Manual handling in teams during the fabrication of roof trusses

SIM 03/2009/01


There is a high risk of musculoskeletal disorder associated with manual handling of heavy roof trusses in teams during their manufacture. This guidance describes the key risk factors and recommendations for controlling the risks. It also provides actions for inspectors to take during site visits.


This guidance is based on recommendations made by Health and Safety Laboratory (HSL) ergonomists to support a successful prosecution following a workers serious injury after being struck by a heavy roof truss.  

Provision of mechanical handling equipment to reduce the risk of manual handling injury during handling of roof trusses has also been shown to be reasonably practicable. An appeal against an Improvement Notice to provide mechanical handling equipment, where heavy trusses were being made, was unsuccessful.

Be aware of key risk factors

The risks of musculoskeletal disorder associated with the team manual handling of heavy roof trusses during truss fabrication, are mainly associated with direct handling of loads that are outside of individual capability and with the potential for a breakdown in control or coordination of the task. The risks are present throughout all phases of the truss handling operation (eg the initial lift from the jig/bed, the carry to the stack and peak-up stacking).

The conditions in many roof truss fabrication plants are often not suited to team handling tasks. The environments (eg high noise levels, high light levels, cluttered wood stock piles, the need to jump down from work beds and large distances between team members) makes it very difficult to coordinate the handling operation.

The difficulty in team member communication combined with the heavy, flexible load and the cluttered workspace means there is a high risk of incidents occurring. For example, operatives may lose their grip on the truss, slip or trip on an obstacle en-route, and make rapid/sudden movements to maintain their balance, or to avoid injury while attempting to recover after slipping (using awkward postures and/or induced large forces at the joints). They may also bear a disproportionate amount of the load. Occurrences such as these could result in musculoskeletal injury to one or more members of the team.

Control the risk

Measures should be introduced to reduce the risks of musculoskeletal injury associated with the team manual handling of roof trusses using the following HSL recommendations:

Under circumstances incorporating the improvements set out above, teams of operatives could handle the following loads:

These relate to jig and bed fabrication methods identical or similar to those described on the Roof truss manufacture webpages (new link required to webpages once live).

Trusses that weigh over 95 kg should not be handled by manual means alone. Some form of mechanisation or mechanical assistance should also be used, see Roof truss manufacture for details.

Teams of five persons or more should be avoided; the extra team members do not contribute much more and may make the team difficult to coordinate properly.

The use of four person teams must relate to the size of truss to be handled, operatives must have good access to the load, at a convenient lifting position. The use of a four-person team may not be suitable for smaller trusses.

Peak-up stacking can be carried out up to a maximum truss weight of 95kg. The number of people involved should follow the relationship of team members to load set out above. Each team member should have clear and unhindered access to the load.

Actions for inspectors during site visits

This information is in addition to the guidance within the Manual handling risk assessment flow charts (MAC) where local factors may make the work higher or lower risk, eg heavily restricted posture, contaminated floor.


This guidance is based on the Enforcement Management Model (EMM) Version 3.1

Immediacy of risk - Failure to provide mechanical handling equipment, or having team numbers smaller than the HSL recommendations, should not normally be considered an immediate risk of a serious personal injury.

The benchmark is compliance with the Manual Handling Operations Regulations and the additional information given in this SIM. Use the single casualty's tables. Where roof trusses greater that 95 kg are being handled the benchmark is: Serious Health Effect - nil/neg

The following are relevant when deriving the authority of standards. Which standard(s) is/are relevant when applying the EMM depends on the change in behaviour or activity you are seeking to achieve, ie whether the change you want is documented in a defined, established or an interpretative standard.

Title Authority
Manual Handling Operations Regulations 1992 (as amended) Defined
SIM - Manual handling in teams when manufacturing roof trusses Interpretive


Manufacturing, Transportation and Utilities Sector (General Manufacturing Section)
Updated 2022-08-16