Preventing roof collapses in housing
This Alert provides information on managing the risks associated with structurally inadequate temporary roof supports in housing construction.
Builders and truss erectors use temporary roof supports (eg pine studs) when permanent roof support structures (eg columns, posts or walls) for porticos, facades, verandas, garage entrances and other areas have not yet been installed.
Temporarily supporting a house's roof structure during the construction can put the roof at risk of collapse, if the temporary supports used are structurally inadequate for the loads exerted on them.
While temporary supports may be structurally adequate for the bare roof skeleton, it may be insufficient when the roof is exposed to additional loads, such as:
- the weight of roofing materials, including point loads
- roof workers installing roofing
- exposure to lateral wind loads, or
- a combination of the above.
A roof held up by structurally inadequate supports puts all workers onsite, and potentially the public, at risk should the supports fail and the roof collapses.
The builder as the person with management or control of the workplace must ensure, the workplace and the means of entering and leaving it are safe and without risks to health, so far as is reasonably practicable.
Before allowing any work on, under or near a temporary supported roof structure, ensure the temporary supports are:
- of adequate strength, stiffness and stability
- can hold the weight of workers and roof materials, including any point loading
- braced to prevent bending or other lateral forces
- secured both top and bottom to prevent dislodgement.
- protected against impacts and damage
For example when a garage or similar type area with large wall openings is to be roofed prior to the completion of the areas structural elements (eg brickwork, lintels) sufficient braces, props, temporary stud walls or a combination of these should be used to support the roof.
Any work on, under or near a temporary supported roof structure has significant risks and all workers onsite must be provided with site specific induction training which includes information and instruction on the hazards and the controls in place to manage the risk of roof collapse, such as the:
- location of temporary supports and bracing
- process to follow to safely get supports or bracing altered
- identification and reporting of support damage and potential failures.
Monitor the temporary supports, as necessary, to enable work to be done safely.
Pic 1: Inadequately supported roof over garage entrance
Pic 2: Inadequate temporary support for portico could lead to roof collapse, and with no physical fall protection workers are at risk of a fall.
Guidance Note - Stability of buildings during construction
Safety Alert - Preventing structural collapse
This Alert contains information following the WorkSafe'sinquiries into the incident at the date of this report. The information contained in this report does not necessarily reflect the final outcome of WorkSafe's action with respect to this incident. WorkSafe does not warrant the information in this report is complete or up-to-date, and does not accept any liability to any person for the information in this report, or its use.