Ladder-Jack Scaffolds

A ladder-jack scaffold is a platform (planks) supported by brackets (ladder jacks) hooked on two ladders. It's a cheap, quick way to work along a wall, but it's one of the less stable scaffold types. Falls happen when ladders slip, planks move, or workers overload or step off the end. In many cases a safer scaffold or lift is a better choice.

• Painters
• Drywall & Plaster Crews
• Siding Installers
• Maintenance Workers

What OSHA requires

Ladder-jack scaffolds are covered by 29 CFR 1926.452(j) and the general scaffold rules (1926.451). Key points include:

• Maximum height: the platform height must not exceed 20 feet.
• Ladders: must meet the OSHA ladder requirements (Subpart X), and job-made ladders must not be used to support ladder jacks. Manufacturers generally call for heavy-duty (Type I or higher) ladders for this use. See Job-Made Ladders.
• Jack bearing: ladder jacks must be designed and built to bear on the side rails as well as the rungs, or, if bearing on rungs only, the bearing area must be at least 10 inches long on each rung.
• Securing the ladders: ladders must be placed, fastened and equipped with devices to prevent slipping.
• Platforms: scaffold platforms must not be bridged one to another, and must be scaffold-grade planks or platforms, set and secured as the rules require. See Scaffold Planks & Decking.
• Fall protection: workers on ladder-jack scaffolds must be protected from falls; OSHA calls for a personal fall arrest system for this type (a guardrail system usually isn't practical). Tie off to a secure anchor that is not the scaffold or ladder. See Personal Fall Arrest Systems.
• A competent person must supervise the setup and inspect the scaffold. See Scaffold Tags.
• The scaffold must support its own weight and at least four times its maximum intended load, and loads must be within the ladders' and jacks' ratings.

Many contractors and manufacturers require that you only use ladder jacks for light-duty work, with limited loads, and the manufacturer's instructions take priority. If rules differ by your location or site, follow the stricter.

Setting up the ladders and jacks

• Use two heavy-duty (Type I or higher), matching ladders in good condition, with sound rungs and rails. Don't mix ladder types. Ladders must be of the same height and set at the right angle (about 4 to 1), on firm, level ground.
• Secure each ladder top and bottom so it can't move: tie off at the top to a stable structure, and fit non-slip feet and bottom restraints or have another worker footing it where allowed. Don't use ladders on soft ground or ice. See Extension Ladders.
• Set the jacks at the same height on both ladders and check they sit on the rungs fully with the hooks engaged and locked, with bearing on the rails or 10 inches on the rungs.
• Place scaffold-grade planks of the right size on the jacks, overlapping at least 12 inches where they meet and extending no more than 12 inches past the supports unless restrained. Secure planks so they can't slide, lift or kick up. Don't use a single plank that's too long or too weak for the span.
• Keep the span short and within the load limit of the planks and ladder, since ladder jack scaffolds are designed for light loads and a few people at most.
• Check the ladders and jacks for damage and don't use them if jacks are bent, cracked or worn. See Fall Gear Inspection.

Working from the platform

• Climb the ladder facing it, with both hands free, and put your tools up by hoist or tool belt. Don't climb with loaded hands.
• Tie off your harness to an approved anchor before stepping onto the platform.
• Stay between the ladders, keep your weight centered, and don't overreach or step on the overhang. Don't jump or bounce on the planks.
• Don't move the scaffold with workers or loads on it. Don't use it near power lines or in wind. See Scaffold Weather.
• Keep the platform free of clutter, and tools and materials within the load limit. Don't stack buckets or planks.
• Don't use ladder-jack scaffolds for heavy materials, hot work or for more than the number of workers the design allows.

Safer alternatives

• Mobile scaffolds or small rolling platforms are more stable and allow guardrails. See Mobile Scaffolds and Platform Ladders.
• Scissor lifts and other aerial lifts give a safer platform for long work. See Scissor Lifts and Aerial Lifts.
• Frame or system scaffolds for bigger jobs. See Frame Scaffolds.
• Ask: is there a way to do the work with less risk, such as using extension poles, pre-assembly or lifts?

Ladder-jack scaffold checklist

• The platform is no more than 20 feet high and used only for light work
• The ladders are heavy-duty (Type I or higher), not job-made, secured at the top and bottom
• Jacks bear on the rails or 10 inches on the rungs and are at the same height
• Planks are scaffold-grade, secured, not bridged and within load limits
• I'm tied off to a separate anchor and a competent person inspected the setup

Last updated: October 5, 2026