Over the last several years, the shape and size of mounts used in residential solar projects have changed to a lower profile attachment that can be installed over the shingle instead of slid underneath like metal flashing sheets. The next obstacle in residential solar design was expanding these top-mounted attachments that could primarily be installed on rafters onto the decking surface of the roof. Ryan Estrada, technical program outreach manager, and Nico Martinez, senior product manager at Unirac, are here to discuss whats new with solar mounting and, more specifically, the advancement of direct-to-deck attachments.

A written portion of this podcast is below but be sure to listen to the full episode on your preferred podcast service.

Nico Martinez, senior product manager, Unirac.

Nico Martinez: Were starting to see rail-less make a little bit of a comeback here in the solar racking industry. Weve also seen a big push for open channel rail systems, both of which we provide here at Unirac. But rail-less, were starting to see a lot of of our competitors starting to focus on those types of systems. There are some big pros there. It can help reduce the number of attachments, which as we all know, one of the ways that your crews get called back to a house is with roof leaks. So, if you can reduce the number of attachments that are penetrating that roof, that really helps. Then it also helps reduces labor time for crews.

Ryan Estrada: Another trend were seeing is polymeric or chemical flashings for roof attachments. Whats gained a lot of popularity now is the butyl mastic roof attachments, and these will go directly on top of the shingle. So, the benefit there is you dont have to pry nails, you dont have to risk damaging shingles in cold weather when it gets really rigid. You dont have to pop up nails and create holes and then backfill them, and its been tested and tried and true in different industries, and now its making a comeback in solar power on top of your comp shingles.

Ryan Estrada, technical program outreach manager, Unirac.

RE: An interesting topic here because the typical test standards used in the industry are made for connection into the rafter. And so the test standards havent fully caught up to what the industry is doing with deck attachment. So your typical rafter-attached test standards are ASTM 7147, which is a specification for testing and establishing allowable loads of joist hangers. And then theres 1761 which is the standard test for mechanical fasteners and wood-based materials. The gaps that we see in using these standards for direct deck is that its really limited.

NM: What weve discovered when were doing some side-by-side comparison testing with our competitors, especially on the direct-to-deck attachments, is that these loads that some of our competitors are claiming, No. 1, were having a hard time meeting, and No. 2, its in a very controlled laboratory setting. What we really tried to focus on in our testing and this is why weve taken a very strict engineering approach, I know some people may think we might be a little overly conservative sometimes but the reason that we do that is we dont want our cause the issues on your roof, on your solar, because once that starts happening, its not just bad for Unirac, but its bad for the entire industry.

RE: We can all agree that were going to have more severe weather events in the future. And were seeing a high frequency of severe weather, and we expect that to continue. Roofs are designed to withstand uniform loading, so uniform snow loads or uniform wind loads. When you attach direct to deck, youre turning that uniform load into point loads. Once you reach a certain threshold, you can actually start to weaken that roof. We really do our research and due diligence in identifying that and were not just making solar mounting systems, its an ecosystem thats tied in with building and construction, we have to follow the building codes.

Not all direct-to-deck connections are bad, right? Its just a matter of knowing what the limit is and what that threshold is.

This podcast is sponsored by Unirac

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Solar Spotlight: Solar mounting hits the deck - Solar Power World