Solar Roof Terms

Solar Roof, Racking, and Mounting Terms: 

Air Gap – The area between the panel and the rooftop, between 6-12 inches, that allows for air to flow over the back side of the panel to prevent overheating and malfunction.

Ballasted Racking – A PV racking design for a tilted array on a flat roof that is not directly mounted into to the rooftop, but rather utilizes weights, cinder block, or sandbags, to hold the framing/racking down to the roof.

Comp-out/Strip and Go – Installation method for clay tile or concrete tile roofs in which the area where the panels will be installed is removed and a layer of composite shingle is laid. The solar system is then installed over the composite shingle and the exposed areas are then relaid with clay or concrete tile.

Composite – A type of roofing shingle that is made of tar paper and covered with asphalt; standard roofing shingle.

Concrete Tile – A roofing material that is made from concrete or cement to form individual tile units.

Flashing – Material that is used on roofing that is waterproof and installed around joints and crevices to prevent water leaks.

Flush Mount – Style of mounting a PV system to a rooftop wherein the system is as close to the roof as possible and nearly eliminates the air gap; usually done for aesthetic purposes.

Footing – The physical part of the racking system that attaches to the roof; a solar array will have multiple footings.

Non-Penetrating Racking – An installation method wherein the racking system does not bore down to the roof beams. Tile hooks or footings that attach to the plywood underboard are used but do not penetrate the larger roof beams.

Re-Roof – The process of installing a new roofing material, which can occur sometimes before a solar installation is performed.

Re-Deck – The process of removing the plywood portions underneath the roofing material; performed if any wood portions are rotted and need to be replaced to support the weight of the solar system.

Ridge – The horizontal area where two roof slopes meet.

Roof Obstructions – Any object on the roof that may not be covered by solar panels, such as a chimney, kitchen vents, and AC units.

Roof Types – The most common roofing materials are concrete tiles, clay tiles, composite shingles, metal tiles, standing metal seam, and a flat roof.

Sealants – A substance used to block any open holes on the roof; to waterproof any open areas.

Set Backs – The distance a solar system must be away from either the roof edge, or certain roof obstructions, such as skylights, chimneys, AC units, and vents.

Stand Offs – An installation method where the solar modules are installed a few inches above the roof plane, but then tilted towards the optimal angle for solar production; used on rooftops that have a shallow incline.

Valley – The point on a roof where two different roof slopes meet, often referred to as “hips and valleys.”