Choosing equipment is one of the bigger challenges for do it yourself solar installers. Roof attachments seem like a minor part of the system because they don’t cost much compared to the solar panels and inverters but choosing the right ones is very important. It all starts with what kind of roof you have.
The most common residential roof material would be composition shingle, so we’ll start with that. The best options will have a flashing that is at least 12” long so that when you slide it up under the shingles, it reaches the third course above the hole that you are making. There are many brands out there, but one industry staple is the tried and true QuickMount PV. There are other options available for shingle roofs that don’t include that 12” long shingle flashing but it should be said that just because someone makes something and sells it as a solar roof attachment doesn’t automatically mean it is a good option.
Tile roofs are common in places like southern California. There are many different styles of roof attachments that can be used on a tile roof. One of the more popular options is a tile roof hook. This is just want it sounds like, it is a hook-shaped pieces of metal that is lag screwed into the rafter and then hooks up around the edge of the tile so you can bolt your racking to it. What you have to keep in mind here is that the paper that is under the tile is the real waterproofing so that is where you need a flashing so many companies (but not all) include a low profile flashing that sits under the tile and provides flashing for the hole in the paper. If you don’t get the flashing with the tile hook, you can buy them separately.
Another common option is the tile replacement mounts. There are made in different styles to match S-Tiles, W-Tiles or Flat tiles. The handy thing about these is that they do actually replace the tile so you end up with a few extra tiles that you can use in case you break some tiles during the solar installation process.
Finally, there are universal tile mount kits that include a small flashing for the paper and a large malleable flashing to flash the tile layer. The up side on these is that they will work with any style of tile and are especially useful if you have non-standard shaped, low profile tiles. The down side on them is that you will need to cut holes or notches in your tile for the standoff to come up through which can be time-consuming.
Flat roofs have many options. If you want to go with the more traditional stand-off and flashing method, the flashing will depend on the roof material. There is Thermoplastic Polyolefin which is so hard to sat that it is universally called TPO. This is a white plastic material. The flashing for this would be made of the same TPO material and it is heat welded down to the roof with a heat gun. You can buy these flashings pre-made in cone shapes or you can buy flat pieces of TPO and make it into cones yourself. Rolled comp roofing can be flashed with the same type of metal flashing you would use on a shingle roof but then you are limited to having to put the flashings at the seams so you can get up under it without cutting into the roofing material. For a hot mop roof, the flashings can be hot mopped in if you are re-doing the roof or you can use a torch to just work the area where you are installing the flashing.
For almost any flat roofing material, there is also a less traditional option of Chem-curb flashings. These are basically a bowl that goes around your stand-off. Once they are in place, you pour liquid sealant in to fill them. Once the liquid sets, it provides a strong barrier to keep water away from the stand-off penetration.
On flat roofs, you also have the option to not make roof penetration and go with a ballasted system. Ballasted racking systems include trays where you will stack concrete paving blocks that will weigh the system down and keep it in place. The good thing about ballasted systems are that you eliminate the risk of a roof penetration leaking, but you are also adding a lot of weight to the system and you will have to make sure that the structure can handle that extra weight.
Metal roofs are difficult to flash because there aren’t horizontal seams that you can slide a flashing under like you can on a shingle roof. There are hanger bolts with rubber-backed metal washers that provide the water proofing when tightened down properly. There are also stand-offs with EDPM gaskets built into the bottom that will seal the penetration. If the roof is standing seam, you can also choose S-5 clamps that hold onto the seams between the roof panels instead of making roof penetrations. These clamps are very specific depending on the shape of your seams so you have to make sure you get the right ones for your roof. S-5 also makes brackets that can be screwed into the ridges of trapezoidal metal roofs.
There is a lot to consider when it comes to roof attachments, but when in doubt, just call the experts at GoGreenSolar.com and they will walk you through the process of choosing the right roof attachments for your home no matter what type of roofing material you have.