How solar is installed on clay tile roofs
Clay tile roofs dominate the landscape across the American southwest. They look great, are part of Spanish culture, and can last a century. However, they can be a pain in the butt for solar installers to work with.
Until recently, installing solar on clay tiled roofs has been a more expensive and risky endeavor than other roof types, like composite shingle or metal. This is because tiles are relatively expensive, fragile, and removing them to install roof mounts for solar panels can open up the seal of your roof to water damage.
By no means should you let these challenges dissuade you from going solar if you have a clay tile roof. In this article, we’ll review the best installation practices and equipment for clay tile roofs and highlight some considerations when working with your solar installer to upgrade your tile roof home with solar energy.
Installing solar on clay tile will be more expensive
Roof tiles are brittle. Any time someone needs to go up on one of these roofs to get some work done there’s a good chance a few tiles will break. Fitting the right kind of tile back in place of a broken tile isn’t always a quick process, and some tiles can be quite expensive to source.
For these reasons, most solar installers will be a lot more careful when working on a clay tile roof. However, that means they will be slower, and that means you’ll have to spend a little more for labor hours.
Try to avoid “comp-outs” or tile cutting for your on your clay tile roof when installing solar
Some solar installers like to use a technique called a “comp-out” to more easily install solar on clay tile roofs. This technique involves removing all the clay tiles under the area where your solar panels will go, installing composite shingle in this area, then plopping in traditional solar roof mounts, rails and panels in that location.
Solar installers will then go ahead and place similar shaped tiles in between the rows of panels in your array to make things look all tidy again.
Alternatively, some installers attach solar racks to your tile roof by taking out individual tiles and cutting or drilling small holes in them. This allows them to punch the solar mounts through and bolt directly to the wood sheathing underneath the tile.
Going these routes can create some problems, since there will be a slight gap where the tiles used to be and where your solar panels now are. Even though your new shingles protect your roof in the area they were installed in the case of a comp-out, water will still run off of them and sneak below your tile on the lower part of your roof. Further, small holes in your roofing tiles are not ideal for leakage either.
We all know water underneath your roofing material is a bad situation, it can be particularly worse if you live in a location which regularly gets below freezing, as trapped water converting to ice and back again can wreak havoc on your structure. For these reasons, we recommend against these two installation methods for clay tile roofs.
What is the best way to install solar on a tile roof?
For concrete tiles, a solid solar installer will temporarily remove just a few tiles just where special hooks need to be installed into your roof joists. Then, they will install base plates onto your roof membrane, and attach special hooks to them.
Flashing is installed next, preferably with tar, on top of the hook to ensure no water gets into this newly drilled area used to fasten the baseplate and hook (see the image above). Rails are then attached to each hook and your solar panels are mounted to them.
If a baseplate and hook needs to be installed in an area with no accessible roof joist underneath, your installer will need to cut some wood and install it in your attic in the appropriate areas.
Quick Mount PV has many different types of mounts for concrete tile roofs to fit many different tile shapes. Here’s a great video which shows how tile hooks are installed on your roof.
For clay tile roofs, it’s recommended to use a double flashing method instead of using hooks. That’s because the panels and hooks they’re attached to can rattle a bit in the wind and crack the more fragile clay tile. If the shape of your clay tile matches the shape of one of Quick Mount’s tile replacement options, that could be a good alternative as well.
A relatively new innovation, tile replacement mounts, make solar installs easier by reducing your installer’s need to creatively cut tile to fit around hooks. They take the place of the tile under your solar installation where your mounts are attached to your roof! Here’s a video of what they look like:
What does the future of clay tile solar look like?
If aesthetics are important to you and you have a lot of cash to devote to this kind of installation, they may be worth a look. Regardless it’s a wise idea to see how much you can save by starting today with regular solar panels tied into your clay roof using the method outlined above.
Author: Dan Hahn | Solar Journalist
Dan is a solar journalist and content advisor with SolarReviews. He also works with solar installers and solar nonprofits to develop and execute strategic plans.