First in a series: Attachments for Composition Shingle Roofs
There are an overwhelming number of solar roof mounting attachments on the market and more are released every year. Selecting the right product can seem daunting. Believe me, I know how it feels! For a great portion of my solar career, I worked for a large solar integrator where I was responsible for vetting and approving mounting equipment. What I quickly learned was that mounting and racking affected every part of the business and every single department had needs. The list of requirements was long. Through much trial (and some error) my team developed a comprehensive evaluation process. In this article I share the top takeaways from that process and key features that make a big difference when selecting roof attachments for composition shingle roofs. Next month I’ll share my recommendations for selecting attachments for tile roofs.
Roof Attachments for Composition Roofs
There are two main types of solar roof attachments for composition shingle roofs—flashing and flashing-free. Both have advantages and disadvantages, so it’s important to understand the differences and select the attachment type that is the best fit for your project.
Flashing is the industry standard, widely accepted by Authorities Having Jurisdiction (AHJs) and familiar to installers. Flashing’s primary waterproofing mechanism is simple: a flat metal flashing is inserted between shingle courses and sheds water down the slope of the roof. In order to insert the flashing between the courses, however, the shingles must be pried apart and nails removed from the roof deck. This process disturbs the roof shingles and, if not done properly, can weaken or tear them, thereby compromising the roof envelope. Therefore, it’s important to install a quality attachment which will help you to do the job right.
Here’s what to look for when selecting a flashed attachment:
- The metal flashing should flex when inserted between the shingle courses, but be rigid enough to spring back to a flat profile so that it does not lift the shingle and leave lumps in the roofing. Stay away from super-thin or malleable metals which can easily bend and crease; installers refer to this as “potato chipping.”
- The corners of the metal flashing should be rounded. This detail may not seem important, but square corners will cut hands, gouge roofs, and catch on shingles while being inserted into place.
- The width of the metal flashing should be less than 8½ inches. This width is more than adequate for waterproofing and any extra material has no benefit and only makes installation more difficult by catching on shingles and roofing nails while its inserted into the course of shingles.
- Marks on the edges of the flashing which aide installers to quickly align attachments with roof shingles.
While flashing-free mounts may comply with the same building codes and pass the same certification tests as flashed mounts, many AHJs are not familiar with the technology and may require extra documentation and initial education.
Flashing-free attachments take a different approach to waterproofing, relying on high-grade sealants to seal penetrations in the roof, and are installed without prying, disturbing, or damaging shingles.
Many installers prefer the flashing-free installation process as it requires less bending over and there is no need to kneel on hot roofs. Additionally, there are fewer parts and pieces to install, making it a much more streamlined process.
There is a range of flashing-free attachments on the market. Here are the important features:
- Allowable spans should be comparable to spans for flashed attachments, otherwise you may end up installing more attachments and negating the labor savings of the flashing-free attachments.
- The method of waterproofing should conform to variations in shingle thickness, including across the raised sections of architectural shingles. Products that use peel-and-stick mastic typically cannot be installed across shingle tabs or raised sections.
- Installation should not require installers to apply, or directly handle sticky or messy materials which can slow down the process.
- Many flashing-free attachments can be easily installed on rolled comp roofing, unlike flashing attachments.
Note: Some flashing-free products can be direct-to-deck mounted. The advantage to installing direct to deck is the time saved from locating roof rafters. The disadvantage is that in most loading conditions the installer will need to install more mounts, thus erasing the labor savings. If you look into a direct-to-deck mount be sure to evaluate the trade-off between time savings and the cost of additional attachments.
General Product Requirements
Once you’ve decided on the appropriate method of attachment (flashing or flashing-free) for your project, start looking at specific products. Regardless of attachment type, verify that the product meets these criteria:
- Certified to TAS-100 Wind Driven Rain Test and UL-441 Rain Test
- The waterproofing system should have redundant layers of protection. You don’t want any call backs for leaks and look for peace of mind that comes from a “belt and suspenders” approach to waterproofing the roof penetrations.
- Like any solar product you install, the attachment should be designed, manufactured and warranted by a reputable company with a solid track record of industry experience. Make sure you have confidence in the company’s product and the company’s ability to support you.
- The product should have no more than three components. Having more than three pieces to assemble causes lost parts, unnecessary frustration for installers, and slows installation.
Unirac’s Attachments for Composition Shingle Roofs
Flashkit Pro is Unirac’s flashing solution. It meets my criteria for a flashing solution and features a ribbed flashing for high strength which prevents “potato chipping” and ensures the flashing lays flat on the roof. The ribs are contoured to redirect water and play a part in Shed & Seal, Unirac’s redundant leak protection, which includes a dual flange water seal and raised cylindrical hole that encapsulate the roof fastener to prevent leaks. Flashkit Pro is certified to TAS-100 and UL-441. Everything you need – flashing, lag bolt, mounting hardware – is packaged inside the kit. To learn more, checkout this video.
Flashloc is Unirac’s flashing-free solution. It meets the requirements for flashing-free attachments which I outlined above, and is secured with a standard lag bolt which transfers loads directly into the rafters for high-strength and wide spans. After securing the mount, sealant is injected into the attachment to create a pressurized adhesive seal. The hard, outer shell and roof gasket provide the redundant seal, the Triple Shell. Flashloc is a quick and clean install without any of the collateral damage that can occur while prying and cutting shingles. It installs on both rolled comp roofing and composition shingles and meets TAS-100 and UL-441. The attachment, lag bolt, and sealant are packed together. To learn more, watch this video.
Now you know the basics of selecting attachments for Composition shingle roofs. Next month, we will explore attachments made specifically for tile roofing. Thanks for following this series, and please reach out with any questions you might have pertaining to products and/or the installation process.