Back in 2012, solar mounting manufacturer QuickBOLT developed an attachment for PV projects on shingled roofs that didn’t require the conventional metal sheet for flashing. Although it wasn’t the first roof attachment to do so, QuickBOLT popularized minimal flashing and attaching straight through asphalt shingles instead of prying them up and sliding metal flashing sheets underneath.

Credit: SunModo

In the years following release, other manufacturers in the solar mounting market have released their own versions of top-mounted attachments with different methods for flashing, such as chemical sealants and rubber pucks. Through 2021, top-mounts continued to rise in popularity.

Solar mounting and racking manufacturer SunModo had to double the production capacity of its NanoMount attachment three times in the last year. The company has already sold 750,000 units of NanoMount since its debut in 2020, and general manager Steve Mumma said it’s substantially outpacing SunModo’s traditional flashed attachments for composition shingle roofs.

“The biggest problem we’ve had with them all year is getting enough of them,” he said. “We just keep increasing production capacity and the market catches up to it. It’s been a hard year in that regard, because we think next month we’ll be caught up, but by the time we get caught up we’re behind again.”

The appeal of top-mounts is they remove a time-consuming aspect to installing on comp shingle roofs. Each shingle is attached to the roof with multiple nails, leaving installers responsible for prying them up to slide metal flashing underneath. Depending on the condition of the roof, shingles can break in the prying process.

With top-mounts, installers generally locate a rafter, drill a pilot hole, fill it with sealant and secure the lag and flashing — no shingle removal necessary. Certain manufacturers have developed top-mounts that work on the roof decking as well, reducing the risk of missed pilot holes. Although installers are drilling through shingles, manufacturers believe there is less risk for damage to the roof using top-mounts.

The smaller overall footprint and fewer components in top-mounts means reducing shipping costs and fewer trips up the ladder to the rooftop for installers. Manufacturers expect more installers will continue to shift to top-mounted solar attachments.

“I think the trend would definitely indicate that the market is moving that way,” Mumma said. “I wouldn’t say we’d ever see the traditional full-sized flashing disappear because there’s probably going to be some jurisdictions that require it and there’s always going to be some installers that just prefer it. But in terms of market share, I think we will see the market continue to move toward a product like NanoMount.”