Updated 2026 — Flat-roof mounting comes down to two calls: how the array holds down (ballast vs. fixed) and what the roof can carry per bay. Solaracks answers both with a stamped calc, then ships from nine SR-B systems — start with the flat-roof range or the zero-penetration SR-B1 “Duck”.
What is Flat Roof Mounting System?
Flat Roof Mounting
The flat roof configuration offers stability and maneuverability in the selection of orientation and tilt, although it is generally the considered option for commercial roof mounted, it is also possible to implement it in the residential sector if the roof is flat. This type of system involves the design of a ballasted concrete structure (just like in-ground mount) that enables the modules to be placed at a specific tilt. Solar panels can be fastened to the concrete base, saving costs of metal materials for the mounting structure. If the system has a solar tracking design, then the base for the aluminum structure is fixed to the concrete while at the same time providing mobility for the solar panels. The typical selections in average households are roof-mounted systems, which provide security to the system, fewer shading obstacles, roof protection and are generally more economical than ground mounted systems.What is Flat Roof Racking System?
Major types in roof-mounted solar racking systems
Ballasted or penetrating: how to choose
On a flat commercial roof the first decision is whether the array resists wind uplift by weight (ballast) or by fixing into the structure (penetrating). Ballasted systems keep the membrane intact and install fast, but they add dead load — typically 10–25 kg/m² depending on wind zone, building height and parapet. Penetrating systems carry almost no extra weight and suit high-wind or lightweight roofs, but every attachment must be flashed and warranted by the roofer. Many projects use a hybrid: mostly ballast, with mechanical anchors added at the perimeter and corner zones where uplift peaks.
What sets the ballast weight
- Design wind speed and exposure — the governing input; corner and edge zones (ASCE 7 / EN 1991-1-4) need more ballast than the field.
- Tilt and row spacing — higher tilt catches more wind and needs more hold-down or wind deflectors.
- Roof height and parapet — taller buildings and low parapets increase uplift.
- Allowable roof load — the ballast plan must stay within what the structure carries per bay, which is why a stamped calc matters.
Solaracks returns a per-project ballast layout and load calc with every flat-roof quote, so the numbers are checked against your actual roof before anything ships. Send your roof details for a layout and calc.
