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Flashing and Mounting Solutions for Shingled Roofs

Here are some options for protecting the point where the solar racking attaches to a pitched roof in a PV installation involving shingles.

The racking and mounting system of a solar PV installation normally consist of 10% to 25% of the total cost of the installation. However, the related roof maintenance costs are rarely included in the solar PV financial calculations. All the racking equipment requires roof penetration which can lead to water leaks and also may void the roof warranty. To avoid such costly mistakes the solar PV system should be installed according to municipal code and installation manuals.

Thus, installers and homeowners must be cautious in regards to which roof mounting systems they select. 

There are four important measures for selecting a roof mounting system:

  1. The cost of the system: The lower, the better.
  2. The life-span and reliability: The mounting system must last for at least 25 years. (which is the normal life span of a solar PV installation)
  3. Ease of mounting: The installation may take a long time relevant to the rest of the project and can require high attention to detail. These circumstances can increase labor costs and may result in improper installation.
  4. Code compliance: The use of flashings may be necessary for the system to not cause any water leaks or electricity grounding hazards.

I have conducted some brief research on flashings and mounting solutions available on the market. CivicSolar carries most roof mounting solutions, so you can do your own comparison here. The below table represents a brief comparison of the flashings and attachments.

Because of the variety of styles and additional considerations necessary, I do not take rails and racking equipments into consideration. That is a topic on its own. The items that I compare are the pieces of equipment between the rails and the roofing, where the actual attachment happens.

 

Unirac

Aluminum

Unirac

Galvanized Steel

Prosolar 

FastJack

Quick Mount PV

Schuco

ezStand-off

TTI 

FlatJack

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Required Extra FlashingFlashing for 1/2" - 1-1/8" O.D. shaftFlashing for 1/2" - 1-1/8" O.D. shaftFlashing for 1" O.D. shaftIncludedezFlush-Mount FlashingIncluded
Required Extra HardwareIncludedIncludedIncludedIncludedIncluded5/16" lag screws
Ease of InstallationEasy to ModerateModerateEasy to ModerateVery EasyEasyEasy
Code ComplianceCompliant with flashingCompliant with flashingCompliant with flashingCompliantCompliant with flashingCompliant
Product CostLowLowLowestMediumLow to MediumLow to Medium

Comments

Thanks for the great article.  Question.   Does the flashing for the solar panel racking need to be installed by a licensed roofer in order to maintain the warranty for the roof?

I believe having the roofer on site during the installation is the most advisable method, so that the roofer can take care of the flashings before the racking is installed.

As long as the installation is made by complying to roof material instructions, the warranty would maintain.

The chapter 15 of International Building Code is reserved for roof assemblies. In the article #1507, it mentions "flashing and counter flashing shall be provided in accordance with the manufacture's written installation instructions, and where of metal, shall not be less than 0.019 inch (0.48mm) (No, 26 galvanized sheet gage) corrosion- resistant metal"

Thanks for this clarification as there is a lot of confusion around existing roof warranties as it relates to installing solar racking.  

I've found the IBC (the building code) for California online.

It's a 60MB .pdf document with 766 pages, takes time to download, but very helpful reference. The instructions about water proofing are under section #1503.

You have mentioned very important points. I have heard about this topic but this is the first site I got to read about this topic. Solar PV roof mount will help to reduce use of electricity and it will save the energy.