Solar panels are attached to the roof in a fairly straightforward manner, although there are some careful considerations that must be addressed to ensure safety and durability. In essence, the panels are simply bolted to the rafters in your roof system. Typically, the actual panels sit in a rack-mount system, which attaches to the roof via bolted-down brackets.
Critical Installation Issues
The most prevalent issue with solar panels is not their weight or the threat of collapsing the roof (although structural considerations must be taken), but the “uplift” or “upforce” caused by wind blowing up and under the panels. Therefore, it is vital that the bolts are screwed into the center of the rafters and not simply the plywood sheathing, or shell, of the roof. A good solar installer will take pains to find the exact center of the rafters before installation.
Variations based on Roof Type
Of course, installation on a flat roof will be different because a scaffold system will have to be built to achieve the desired panel tilt. Cost and time for installation will also vary based on the type of roof you have. For instance, tile roofs will likely cost more and take more time because of the tiles’ fragility and the time it takes to drill through the tiles. Composite, or asphalt, roofs are usually the easiest to install panels on.
The installation described above is for traditional, 1st generation, photovoltaic panels. Thin-film, 2nd generation solar panels are flexible and install much easier. Some types of solar shingles attach just like traditional, composite roof shingles. As solar panel technology changes, so installation techniques will change along with it.