A scaffold is temporary structure that people trust with their lives, and it changes as work goes on, as weather hits it and as trades move parts around. That is why it needs inspecting by a competent person before it is first used, before each shift and after anything that could affect it. This checklist walks through what to look at, from the ground up.
Rules and standards
Provincial occupational health and safety rules set requirements for scaffold design, erection, inspection and use. These include the Alberta OHS Code and the regulations in BC and Ontario, and they differ in detail, for example on when engineering design is required, how often inspections must happen and whether tags are mandatory. CSA Z797, the code of practice for access scaffolding, is widely used as good practice and is referenced in some provincial rules. Follow the manufacturer's instructions for system scaffolds. Check the requirements in your province before work starts.
Scaffolds above certain heights, with unusual configurations or with heavy loads, typically need to be designed by an engineer. Erection, alteration and dismantling must be done by competent workers under supervision.
When to inspect
- After erection and before first use
- Before each shift, or at the interval your province requires
- After any alteration, partial dismantling or addition
- After high winds, heavy rain, snow, ice or a thaw
- After any impact, such as from equipment or a vehicle
- When it has been unused for a period
Scaffold tags
Many sites use a tag system at each access point. A common convention is green for safe to use, yellow for use with specific precautions such as fall protection, and red for do not use. The tag shows who inspected the scaffold, when and any restrictions. Whatever system your site uses, everyone must understand it, and no one should use a scaffold without a current tag.
Footings and base
- Ground firm and level enough, with no soft spots, washouts, frozen ground thawing or excavations nearby
- Mudsills or sole plates of adequate size under every leg on soil or other soft surfaces
- Base plates or screw jacks under every leg, in full contact
- Screw jacks within their maximum extension
- No bricks, blocks, boxes or other makeshift packing under legs
- Castors on mobile scaffolds locked when in use
Frames, tubes and bracing
- Scaffold plumb and level
- All frames, standards, ledgers and transoms in place and undamaged
- Cross braces and diagonal bracing complete and secured
- Couplers, pins and locking devices in place and tight
- No bent, cracked, corroded or mismatched components
- Components from different manufacturers not mixed unless approved
Ties and stability
- Ties to the structure at the spacing required by the design or manufacturer
- Ties not removed by other trades for access or cladding work
- Outriggers or stabilizers in place where required
- Height-to-base ratio within limits for freestanding and mobile scaffolds
- Extra ties where sheeting or netting increases wind load
Working platforms
- Platforms fully decked across the width needed for the work, with no large gaps
- Planks or decks rated for scaffold use, in good condition and secured against movement and uplift
- Correct overlap or support at plank ends
- Platforms free of ice, snow, mud, debris and trip hazards
- Loads within the rated capacity, with materials stacked evenly and not concentrated
Guardrails and edge protection
- Top rails and mid rails on all open sides and ends at the required height
- Toe boards in place to stop tools and materials falling
- Gap to the building face within limits, or guarded
- Guardrails not removed for loading without other fall protection in place
- Netting or screens where people work or walk below
Access
- Safe access to each platform by built-in ladder, stair tower or secured ladder
- No climbing on cross braces or frames unless designed as a ladder
- Access gates or openings protected
Surroundings
- Safe clearance from overhead power lines, as required by your province
- Protection against vehicle and equipment impact
- Area below barricaded where there is a falling object hazard
- Adequate lighting for work and access
Do not use it if in doubt. If any item fails, tag the scaffold out of service and have a competent person correct it before anyone goes back on. Workers should never alter a scaffold themselves to suit their task.
Recording the inspection
The tag at the access point tells workers the scaffold's status today. The written record shows the history. Whatever form your site uses, each inspection should record:
- The scaffold's identification and location
- Date and time of the inspection, and the competent person's name
- The reason for the inspection: first use, pre-shift, after weather, after alteration
- Defects found and what was done about them
- Status after inspection, matching the tag: safe to use, use with restrictions, or do not use
- Any restrictions, such as a reduced load or a fall protection requirement
A typical case
On a mid-rise building, a frame scaffold is erected and tied for a masonry repair. Weeks later, a cladding crew starts on the same elevation and removes several ties that are in the way of their panels, planning to put them back at the end of the day. That afternoon the wind picks up. The scaffold is now taller than it is stable for without those ties, and the top lifts begin to sway.
The site superintendent clears the scaffold, has the scaffold crew reinstall ties at alternative locations agreed with the designer, and has a competent person reinspect it before work resumes. The real fix was procedural: any change to ties now goes through the scaffold supervisor, cladding work is sequenced with the scaffold crew, and the pre-shift inspection specifically confirms tie count against the design. Most scaffold failures come from changes made after the scaffold was erected correctly.
Common mistakes
- Inspecting from the ground only. Platforms, ties and guardrails on upper lifts need a close look, not a glance from below.
- Leaving a green tag after a change. Any alteration, impact or severe weather means reinspection before the tag stays green.
- Overloading platforms with materials. Pallets of block or stone stacked on a light-duty platform can exceed its rating.
- Climbing frames instead of using the access. Cross braces are not ladders.
- Mixing components. Parts from different systems may look compatible but are not rated together.
Fall protection on scaffolds
A properly guarded platform usually provides fall protection without harnesses. During erection and dismantling, or where guardrails cannot be installed, workers need a fall protection system and anchors suited to the scaffold. See the fall protection hierarchy and anchor points for fall protection.
How ehZee can help
Our ladder and scaffolding inspections give owners and contractors an independent check of scaffold condition, tagging and inspection records. We report problems found and what to fix first. For ladders, see a ladder inspection checklist.
Common questions
Who can inspect a scaffold?
A competent person: someone with the knowledge, training and experience to recognize hazards in that type of scaffold, as defined by your province's rules. Many sites assign this to a trained scaffold supervisor.
Can other trades remove a tie or plank to get their work done?
Not on their own. Any change must be made by competent scaffold workers, and the scaffold must be reinspected and retagged before use.
Does a mobile scaffold need the same inspection?
Yes, plus checks specific to mobile units: castors and brakes, the height-to-base ratio, outriggers where required and a firm, level surface. Nobody should ride a mobile scaffold while it is being moved unless the manufacturer and your province's rules allow it.