Architectural drawings show the design intent, but walls are never exactly where the drawings put them. Studs bow, corners are out of square, floors slope and columns get furred out wider than planned. Custom millwork is built to fit, so the dimensions that matter are the ones on site. Field measuring is how those dimensions get into the shop drawings before production, and timing it right is one of the simplest ways to avoid pieces that do not fit.
Shop drawings start from the architect’s drawings. Where a dimension depends on the building, such as a wall-to-wall run, a niche, a bulkhead height or the space around a column, the shop drawings mark it as a field dimension to be confirmed. Production of those pieces should wait until the dimension has been measured on site, or until the GC confirms it in writing. Our article on millwork shop drawings explains how these are shown.
The best time to measure is once the surfaces the millwork will meet are in their final position:
Dimensions change between bare studs and finished, taped drywall, so final measurements are best taken once boarding is done in the millwork areas, and after taping where finish build-up affects the dimensions. Measuring at framing should be reserved for long-lead items, and then only against written hold dimensions from the GC, who takes responsibility for the site matching them. Measuring too late pushes production into the critical path, so the usual compromise is to measure as soon as drywall is finished in the millwork areas and to release less dimension-sensitive pieces (such as freestanding cabinets) for production earlier.
Millwork is detailed so it can absorb some site variation without remaking pieces:
These details have limits. Scribes and fillers are sized for normal out-of-square and out-of-plumb conditions, not for a wall built in the wrong place. Large differences need to be found by measuring, not by the installer on the day.
Freestanding store fixtures rarely need field measuring, but wall units, cash wraps that fit between columns, and built-in feature walls do. On a multi-store program, store layouts vary even when the design is standard, so plan how each store’s critical dimensions will be confirmed, whether by a site visit, the GC’s measurements or a survey. Getting this into each store’s readiness check avoids surprises at installation. See our store fixture installation checklist.
Responsibility for field dimensions varies by contract: sometimes the millwork manufacturer measures, sometimes the GC provides confirmed dimensions, and sometimes the installer does. Make it explicit in the contract and the schedule who measures, when, and who is responsible if dimensions change after they are confirmed. Changes after measuring are a common source of extra cost and delay.
Our drafting team issues shop drawings for review, and items can be approved and released for production line by line, so pieces that do not depend on site dimensions can move ahead while others wait for confirmed measurements. How field dimensions are obtained is agreed for each project. Send us your drawings and schedule and we will flag which items depend on site measurements.
Walls, floors and ceilings are rarely exactly where the drawings show them. Custom millwork is built to fit, so dimensions that depend on the building are measured on site and confirmed on the shop drawings before production.
Once the surfaces the millwork meets are in their final position, usually after drywall is up in the millwork areas, with floors, bulkheads and frames in place. Less dimension-sensitive pieces can be released for production earlier.
An oversize edge on a panel or cabinet that the installer trims on site to follow an uneven wall or floor. Scribes absorb normal site variation, not large errors such as a wall in the wrong place.
The woodwork standards expect casework to be installed level, with toe base shimming up to about 12 mm (1/2 in) acceptable. Floor variations greater than that should be corrected before the cabinets are installed.
It depends on the contract. The millwork manufacturer, the GC or the installer may measure. The contract and schedule should say who measures, when, and who pays if dimensions change after they are confirmed.
