Solar site survey tools: the field kit, by what it measures

The kit board: what each tool actually measures

Hover or tap a tool. The house lights up where that tool does its work, and the readout names the error it exists to prevent.

Tape, laser and pitch gauge: the numbers the layout sits on

Tape measure and laser measure

Measures: plane length at the eave, rake and ridge, and the offset from each obstruction to the nearest edge. Prevents: a layout drawn on traced geometry. Overhangs, gutters and parallax hide the true plane edge in imagery, and a plane a foot shorter than the drawing can lose a row of modules.

Carry both. A long tape run from eave to ridge on the plane itself is the reference you trust, and it doubles as a known scale for any photo-based model. A laser measure is faster for eave-to-eave runs from the ground or across a plane you cannot safely walk. When the two disagree, re-shoot before you climb down.

Pitch gauge or digital inclinometer

Measures: the slope of each plane. Prevents: a production estimate and a wind and snow check built on the wrong angle. Read the gauge seated on the plane, not on a ridge cap or a raised shingle edge, and read every plane: additions and dormers rarely match the main roof.

Compass and shade tool: where the sun actually lands

Compass or calibrated orientation tool

Measures: the azimuth each plane faces. Prevents: a production estimate pointed the wrong way. Two things trip technicians up. First, a magnetic compass reads magnetic north, while design tools generally expect true north. The difference, magnetic declination, depends on where you are and can run past ten degrees in parts of the United States. NOAA publishes a declination calculator; note which reference your reading uses. Second, a phone compass is easily pulled off by flashing, vents, a metal roof or the service panel. Take the reading away from metal and sanity-check it against the street grid.

Shade or horizon tool

Measures: the obstructions on the horizon, as seen from each array area. Prevents: a shade loss that nobody saw coming. The rule that matters is location, not the device: capture from each proposed array area, not once from the middle of the roof. A tree that shades the west plane can be invisible from the east one. Note whether each tree is on the property, and flag near obstructions that only matter in winter, like a chimney or a taller neighbour. Our shading analysis page shows what that capture becomes.

Attic kit: a light, a tape and a way to read the framing

Measures: rafter or truss depth and width, on-centre spacing, span, and sheathing type. Prevents: a structural letter written against assumed framing. The engineer cannot see through the roof, and neither can a drone. This is the one input that has to be read by hand.

The kit is small: a headlamp and a handheld light, a tape, knee pads, and a board to walk on across the joists. Measure the actual depth of the member, hooked to the underside of the sheathing, because a nominal 2x6 is about 5½ inches deep and older framing does not always match modern lumber. Lay the tape across several bays to confirm spacing, since 16 and 24 inches on centre look similar in a dim attic and change the attachment layout. Photograph anything that limits attachment: ducts, an air handler, junction boxes, sagging or damaged members. See the attic and structure page for how we record it.

Electrical PPE, a meter and a photo checklist

Measures: the main breaker and busbar ratings, open slots, service size, meter details and the grounding path. Prevents: a common and avoidable redesign: a plan set drawn against a busbar rating nobody verified. The main breaker and the busbar are often rated differently, and the busbar is the number the interconnection math is checked against.

Treat the electrical kit as three parts. PPE sized to your company's electrical safety program: safety glasses, voltage-rated gloves where required, and arc-rated clothing if the task calls for it. Only a qualified person removes a dead front. A meter rated for the measurement category of the equipment it will touch, if your program allows live verification at all. Many survey programs are photo-only. A photo checklist, which does more work than either: the panel label, the main breaker, the busbar rating, the full interior with every breaker legible, the meter number and the service entrance. The electrical and interconnection page shows the full shot list.

Ladder and fall protection: the tools that keep the survey possible

Measures: nothing. Prevents: the worst outcome on any job, and a survey that stops at the gutter because nobody could get on the roof safely. For residential construction, OSHA 1926.501(b)(13) requires guardrails, a safety net or a personal fall arrest system at 6 feet or more above a lower level, with a written fall protection plan allowed only where those are shown to be infeasible. Whether a given survey is treated as construction or general industry work is worth confirming with your safety lead.

For ladders, OSHA 1926.1053 calls for side rails that extend at least 3 feet above the landing and a setup angle where the base sits about a quarter of the working length out from the support. In practice the kit is a ladder tall enough for the two-storey jobs, a ladder stabiliser or standoff so it does not bear on the gutter, a harness and lanyard, and a roof anchor. Record the ladder point you used: the install crew needs it too.

Drone and phone: capture tools, not decoration

Drone for measurement photos

Measures: nothing directly. It captures the overlapping photos a dimensioned roof model is built from, plus the planes and obstructions you cannot safely walk. Prevents: a missing plane or an unmeasured steep face. The photos only become measurements with a known scale, which is why the tape run on the roof still matters. Commercial drone work in the United States also requires an FAA remote pilot certificate under Part 107.

Phone or tablet capture app

Measures: it records everything else. Prevents: the return visit. The capture app is where the checklist lives, and its most important feature is the review step: every photo checked on the device before the truck leaves. Blurry, dark and cropped-too-tight are recoverable on site and expensive afterwards.

The solar surveyor kit list, in one table

Check it before the first job of the day.

How we run the kit

Our site survey puts one technician on the roof, in the attic and at the service panel in one visit, with the deliverable back within 48 hours. The zone pages show the kit at work: roof and drone capture, attic and structure, and electrical and interconnection.

Questions technicians ask