Attachment, especially for life, can prove to be difficult to achieve in many situations. In the case of solar electric systems, it is literally the mainstay of lasting performance. Very important that we get this part right!
Solar panels are attached to a roof using a racking system. The racking system design will differ depending on whether it is a tile, shingle or flat roof. Attachment points, where the racking is screwed into the roof rafters, must remain waterproof for the 30-year service life of the solar system. This is achieved with designs that include weatherproof washers, adhesives and sealants.
It would be very expensive to remove and reattach the racking and panel in the event of a roof problem. Super important to inspect the roof on which solar is to be installed BEFORE installation and make any necessary repairs first.
Some racking system attachments are made by drilling through the roofing materials, such as asphalt shingles. Others, like cement tile, involve removing a piece of tile and replacing it with metal flashing. This latter is easier to complete, avoids drilling and potentially cracking the tile while providing a better seal around the attachment.
Extra care is required when installing on metal roofs. Foam insulation may be under the metal and subject to crushing unless specific attachment hardware is used. Arrays are also attached directly to the metal roof ridges when the structural strength is sufficient.
Sorry folks, but it is not recommended to even attempt to install solar on a roof with clay tiles. They are simply too fragile for the installer to walk on without causing damage. Enjoy your beautiful roof, but unfortunately, not solar.
Flat roofs can be notorious for leaking, generally because of poor original construction practices. Now imagine drilling several holes into it at the attachment points and hoping for an excellent outcome!
Because of the potential for standing water, the leak-proof attachment design on flat roofs is more robust. This racking has the advantage of being oriented and tilted allowing the solar panels to produce optimal power in a particular location. Recoating of the roof beneath the panels on a routine basis is possible as one end of each panel is up off the roof surface.
For those property owners unable to install solar panels on their roofs, there are other options. If living on a large lot, it may be possible to install a ground-mounted system in a sunny, used portion of the yard. If a shade structure or carport is desired, a purpose-built structure may be the answer for locating solar panels.
Where ever the placement, there is an attachment system available to ensure that the solar panels are securely fastened. And, if on a roof, that it remains free of leaks where the racking has been attached to the rafters. After all, those panels are going to be there for 30 years!