what it is
Solar for Low-Slope Roofs
Warehouses, offices, retail buildings, and industrial facilities often have exactly what solar needs most: large, open, low-slope roof area. Flat-roof commercial solar turns that space into an on-site power plant.
Commercial roofs are different from residential ones. The roof membrane, the structure underneath, the drainage layout, and the equipment already up there (HVAC units, vents, skylights) all shape the design. We build the system around the roof you have — not the other way around.
Ballasted vs. Attached Systems
There are two general approaches to mounting panels on a low-slope roof:
Ballasted Systems
Ballasted arrays are held in place by weighted blocks rather than roof penetrations. Panels sit on racking that rests on the roof surface, with weight keeping everything stable against wind. This approach avoids puncturing the membrane — a real advantage on roofs where waterproofing is the priority — but it adds distributed load that the structure must be able to carry.
Attached Systems
Attached arrays fasten directly to the roof structure with engineered penetrations that are flashed and sealed. They're typically lighter than ballasted systems and work well where the structure needs less added weight or where wind conditions demand a mechanical connection. The tradeoff is penetrations in the membrane, which must be detailed and warranted correctly.
Which approach fits your building depends on the roof membrane, the structural capacity, wind exposure, and the condition of the roof. We evaluate all of it during the site assessment and recommend the method that fits — not a one-size-fits-all default.
Roof Condition Comes First
Solar panels last for decades, and they should never go on a roof that won't. Before we design a system, we look hard at the roof itself:
- Membrane condition. Age, wear, ponding areas, and prior repairs tell us whether the roof is ready for an array — or whether roof work should happen first.
- Structural capacity. The structure must carry the added load of panels, racking, and ballast (if used). We recommend a structural assessment before finalizing any design.
- Remaining roof life. If the roof is near the end of its life, it's usually smarter to re-roof first than to install panels and remove them later. Our sister company Bright Roofing handles roof repair and replacement — and our solar-and-roofing page explains how to sequence the two projects.
Minimal Disruption
Your building keeps running while we install. Commercial installs are planned around your operations: staging areas and material deliveries are coordinated with building management, noisy work is scheduled for appropriate hours, and the array layout works around rooftop equipment and maintenance access. Most of the project happens on the roof, away from your daily business.
Frequently Asked Questions
Will Installing Solar Damage Our Roof?
Done right, no. Ballasted systems avoid penetrations entirely; attached systems use engineered, flashed penetrations designed for the specific membrane. The bigger risk is putting panels on a roof that's already failing — which is why we assess roof condition before designing anything.
Does Our Roof Need to Be Replaced before Adding Solar?
Not always — but if the roof is near the end of its service life, re-roofing first is usually the right call. Removing and reinstalling an array for a later roof replacement costs far more than doing the roof work up front. If roof work is needed, our sister company Bright Roofing can handle it.
How Do You Decide between Ballasted and Attached Mounting?
Based on the roof membrane type, structural load capacity, wind exposure, and the roof's condition. Ballasted avoids penetrations but adds weight; attached is lighter but penetrates the membrane. We recommend the approach that fits your specific building after the structural and roof assessment.
Can You Install While Our Business Stays Open?
Yes — that's the norm for commercial projects. Work is staged on the roof and coordinated with building management so daily operations continue. We'll plan delivery routes, work hours, and equipment staging around your schedule.