Glass-glass solar carports, pergolas and canopies in New York

Why build solar over unconditioned space

A detached structure over a driveway, patio or parking area avoids roof penetrations and the condition of the existing roof. Outside NYC, detached non-habitable structures such as carports and solar trellises are generally exempt from the roof access pathways that limit arrays on houses, so the full canopy can be used. Bifacial glass-glass modules also collect some light reflected from the ground below.

The structure provides shade and shelter as well as power. For property owners whose house roof is shaded, small or already at its fire code limit, a canopy is often the most practical way to add capacity.

Three ways to build the roof

• Framed modules on a steel or aluminum canopy: the standard approach. The modules sit on purlins, and rain passes between them unless a separate roof is installed below.
• Glass-glass modules on rails, with gaps between modules or a gutter channel under each joint to manage water.
• PV as the roof membrane: sealed or bonded frameless modules that form a watertight roof. This approach turns the module into overhead glazing, which raises additional questions about laminated glass, overhead glazing rules, adhesive approvals and long-term sealant movement.

The third approach is the most attractive and the most demanding. The owner should obtain the module manufacturer's written approval of the mounting or bonding method, since module warranties are generally tied to the installation manual, and the building department decides which glazing provisions apply. No frameless or bonded system should be assumed to be code-approved.

An electrical listing is not a structural approval

Solar modules are listed to UL 61730, or to the older UL 1703. These listings cover electrical safety and fire safety, and they include a mechanical load test at the design load the manufacturer rates the module for, when it is mounted as the installation manual specifies.

A listing is not a building code approval for an overhead roof over people or vehicles. It does not cover the spans of the frame, the clamps or adhesive that hold the module, drifting snow, or what happens to the glass if it breaks. Glass-glass construction improves the module's own load rating, but it does not decide those questions.

For that reason, we treat every solar canopy as an engineered structure, designed by a New York-licensed professional engineer and filed for a building permit.

What the engineer checks

• Snow loads, including drifting, and snow sliding off the canopy onto adjacent roofs, walkways or cars.
• Wind on an open structure, which acts differently from wind on a closed building.
• Clamp positions and attachment zones permitted by the module manual for the chosen module.
• Glass breakage and retention, particularly where people walk or park underneath.
• Foundations, frame members and connections for the loads above.

Spans, member sizes and load values depend on the site, the module and the code edition, and we do not publish rules of thumb for them. They come from the engineer's calculations for each project.

Permits and rules in NYC

In NYC, photovoltaic systems must comply with the Building Code, the Electrical Code, the Zoning Resolution and the Fire Code (BC 3113). The frames of awnings and canopies must be noncombustible and designed for wind and lateral loads under Chapter 16 (BC 3105.3). Where a PV support structure sits on a roof, its frame and the roof construction supporting it must meet the construction-type requirements of Table 601 (BC 1512.1.1). A canopy requires a DOB filing with professional drawings, and zoning and yard rules apply.

On flat roofs, the Fire Code requires a clear path 6 feet wide and 9 feet high, the path surface may not be glass or translucent, and firefighters may not be required to walk on flush-mounted panels (FC 504.4.4). A glass PV roof therefore cannot serve as a walking surface on an NYC rooftop. Raised arrays over the clear path should be discussed with FDNY requirements in mind before design begins.

Permits on Long Island and elsewhere in New York

Outside NYC, a solar canopy or ground-mounted structure requires a building permit from the town or village. Under the Residential Code of New York State, ground-mounted PV is designed to the structural provisions of section R301 and the fire separation distances set by the local jurisdiction. Town zoning governs accessory structure setbacks, lot coverage and height, and these limits stop more Long Island carports than structural issues do. Confirm the zoning requirements with the town before design.

Connecticut, New Jersey and Pennsylvania follow IRC- and IBC-based codes with similar requirements. The local building department is the authority in each case.

Snow, electrical and site details

• Snow shedding: choose the tilt and the low edge so that snow does not slide onto doors, walkways or parked cars.
• Foundations: footings must extend below the local frost depth, which the town building department sets.
• Wiring: conductors under a carport must be protected from vehicles, and trenching to the house is part of the scope.
• Rapid shutdown: NEC 690.12 applies to PV systems on or in buildings, and whether a freestanding carport counts is decided by the building department. We design to the plan examiner's determination.
• Lighting and receptacles under the canopy are wired to code, with GFCI protection where required.

Cost drivers and how we approach a canopy

The main cost drivers are:

• Steel or aluminum framing and its finish.
• Foundations, which depend on soil, frost depth and access for equipment.
• Engineering and permit drawings.
• Crane or lift time to set the frame and the modules.

We check zoning and setbacks, coordinate the engineering for New York snow and wind, and provide one price for the structure, the solar and the permits, with electrical work performed by our licensed partner electricians. A site photo and rough dimensions are enough to begin.