Logistics & Installation · SOP
Door Alignment Shim Selection Guide
This SOP provides a systematic method for choosing the correct shim thickness and material to ensure proper door alignment and jamb installation in field environments, reducing warranty callbacks and operational delays.
Estimated Time
20 min
Difficulty
Intermediate
Regulation
CSA A440S1
Version
1.0
Purpose
To standardize the process of selecting and installing shims for door alignment, eliminating guesswork and ensuring consistent gap tolerances across multiple installations. Proper shim selection prevents binding, air leaks, and premature hardware wear.
Scope
This guide applies to all site-installed hinged doors (wood, metal, or composite) in commercial and light industrial logistics facilities. It covers hinge-side and strike-side shimming only. Framing adjustments and warped slabs are outside scope; refer to separate SOPs.
Safety Precautions
- Lockout/Tagout any powered door actuators or closers before shimming. Ensure door is stable and cannot swing unexpectedly.
- Wear ANSI Z87.1 rated safety glasses and cut-resistant gloves when handling shim stock and cutting tools.
- Use a stable ladder or platform when working on doors over 8 ft tall. Never over-reach; reposition ladder instead.
Required Tools & Materials
- Assorted shim stock (plastic, aluminium, or coated steel) in 0.5 mm, 1 mm, 1.5 mm, 2 mm thicknesses
- Feeler gauge set (metric and imperial, 0.05–5 mm)
- Digital caliper (0.01 mm resolution)
- Door alignment laser level (self-leveling)
- Cordless drill with adjustable clutch (3–5 Nm torque range)
- Shim hammer (nylon face, dead blow)
- 6-inch combination square
- Marking pencil, tape measure, utility knife for cutting shims
Procedure: Step-by-Step
1
Inspect door and frame condition — visually check the door slab, hinges, and jamb for warpage, damage, or debris. Confirm door swing direction and frame squareness using a combination square. Record any defects on the site report.
2
Measure gap at hinge and strike sides — use a feeler gauge to measure the gap between the door edge and jamb at three points: top hinge, middle of door, bottom hinge. Record each measurement in mm. Repeat for the strike side.
3
Determine target gap and shim requirement — consult manufacturer specification for acceptable gap (typically 2–4 mm). Subtract measured gap from target to calculate required shim thickness. Use digital caliper to confirm thickness of available shims.
4
Select shim material and cut to size — for exterior doors, use corrosion-resistant plastic or stainless steel shims. For interior, coated steel or aluminium. Mark and cut shim to match hinge mortise width plus 5 mm overhang for easy insertion.
5
Install shim and re-check alignment — insert shim between hinge leaf and jamb (or behind strike plate). Drive hinge screws with clutch set to 3–5 Nm to avoid stripping. Re-measure gaps using laser level. If gap exceeds ±0.5 mm tolerance, add or remove shim layers as needed.
6
Document final measurements — note final gap readings and shim pack composition on the installation checklist. Photo-document the aligned door for quality records. Proceed to next door or close-out.