As soon as concrete gains enough strength to eliminate immediate distress or deflection under loads resulting from its own weight
and some additional loads, formwork should be stripped to allow other construction activities to start. The operation of removing the forms is called stripping or wrecking the forms. Formwork can either be partially stripped by removing small areas to prevent the slab from deflecting or completely stripped to allow the slab to deflect. As a general rule, formwork supporting members should not be removed before the strength of concrete has reached at least 70 percent of its design value.