Concrete and its reinforcement

3.1.12Formwork

Formwork shall be structurally adequate and constructed in a workmanlike manner

Formwork should be accurately set out in relation to relevant reference lines and benchmarks. Accuracy is essential to ensure that the correct cover to the reinforcement is maintained.

Formwork and its supports should be rigid enough to maintain the correct position and to withstand extra loads and accidental knocks likely to occur during placement and compacting. Wedges, inserts and boxes should be firmly secured to avoid displacement during vibration.

For concrete which is to be left untreated, or with minimum finishing, formwork joints should be tight to avoid grout loss and
ragged edges. Joints between shutters should be constructed for easy stripping. Any holes for bolts or spacers should be drilled with care to avoid disfiguring or splintering the formwork surface and giving a poor finish.

Formwork should be capable of being struck without damage to the concrete. Formwork should be dismantled without shock, disturbance or damage to the concrete. Support for load-bearing elements should not be removed until the concrete has achieved sufficient strength, as detailed by the designer. Props under suspended floors or beams should be released from the centre, outwards, to avoid overloading.