Plastic Packers Used in Structural Lift-Shaft Steelwork
Plastic packers were found between structural steel components within the lift shaft, where steel finger packers or engineered metal shims should have been used. Unless specifically designed and approved for the application, plastic packers must not be relied upon for permanent structural bearing or load transfer. They may compress, creep or deteriorate over time and can soften or melt during a fire. Their failure could create movement within the connection, reduce bolt preload, disturb the alignment of the lift steelwork and potentially leave the structure loose or unstable. The connection should be reviewed by the structural engineer and replaced with approved steel packers installed to the design requirements.
- NCQLE reference
- NCQLE-2026-00018
- Quality topic
- Defects and corrective action
- Lesson type
- Failure
- Evidence rating
- Experience
- Published
- 1 August 2026
- Last reviewed
- 1 August 2026
Evidence basis: Supported by relevant professional experience. This learning is provided for professional consideration and does not replace project-specific competent advice, statutory duties or contractual requirements.
Context
The issue was identified during inspection of structural steelwork installed within a building’s lift shaft. Plastic packers had been inserted between steel components to take up construction tolerances and maintain alignment at a connection. As the steelwork formed part of the permanent lift-support structure, concerns were raised about whether the packers could safely maintain the required bearing, alignment and connection integrity during normal service and fire exposure. During inspection of the lift-shaft steelwork, plastic packers were observed between structural steel components at a connection point. The plastic packers appeared to have been used to take up the gap and maintain alignment instead of approved steel finger packers or engineered metal shims. This raised concerns about compression, creep, loss of bolt preload and failure of the packers during a fire, potentially allowing the connection to become loose or unstable.
The transferable lesson
Materials used to pack structural steel connections form part of the load-transfer arrangement and must be specified and approved by the structural engineer. Plastic packers must not be substituted for steel finger packers or engineered metal shims unless their structural and fire performance has been specifically designed and evidenced. Even a small, seemingly temporary component can compromise the stability, alignment and fire performance of the wider structure.
Recommended action
Specify the required steel finger packers or engineered metal shims on the structural connection drawings and ensure the correct materials are available before erection begins. Brief steelwork installers that plastic packers are not an acceptable substitution for permanent structural connections unless specifically approved by the structural engineer. Inspect and photograph packers, bearing surfaces, bolt installation and connection alignment before the work is concealed or fire protection is applied. Any plastic packers already installed should be referred to the structural engineer and replaced with approved metal packers where required.
Limitations and application
A visual inspection alone cannot confirm whether the packers are temporary, load-bearing or part of an approved proprietary connection. Requirements depend on the structural design, connection forces, bolt arrangement, tolerances and required fire resistance. The connection must be assessed against the approved drawings and specifications by the structural engineer. Packers must not be removed or replaced without an agreed method, as the connection may already be carrying load and could require temporary support.