Roof Truss Installation — Safe Work Method Statement
Safe Work Method Statement for lifting, setting, fixing and bracing prefabricated timber roof trusses on residential and light commercial buildings, including crane lifts, fall prevention at the top plate and temporary bracing to AS 4440.
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Roof truss installation is High Risk Construction Work because carpenters work at top plate height and above, with a fall of more than 2 metres both outside the building and into it. The crane lift adds powered mobile plant and possibly overhead powerlines. A SWMS is required before trusses are lifted. For housing, the Managing the Risk of Falls in Housing Construction code sets out what is expected: perimeter edge protection at eave height, and protection against falls inside the building, such as fall protection platforms or decks, or working from a scaffold or EWP.
The biggest risk specific to trusses is progressive collapse. A row of trusses that is not properly braced can domino over and take workers with it, especially in wind. Install temporary bracing as each truss is placed, following the truss manufacturer's bracing layout and AS 4440, and keep it in place until permanent bracing, battens and tie-downs are complete. Never release a truss from the crane until it is fixed at both ends and braced. Do not walk along top chords or stand on webs. Stacking roofing materials on trusses before permanent bracing is complete can overload them, so don't do it.
Crane lifts of trusses need a lift plan. Trusses are long, light and catch the wind, so tag lines, a spreader bar for long or girder trusses and a wind limit are needed. Only a licensed dogger or rigger slings and directs the lift, and nobody stands under the load. Bundles landed on the top plates must be supported and spread over walls, not dumped on a span. Overhead powerlines near the house must be identified before the crane sets up.
No WHS licence is required for carpenters setting trusses, but the crane operator and dogger need high risk work licences. The trusses must be installed in line with the manufacturer's truss layout and AS 4440, and the frame inspection required by your certifier must be completed before roofing goes on.
Customise this template with: the building height and roof form; the truss manufacturer's layout and bracing drawings; the perimeter and internal fall protection system; the crane type, set-up position and lift plan; the dogger's licence details; the overhead powerline check; the wind speed at which lifting and work on trusses stops; and the hold point for the frame inspection.
Personal Protective Equipment
High Risk Construction Work Types
- •Risk of a person falling more than 2 metres
- •Work on or near energised electrical installations or services
- •Work in an area with movement of powered mobile plant
Risk Assessment
1.Pre-start checks and fall protection set-up
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Falls from the top plate to the outside of the building | Catastrophic | Install perimeter scaffold or edge protection at eave height before truss installation starts, with guardrails high enough to work for the roof pitch. Inspect it before use and after any alteration. Do not start if any section is missing or incomplete. | Moderate | Builder / Site Supervisor |
| Falls into the building from top plates and trusses | Catastrophic | Provide internal fall protection before work at top plate height, such as fall protection platforms or decking at top plate level, or work from an EWP or mobile scaffold. Do not walk along top plates without fall protection. Plan the installation so carpenters work from the platform, not from the trusses. | Moderate | Builder / Lead Carpenter |
| Crane or load contact with overhead powerlines | Catastrophic | Identify overhead powerlines and service lines before the crane sets up. Position the crane so the boom and load stay outside the network operator's exclusion zone, with a spotter where the lift works near a line. Contact the network operator if a lift cannot stay clear. | Low | Crane Operator / Site Supervisor |
2.Lifting trusses with a crane
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Truss bundle dropped or swinging into workers | Catastrophic | A licensed dogger slings and directs every lift. Use a spreader bar for long and girder trusses and lift at the points the truss manufacturer specifies. Control loads with tag lines. Nobody under the load or between the load and the frame. Stop lifting when wind exceeds the limit in the lift plan. | Low | Dogger / Crane Operator |
| Wall frames overloaded by landed truss bundles | High | Land bundles over load-bearing walls on the top plates, spread across several walls, never on a single span or a temporary deck not designed for it. Check that wall frames are braced and tied down before landing loads. | Low | Lead Carpenter |
3.Setting and fixing trusses
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Progressive collapse of unbraced trusses | Catastrophic | Set the first truss or gable end and brace it back to the ground or structure before adding more. Fix each truss at both ends with the specified connectors and tie it to the previous truss with temporary bracing as soon as it is placed. Follow the truss manufacturer's temporary bracing layout and AS 4440. Never leave trusses unbraced at the end of a shift. | Low | Lead Carpenter |
| Worker falls from standing on top chords or webs | Catastrophic | Never walk along top chords or stand on webs or bottom chords between supports. Work from the internal platform, scaffold or EWP. Where the roof form needs work above the platform, use a working platform designed for the task. | Moderate | Carpenter |
| Nail gun injuries while fixing at awkward angles | High | Use sequential-trigger nail guns for truss fixing. Never bypass safety devices. Keep the free hand well clear of the nail path. Disconnect air or remove the battery before clearing jams or moving between work areas. | Low | Carpenter |
4.Installing permanent bracing, girders and tie-downs
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Overloading trusses before permanent bracing is complete | High | Do not stack roofing, battens or other materials on trusses until permanent bracing and tie-downs are complete. Load roofing materials only as the roof installer's SWMS and the truss manufacturer allow. | Low | Lead Carpenter / Builder |
| Strain from handling heavy girder trusses and bracing | Moderate | Place girder trusses by crane, not by hand. Two-person handling for long bracing members. Pass materials up rather than carrying them up ladders. | Low | Carpenter |
5.Weather, inspection and handover
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Wind loading on a partially installed roof frame | High | Check the forecast before starting and stop lifting and work on trusses when wind exceeds the limit set in the SWMS. Add extra temporary bracing before leaving a partly installed frame overnight or before a forecast storm. | Low | Lead Carpenter |
| Roofing started on a frame that has not been inspected | Moderate | Complete the frame inspection required by the certifier and fix any defects before roof cladding starts. Leave edge protection in place for the roofing trade. | Low | Builder |
Relevant Codes of Practice
Worker Acknowledgement
By signing below, I confirm that I have read, understood and agree to comply with this Safe Work Method Statement.