Propping and backpropping support concrete slabs and beams during construction until they gain sufficient strength to carry their own weight and imposed loads. Premature removal or incorrect installation of props has caused catastrophic floor collapses on multi-storey construction projects. This talk explains the principles of propping and backpropping and the critical rules every operative must follow.
Key Hazards
Floor slab collapse from premature removal of props before concrete gains strength
Progressive collapse through multiple floors from inadequate backpropping below
Props buckling or failing under load due to incorrect type, spacing, or base conditions
Workers struck by falling props or debris during uncontrolled striking operations
Control Measures
Install props at the positions and spacings specified in the temporary works design drawing.
Ensure props bear on firm, level surfaces using base plates or sole boards as specified.
Extend adjustable props to the correct height and lock all adjustment pins and collars securely.
Install backprops on the floors below as specified to transfer loads through the structure.
Never remove or strike props without a written permit to dismantle from the temporary works coordinator.
Check concrete cube test results confirm adequate strength has been achieved before striking.
Inspect props daily for signs of movement, buckling, base settlement, or damaged threads.
Brief the workforce on the propping layout and the areas where floor loading is restricted.
Record all propping installations, inspections, and striking activities on the temporary works register.
Remember
Props must be installed at the exact positions and spacings shown on the temporary works design
Never remove props without a written permit to dismantle from the temporary works coordinator
Concrete cube test results must confirm adequate strength before any props are struck
Backprops on floors below must be installed as the design specifies to transfer construction loads
Inspect props daily for movement, buckling, base settlement, or damaged adjustment threads
Record all propping installations, inspections, and striking in the temporary works register
Applicable Legislation: CDM Regulations 2015 · BS 5975:2019 (Temporary Works) · BS EN 12812 (Falsework) · Health and Safety at Work etc. Act 1974