Measuring a jobsite for ornamental metal means capturing four things, not one: the dimensions, the site conditions that affect how the work gets installed, the code requirements that govern what you're allowed to build, and photographic evidence of what the site looked like on the day you were there. Shops that capture only dimensions are the shops making return trips.

The measurement is rarely what goes wrong. What goes wrong is everything around the measurement — the footing nobody checked behind the stone veneer, the guard height that turned out to be commercial instead of residential, the driveway slope that wasn't noted until the gate dragged at 45 degrees.

Here's what a complete field survey covers.

The rule that saves the most rework

Measure three times and build to the smallest.

Openings are almost never square. On any railing run, measure at the top, middle, and bottom — or left, center, and right — and fabricate to the smallest of the three. Record all three numbers, because the spread between them tells you how much adjustment you need to build in. A run that varies by an eighth of an inch and a run that varies by an inch are two different fabrication problems, and you can't tell them apart from a single measurement.

This takes an extra ninety seconds on site. It prevents the single most common cause of a railing that won't drop into place.

What to capture before you leave

Scope, specifically. Level railing, raked stair railing, wall-mounted handrail, swing gate, slide gate, fence run, window guard — check what applies. "Railing job" is not a scope.

Mounting substrate, verified. This is where money disappears. Concrete slab, footing, brick, stone veneer, wood framing, steel, soil, pavers. Veneer is not structure. Confirm what's actually behind stone or brick before you price surface-mounted posts, because a post anchored to a veneer face is a callback waiting to happen. Pavers over sand need a footing. Note slab or footing thickness, and whether you're core drilling or surface mounting.

Install access. Can a truck reach the work area, or is everything going through a 32-inch side gate? Stairs with no lift? Crane required? Measure the narrowest passage in both width and height, and note the longest single section that will fit through it. That number determines how you break up the fabrication — and it's much better known now than after you've welded a 14-foot run.

Obstructions. Walk the whole run. Downspouts, hose bibs, gas and electric meters, A/C condensers, sprinkler heads, landscape lighting, low-hanging branches, expansion joints, existing anchors. Every one of them is a field modification if you find it on install day instead of survey day.

Buried utilities. Before setting any post in the ground, call 811 for utility locates and allow the required notice period in your lead time. Confirm in writing who's responsible for locates — you or the GC.

Code, and why you write the numbers down

Get the jurisdiction, the code edition in force, and whether the occupancy is residential or commercial. Then get the actual required guard height, handrail height, and maximum opening for this job, and write them on the survey.

Requirements differ between residential and commercial, between code editions, and by local amendment. Pool and barrier codes are a separate standard again. A shop that fabricates from memory — "guards are 42 inches" — will eventually build a run that has to come back out.

Also note whether the job needs a permit, stamped drawings, submittal to the GC or architect, HOA or historic review, wind load calculations, or ADA handrail extensions. Each of those has a lead time attached, and each one is a reason a job stalls after you've already bought material.

Gates: the measurement most often missed

Ground clearance across the entire swing arc. Not just at the closed position.

Measure from the bottom of the gate to grade at 0 degrees, 45 degrees, and 90 degrees of swing, and note which direction the ground falls. A gate that clears when shut will drag at 45 degrees if the drive slopes — and that's a return trip, not a warranty claim.

Beyond clearance, capture the clear opening required, existing post-to-post if posts are already set, gate height, single or double, estimated leaf weight, swing direction, and hinge side. For posts and hardware: post size and material, footing depth and diameter, hinge type and quantity, latch or lock type, and whether existing posts are reusable.

If the gate is automated, the scope widens considerably. Note whether power is available at the gate, conduit run distance, the operator type, and which accessories are in scope — keypad, card reader, safety loops, edge sensors, photo eyes, intercom, exit loop, emergency access. Then write down who supplies the operator and who does the electrical, because that ambiguity has swallowed a lot of margin.

Powered vehicular gates in the US are governed by UL 325 and ASTM F2200. Entrapment protection, gate class, and construction requirements aren't optional. Confirm current requirements with your operator supplier and record who carries compliance responsibility on this job.

Stairs: measure the first and last riser separately

Risers are rarely all equal, and the bottom step is usually the odd one out once finish flooring goes in. Ask what floor covering is still to be installed at the top and bottom, and record it.

Capture the number of risers, rise per step, tread depth, nosing projection, stair width, total rise floor to floor, total run nosing to nosing, and handrail height above nosing. Note landings, winders, curved sections, rake-to-level transitions, and whether a volute or turnout is wanted at the bottom.

For wall-mounted handrail: bracket type and spacing, clearance to wall, whether wall backing is present, and whether extensions are required at top and bottom.

Photograph everything

Photos cost nothing and settle arguments that words won't. Take a wide shot of the full run or opening, a close-up of every mounting point, each end condition, the substrate and any existing anchors, every obstruction you noted, the ground across the gate swing, any existing work you're matching, and the access route for install.

Put a tape measure in at least one shot for scale.

Site conditions get covered up, fixed, and forgotten. A dated photo from survey day is the only version of the site that stays true.

Get initials on the dimensions

Before you leave, have the customer or site contact initial the recorded dimensions. It takes ten seconds and it converts your measurement from your claim into a shared record. On the day someone says the opening was different, you have a document.

Write down other notes too — verbal agreements, things the customer asked for in passing. Those are the items that resurface later as "but you said."

Get the printable checklist

We've put this entire survey into a free four-page checklist you can print and keep in the truck. It covers job information, scope, site conditions, code and approvals, railing runs, stairs, gates, finish, a photo list, and a field sketch grid with a sign-off block.

Download the Jobsite Measurement Checklist →

From field numbers to shop drawings

A survey is only worth the time it took if it becomes a drawing quickly. Numbers that sit in a truck for four days go stale, and a job that takes a week to quote is a job someone else has already quoted.

The drawing is also what turns your measurements into an agreement. A dimensioned elevation at the customer's actual opening, showing spacing, heights, post positions and finish, is something they can sign — and a signed drawing is a far stronger record than a line of text on a quote. If the job changes later, you have a precise baseline to price the change against instead of an argument about what was discussed on site.

FabCAD is built for exactly that handoff. Enter the dimensions you captured, select your materials and style, and it draws the gate, railing or fence and generates the complete bill of materials at the same time. Field survey in, shop drawing and cut list out — in minutes rather than hours, which is what makes it realistic to do on every job instead of only the big ones.

See how FabCAD works →