Danger of freestanding masonry walls

Background

Unstable or inadequately braced masonry walls expose workers and members of the public to a risk of death or serious injury.

Recently a worker died after a brick wall collapsed onto him on a construction site. This is the latest in a series of serious incidents involving masonry walls collapsing on construction sites. Other incidents have also resulted in deaths or serious injuries.

Often these walls have lacked the lateral support provided by permanent wall returns or other sections of the final structure such as wall or floor frames, or roof structures; which had yet to be installed.

Control measures

Ensure freestanding masonry walls are stable and adequately braced at all times to prevent collapse when subjected to lateral forces, such as wind.

Temporary bracing should:

• be used where the height of the wall exceeds 10 times the thickness of the wall
• be provided from a lower height where lightweight masonry is used or the wall is in an area where wind speeds are likely to exceed 30 km/h
• stabilise the entire length of the wall so it does not fall in either direction
• not exceed two metres between individual braces
• include wall support bearers (eg battens or strong-backs) of at least 500mm length
• be retained until the required elements of the final structure are installed and provide adequate lateral support.

Where braces are required, they should be regularly checked by a competent person to ensure they are not removed, modified, or damaged.

If extreme weather is forecast, ensure that work ceases and a suitable large exclusion zone around any incomplete masonry wall is established and maintained.

An incomplete freestanding masonry wall should never be used as shelter during extreme weather, even if the wall has temporary bracing.