Formwork and Falsework

Formwork is the temporary mould into which concrete is poured; falsework is the temporary structure supporting the formwork.
Falsework collapse during concrete pours is one of the most catastrophic failures that occurs on construction sites.
BS 5975 requires all formwork and falsework to be designed by a competent person and independently checked before use.
A permit to load must be issued by the temporary works coordinator before any concrete is placed into the formwork.
Falsework must be erected exactly as designed — changes to prop positions, bracing, or base conditions invalidate the design.
Foundations for falsework props must be on firm ground with sole plates to spread the load and prevent settlement.
Formwork must be oiled or treated with release agent before reinforcement is fixed to allow clean stripping later.
Striking of formwork must only occur when concrete has reached the required strength, confirmed by cube test results.
Inspection of formwork and falsework must take place before, during, and after the concrete pour to detect movement.
Backpropping of lower floors must be maintained when formwork is loaded on upper floors to prevent overloading.

Prevent catastrophic collapse	Falsework failure during a concrete pour collapses the entire structure instantly — proper design and inspection are mandatory.
Permit to load	Concrete must not be placed until the temporary works coordinator has inspected and issued a permit — this is the critical control.
Striking too early	Removing formwork before concrete has reached the required strength causes structural collapse — cube test results must confirm readiness.

Do

Don't

Ensure formwork and falsework have an approved design and independent design check.
Obtain a permit to load from the temporary works coordinator before pouring concrete.
Erect falsework exactly as shown on the design drawings without any deviation.
Place falsework props on firm ground with adequate sole plates beneath base plates.
Apply release agent to formwork faces before fixing reinforcement inside the mould.
Inspect formwork and falsework before, during, and after every concrete pour.
Maintain backpropping on lower floors as specified in the propping schedule.
Confirm concrete cube test results meet the required strength before striking formwork.
Report any signs of movement, deflection, or leakage during the pour immediately.
Follow the agreed striking sequence — never remove formwork out of the planned order.

DON'T use formwork or falsework that has not been designed and independently checked.
DON'T pour concrete without a valid permit to load signed by the TW coordinator.
DON'T alter prop positions, bracing, or any element of the falsework design on site.
DON'T set props on soft ground without sole plates — settlement causes collapse.
DON'T fix reinforcement into formwork without applying release agent to the faces first.
DON'T skip inspections — undetected movement during a pour leads to catastrophic failure.
DON'T remove backpropping from lower floors unless authorised by the structural engineer.
DON'T strip formwork before cube results confirm the concrete has reached design strength.
DON'T ignore leaking, bulging, or creaking formwork during a pour — stop and investigate.
DON'T strike formwork out of sequence — early removal of supports causes structural failure.

See also: Temporary Works Awareness | Concrete Pour Safety

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