Roof Mount System

A roof mount system is the most common type of residential solar installation, with panels attached to the home’s roof using a racking system secured to the roof structure. Over 90% of residential solar installations in the US are roof-mounted.

Roof mount systems are popular because they use existing space (your roof) without requiring additional land, keep panels out of the way, and are generally less expensive to install than ground-mount alternatives. The racking is attached to the roof rafters or trusses using lag bolts and sealed with flashing to prevent leaks. Panels are positioned a few inches above the roof surface to allow airflow for cooling. The ideal roof for solar is south-facing with a pitch of 15°–40°, minimal shading, and made of composition shingle, standing seam metal, or concrete tile. Flat roofs use ballasted or tilted racking to achieve an optimal angle. Roof condition is important — if your roof needs replacement within the next 5–10 years, it’s best to re-roof before the solar installation to avoid the cost of removing and reinstalling panels later. Most roof mount installations can be completed in 1–2 days.