Tile roofs have a long history of being more complicated and challenging for solar installations than on any other residential roof type, especially on a retrofit job. Depending on the age of the building, tile roofs can vary in their construction, materials, and approach for solar mounting. It is this reason that there are so many different ways to mount solar to the roof. While there are tile mounts that are considered “universal” and can be applied to most tile roofs, there really is no single product that every solar installer in the US prefers to use for all applications, in all regions. Tile roof construction also differs on a regional basis. To break this down and have a better sense of these challenges, we’ll go over the basics of tile roofing, mounting types, and the products K2 has to offer to point you in the right direction for your mounting needs.
In the early 1980s tile roof construction guidelines took an important shift that is critical to understand for solar installers stepping foot onto any existing tile roof. Prior to the 1980s, tile roofs were commonly built with skip sheathing and direct attached tiles. After water intrusion issues, tile roofs were then required to have solid sheathing, underlayment (as a water barrier) and then tiles over the top.
This means that installers would encounter both types and even some that have both skip sheathing and plywood over the top as a code update or roof upgrade. Over the years, I’ve been contacted many times by installers sending me a picture like this, asking: “What do I do here?” My answer is usually “Run away!”
Kidding aside, the best answer for an outdated roof system is to find a qualified roofer who knows these types of tile roofs. If that is not you or someone within your company then it’s always a good idea to have a relationship with a local roofer who you can contract out mounting for complicated roofs, make roof repairs, and/or consult on roofs that are a questionable fit for a PV solar installation. Chances are the homeowner is due for a roof upgrade anyways. The best time to upgrade a roof is before solar is installed. The more you work with tile roofs the more you see patterns in regional construction types and know when it might be best to call in your roofing partner. Most modern tile roofs now have been standardized to have solid decking/sheathing, underlayment that is either felt paper, a synthetic water barrier, or an adhesive underlayment (common in FL) and then tiles over the top.
While you may run into various old or odd-ball tiles such as cap & barrel, Spanish clay, asbestos, plastic, or even porcelain, the most common tiles today consist of 3 main concrete tile profiles: Flat tile, S-tile, and W-tile.
These concrete tiles are interlocked with what is typically called a cap and pan on the side of the tile to hook and connect them all together across each row. Attaching the tile to the roof varies based on regional conditions. In Northern California and most of Arizona the tiles are hooked onto a wood batten like you see here.
The battens allow the tiles to hang and not require individual attachment points, aside from the perimeter/edge tiles. Whereas in Southern California most of the tiles are attached with nails through each individual tile to the decking, eliminating the need for battens altogether. In Florida, where there are higher wind speeds and hurricane requirements, tiles are often adhered to the roof with concrete mortar or a foam adhesive. These types of roofing can be found all over the US, but you’ll see a dominating trend in various cities and states. Getting more familiar with these types of roofing methods in your area will help you and your team understand how to remove tiles and what mounts may be best for your racking system.
As an international company with installations all over the world, K2 Systems has an extensive background mounting solar to various tile roof types. The most commonly used solar mounting system for tile roofs has been tile hooks.
The tile hook allows you to attach the structure of the building and curve out and over the tile to support the racking system while showing minimal hardware. This can be done with or without a tile flashing, making it a simple installation with better aesthetics. In the past it was very common to install the tile hook and grind the underside of the tile just enough to allow the hook to pass through the tile and allow it to sit in its original place. Due to OSHA safety concerns and regulations on dust particles created by tile cutting and grinding, installers now use metal replacement flashings that resemble tiles and seamlessly install the tile hooks.
Tiles come in many shapes and sizes. Solar installers have different needs for regional conditions like wind and snow. That, combined with the cost competitive nature of the solar industry attempting to keeps costs low, results in manufacturers needing to have various tile mounting options. Based on customer feedback and needs, K2 has developed a wide variety of hooks with different features to choose from.
For roofs with higher wind speeds and/or snow loads, K2 has developed a series of higher performing tile hooks with more material and strong engineering load capacity. The 3S Hook, a product that originated from K2’s headquarters in Germany, has a robust aluminum base and hook that allows for lateral and vertical height adjustability. It features a hook that returns over the tile placing the load weight closer to the attachment points and connecting the rail to a traditional L foot. This creates a stronger hook that avoids deflection in the hook arm and also allows for maximum adjustability.
Adapting to the American solar market, K2 US has recently designed the 3L hook, which is slated for release in late Q2. This product takes the adjustable features of the 3S Hook and simplifies the mount-to-rail connection by eliminating the L foot. It also includes built-in water diversion walls that protect the roof penetration sealing washers from direct contact with water coming down the roof surface. This eliminates the need for excess sealant over the lag screws.
Also originating in Germany, the Flat Tile Hook was released in the US in 2019. Flat tile roofs are considered to be one of the most common concrete tile roofs in the US. Due to their strength and simplicity, they can be found in unlikely areas with snow, such as Colorado, Oregon, and even parts of the Midwest. This creates the need for a stronger hook that can withstand more deflection than common steal hooks that are used in more typical tile states like California and Arizona. The K2 Flat Tile Hook has a simple design that is short, stocky, and robust. The hook arm has a profile that tapers upward in order to withstand more load pressure from above and not come into contact with the tiles below.
K2 US has recently released a new hook called the Flat Tile Hook X. This hook is designed with a longer and more straightforward reach that allows the hook arm to extend out further for bigger tiles. This product is a part of a new series of steel hooks that are cost effective and simple for markets that have lower wind and snow loads. For S-tile, W-tile, and other non-flat tile roofs, K2 US and Mexico offers 2 adjustable hooks that are universal.
The Universal Standard Hook, 9” Base is a simple one-piece welded steal hook with a wide base for connecting to rafters and allowing the hook to protrude out in the valley of curved tile profiles. Similarly in function, the Universal Standard Hook +2, 5.5 Base is a two-piece steel hook that allows for more adjustability by allowing the hook arm to be bolted to 3 locations on the base plate.
This series of flashings is designed for common flat tile, S-tile, and W-tile profiles. Simple, yet innovative, these replacement tile flashings are extremely easy to install with features that slip and lock into the tiles. Unlike other replacement tile products, these flashings are designed without cap and pan interlocking sides that often cause problems with uneven roofs surfaces. When cap and pan style flashing interlock similarly to tiles, the weight of the tiles can cause the bottom row of flashings to curl upward.
This not only creates an eye sore to the aesthetics of the roof, but it also creates an invitation for water, debris, and animal nesting. To avoid these issues the EverFlash Tile Replacement Flashings from K2 have a cap on both sides with a wider flashing to cover the full extent of the tile. This installation process is much easier and only requires lifting the top row of tiles just enough to slip the flashing into place, whereas cap and pan style flashing need the side tile to be lifted and interlocked. A second feature that keeps the flashing in place are the built-in secure tabs on each side of the flashing. This feature allows for two additional securement points on each corner of the tile, locking it into place. Tabs on the face of the S-tile and W-tile allow for hooks to easily pass through without the need for cutting.
The complexity that can sometimes come from tile roofs proposes potential problems that beg to be solved by simple solutions. The international experience that comes with K2 Systems allows us to provide simple and innovative product designs that can solve these problems in California, Florida and every state in-between.
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