How you mount your solar panels to your roof is one of the most critical steps to having a long lasting solar energy system.
Mounting systems installed correctly will protect your roof from leaks, wear and tear, and secure your solar array to the structure of the house to account for local wind conditions.
Structural Attachments for Solar on the Roof
There are scores of products available to mount solar panels to a roof. The vast majority attach to the structural members (like rafters) of the building using a stanchion or “standoff.” The stanchions are then flashed to prevent water from leaking into the building.
If you’re installing solar panels for your home, you’ll most likely see self-flashing units that combine the structural attachment with the water proofing layer.
For most installations it’s necessary to attach to the structural members below the roof. First, this helps to distribute the weight across the structure. Second, this helps to secure the array to the roof in high winds.
Just by following the instructions for the mounting product will usually protect an installation up to 90mph winds (our building code is 85mph in most of Washington) though often times your system will be protected up to 110-120mph winds. Most racking and panel manufacturers design and test their equipment for loads similar to 125mph (learn more from the Department of Energy.)
Waterproofing
All roof penetrations (think plumbing vents, chimneys, etc.) use flashing systems to help water flow around and away from holes in the roof. We use similar systems in installing solar panels. Many of the self-flashing type attachments like those above will actually have a longer life-span due to their all-aluminum construction. Many standard flashing products used around plumbing vents use neoprene or plastics that break down with exposure to UV.
Every penetration gets sealed with a sealant that is compatible with your roof type, then covered with a flashing, and finally covered with the panels themselves.
If you have a standing seam metal roof, you can likely use a mounting system that allows for zero penetrations to the roof. With standing seams we can often use clamps that grab onto the ribs without ever putting a hole through the roof.
Maintenance
There is very little maintenance to do to the mounting system of your solar power system. The most important thing is to look under your array.
Make sure there are no “debris dams” that is, no branches, pine needles, squirrel nests, or other piles of junk hanging out under there. These dams can allow water to push up under flashing systems and even shingles allowing water to get to the structure below.