Why a lot survey is not a roof survey
Rooftop solar borrows an existing structure. Carports and ground mounts have to build one. That shifts the survey from checking an existing roof to understanding a piece of land: what is above it, what is under it, who else has rights to it, and how power will get from the array to the building. The questions are different, and so is the cost of getting them wrong, because foundations, trenching and structural steel cannot be moved after they are installed.
Many commercial projects scope a carport or ground mount because the roof fell short, either structurally, because of warranty limits, or because of age. Our note on roof structural assessment for commercial solar describes when that happens. In those cases the lot survey should be scheduled alongside the roof visit, not after it.
Boundaries, setbacks and easements
Start with what the owner can legally build on. Record the property boundary as best the available documents allow, building setbacks, utility and access easements, and any restrictions from the zoning authority or a landlord. A boundary survey is a different, licensed discipline, so treat site measurements as design inputs rather than a legal boundary determination, and request the owner's recorded survey or plat where one exists.
- Property lines, setbacks and easements from the owner's documents.
- Lease terms or landlord approvals if the owner does not control the land.
- Zoning or parking requirements that limit removing stalls.
- Landscaping, trees and signage that would be removed or shaded.
Underground utilities
Underground conflicts are the quiet budget killer on carports and ground mounts. Every foundation and trench has to avoid water, sewer, storm drain, gas, electric, communications and irrigation lines. The survey should record every surface indicator: manholes, valve boxes, cleanouts, light pole bases, junction boxes, marked paint and patched asphalt. The owner or facilities team can often provide as-built utility drawings. Before any digging, the project must also use the standard one-call utility locating service, and the survey is the right moment to flag areas that will need private locating.
Grade, drainage and soils
Photograph and measure slope across the proposed footprint. Parking lots are graded to shed water, and a carport structure sits on that grade, so column heights vary. Note drains, curbs, bollards, swales and where stormwater goes. For a ground mount, record vegetation, standing water, visible rock and evidence of erosion.
Soil data drives foundation design, but the survey does not replace a geotechnical investigation. What it should do is flag the need: filled ground, previous excavations, high groundwater indicators, expansive clay or shallow rock. The engineer can then decide what geotechnical work is required before foundations are specified.
Parking, traffic and clearances
A carport is a structure over cars and trucks. Measure stall dimensions, drive aisles, turning paths for delivery vehicles and the heights of vehicles that actually use the lot, including any vans, box trucks or fire apparatus. Record lighting, cameras and signage that will have to be relocated. Record existing EV charging or planned positions, because carport canopies and charging are frequently designed together.
Fire access and safety
Fire departments care about access to buildings and to hydrants, and ground-mount arrays often face their own setback and vegetation rules. Record fire lanes, hydrant locations, the fire department connection and gates. Note the adopted code edition and any requirement the owner already knows about, because local amendments differ. Rapid shutdown also applies differently to carports and ground mounts than to rooftop systems, and which edition of the electrical code applies depends on what the jurisdiction has adopted.
The conduit route back to the building
Measure the route from the array to the inverter location and onward to the point of interconnection. A carport at the far end of a lot means a long trench across the paving, with saw cutting, restoration and utility crossings. The engineer needs actual lengths and crossing points, and the cost estimate depends on them. Also photograph the switchgear and capture the items in our note on electrical service and interconnection survey items, because a ground mount feeding a distant switchboard may suit a different interconnection approach.
Why structure type changes what you capture
Carports and ground mounts differ in ways that change the survey. A carport canopy is a structural frame, usually on drilled pier foundations, whose columns land between parking stalls. The survey must therefore capture stall layout precisely, because column positions are chosen to fit it. A fixed-tilt ground mount typically uses driven piles or ballasted foundations, so surface conditions, rock indicators and access for piling equipment matter more. A tracker adds further requirements, including level ground and clear room for the array to rotate.
Think too about the people who use the site. A carport over a busy customer lot changes how people drive, park and walk, and a ground mount may change how groundskeepers mow and how water leaves the property. Ask the owner who uses the space and when, so the construction plan can avoid blocking the entrance or loading areas during business hours. These operating details are the most common reason a technically sound carport design is revised late, and they are free to collect during the survey.
Finally, ask whether the owner expects future changes to the lot, such as an expansion, repaving or EV charging, so the layout does not box in the next project.
Deliverables for carports and ground mounts
- A dimensioned site plan with boundaries, setbacks, existing structures, parking layout and the proposed footprint.
- A utility conflict map with every surface indicator located.
- Grade and drainage notes, with photographs from several viewpoints.
- A trench route with lengths and crossings.
- Access, staging, crane or drill-rig access, and neighbor or tenant constraints.
Solar Survey AI performs on-site commercial surveys across the country, with the deliverable 48 hours after the survey. For larger land-based projects, our utility-scale work covers topography and construction monitoring, and a commercial on-site survey can be scoped to include the lot as well as the roof.