Solar Panels on Flat Roofs

Frames, not rails

Panels sit on a ballasted or tilted frame set on the roof surface, angled to catch more sun. In most cases nothing penetrates the membrane at all, which is exactly what you want on a flat roof.

Ballast and wind loading

The frame is held down by weight and by aerodynamics. Both the ballast and the wind loading have to be calculated, and the roof structure has to be able to carry the result. This is the first thing a competent installer will look at.

Membrane condition

A flat roof near the end of its life should be recovered before an array goes on it. Protection pads or slip sheets go under the frame to protect the membrane.

Layout

Tilted rows shade each other if they are too close, so row spacing costs you area. A flat roof usually fits fewer panels than its square meterage suggests.