Housing construction - Hazards of unsafe roofing supports

Alert

Housing construction - Hazards of unsafe roofing supports ( )

Document Type: Alert
Keycode: web only
Industry: Construction 
Division Author: Construction & Utilities
Publication Date: 09 June 2005
Date First Published: 25 May 2002
Summary: This alert warns of the dangers of structurally inadequate temporary supports and unsafe framing for roof sections during the construction of houses, and advises on preventative safety measures.

The use of structurally inadequate temporary supports and unsafe framing for roof sections during the construction of houses, is a serious risk to workers.

These roof sections could collapse when used by roof tilers, roof plumbers or other trades as a working platform. There are two areas of concern:

 

Structurally Inadequate Temporary Supports

Slender and unbraced single pine props have been observed as temporarily supporting roof framing on front facades, garage entrances and other areas, until permanent supports are completed at a later stage.

Many of these props are at an angle and bending under the weight (see pictures below), clearly indicating that they are inadequate as supports.

Inadequate, slender supports on garage entrance.

Risk of facade collapse due to inadequate support. Lack of fall protection on roof also puts worker at risk.

Recommendations for temporary supports

Garage entry

Prior to completion of the brickwork in the garage (when the lintels are not in place), braced props or temporary stud walls should be used for supporting the roof framing.

This will not apply to brick-veneer garages; timber lintels are in place in these circumstances.

Front facades

Temporary supports should be:

• engineered for adequate strength, stiffness and stability
• of such material and large enough to hold the weight of workers and stacked tiles
• appropriately braced to resist bending under load
• adequately secured at the top and bottom to prevent dislodgement.

Unsafe Framing

The practice of supporting the fascia at gable ends off short outriggers which are skew nailed or gang nailed to the last rafter (see pictures below), has resulted in failures. Similar risks may also occur where creeper rafters are not properly secured to the hip rafter.

 

Recommendations for fascia supports

Outriggers must be robust and therefore need to be continuous over the gables (see illustration below left). Similarly, all creeper rafters must be fixed to the hip (see illustration below right). Both illustrations are from the Victorian Timber Framing Manual. Any variations should be suitably engineered and comply with design recommendations.