When can the formwork be removed?

Formwork is a temporary preparatory construction form for forming a liquid concrete mixture, in which it hardens and acquires the necessary strength. When can formwork be removed is a question that always worries builders on the construction site. It can be removed when the concrete has hardened, and the elements cast from it can hold without formwork.

What factors influence when formwork can be removed?

Strength of the hardened mixture

The basic criterion by which one can judge that it is time to remove the formwork is the strength of the hardened concrete.

Civil engineers know that horizontal formwork should be removed when the concrete has acquired 70% of its design strength. Then you can remove the formwork posts, beams and panels.

Vertical formwork can be removed when the concrete has acquired 50% of the design strength. 

General rule: vertical formwork can be removed earlier than horizontal formwork, since the floor formwork is subject to greater loads.

Air temperature and humidity

Climate conditions also have a great influence on the hardening of concrete in monolithic construction. Warm weather allows the concrete mixture to harden faster, while in the cold season hardening is slower, and the formwork is removed later

Concrete composition

If special additives for rapid hardening of concrete are added to the mixture, then the formwork can be removed earlier.

Building operating conditions

If after formwork removal it is planned to immediately subject the concrete elements to load (weight of workers, materials, equipment), then the formwork should be removed later so that cracks or deformations do not appear in the building.

How do builders check the strength of concrete?

• Visual inspection for cracks or defects
• Non-destructive hammer blow method with rebound
• Compression testing of concrete samples

To remove the formwork, you need to focus not only on a certain number of days, but also on weather conditions, type of structure, and assessment of concrete strength.

Having correctly assessed these parameters, builders decide that it is time to remove the formwork with minimal risk to the building, while adhering to the construction schedule.

With us, you can buy horizontal formwork directly from the manufacturer's warehouse.

VIRASTAR formwork has a certificate of conformity with DSTU and an official guarantee from the manufacturer.

We suggest reading our blog "What kind of maintenance does formwork require?"