Properly constructed formwork determines the shape and dimensions of a concrete element, as well as the safety of the construction process. Even robust formwork can deform if it is not adequately braced during concrete pouring. Want to reduce the risk of costly repairs and ensure that work is carried out in accordance with good construction practice? It is worth learning how to secure formwork against concrete blowout – from the start of pouring right through to formwork removal.

Table of contents:

1. Where should you start when preparing formwork?
2. How do you reinforce formwork before pouring concrete?
3. Checks before concrete pouring begins
4. The condition of components affects the work process
5. Precision reduces the risk of problems
6. How can you reduce the risk of errors when erecting formwork?
7. Regular equipment inspections help prevent costly repairs
8. Well-prepared formwork is the result of several complementary measures
9. FAQ

Where should you start when preparing formwork?

Effective protection of formwork against concrete blowout must be planned before pouring begins. Simply positioning the components is not enough, as the entire structure must be checked for correct connections, stability and compliance with the design documentation. On every construction site, it is important to follow the manufacturer's recommendations and applicable guidelines, as different systems use different assembly solutions.

Choosing the right formwork components is also essential. They should be complete, free from deformation and properly matched to the planned structure. Before work begins, the condition of the supporting ground must also be assessed, because even a correctly assembled formwork system will not remain stable if it is installed on an uneven or settling surface.

How do you reinforce formwork before pouring concrete?

This question arises when constructing both simple foundations and more complex reinforced concrete elements. The first step is to check all connections and identify the areas subject to the greatest loads. Formwork ties play an important role because they maintain the correct spacing between opposing panels.

Formwork props (push-pull props) are equally important, as they stabilise the position of the entire system. Formwork operations also involve various other accessories that securely connect individual components. Depending on the system used, these may include:

• pins,
• wedge clamps and the appropriate key for operating them,
• wedges,
• clip connectors,
• edge hooks,
• tensioners,
• waler clamps,
• formwork clamps.

Each of these components helps prevent connections from spreading apart and keeps the formwork correctly aligned.

It is worth remembering that walers and beams distribute loads over a larger area, so correct installation is important for maintaining the stability of the entire system. When using self-compacting concrete, the formwork design should account for the pouring method and the arrangement of props and formwork ties. The design and installation should be based on structural calculations.

Checks before concrete pouring begins

Immediately before pouring begins, all connections should be checked again to ensure that the pressure exerted by the concrete will not cause any components to move. Particular attention should be paid to corners, panel joints and the points where walers are secured. These are the areas most susceptible to formwork spreading under pressure if assembly errors or loose connections have been left uncorrected.

Positioning the formwork does not complete the preparation process. Before moving on to the next stage, check that all connections are rigid and that the formwork accessories have been installed correctly. Even small amounts of play can lead to movement that may take considerable time to rectify. For this reason, every inspection before work begins helps reduce the risk of unplanned downtime.

It is also worth checking that the formwork arrangement complies with the design and the specified construction method. Formwork should not be treated as a universal solution suitable for every project. If the concrete mix or pouring method changes, the design should be reviewed again. This approach helps minimise the risk of errors during the preparation stage.

During the inspection, check the following:

• the condition of all connections – no visible looseness and secure fastening of components;
• the arrangement of props and ties – compliance with the design and system instructions;
• the fastening of walers, beams and other components – with no signs of deformation;
• the completeness of the equipment – all required components must be in place.

The condition of components affects the work process

Regular maintenance of the equipment is also important. Before each reuse, components showing signs of excessive wear or visible damage should be replaced. This applies to both panels and the components used to connect them. Leaving damaged parts in place increases the risk of problems during concrete pouring and may make subsequent striking more difficult.

Stored equipment should be protected against moisture, dirt and weather conditions. Prolonged exposure to rain, snow or accumulated dust means that some components may need thorough cleaning before they can be used again. Dust can also make it harder to assess the condition of surfaces and connections, so all contaminants should be removed before assembly.

If plywood panels are used, make sure their surfaces are free from delamination and cracks. High-quality formwork plywood is used where adequate rigidity and consistent dimensions of the formwork elements are required. However, even the best facing material will not prevent leaks at construction joints or around formwork tie holes. In these critical areas, the key is professional concrete sealing using specialist bentonite tapes, sealing profiles, plugs and waterproof adhesives.

Precision reduces the risk of problems

During construction work, it is important to follow the established sequence of operations and avoid skipping inspections at individual stages. Careful formwork installation affects the strength of the elements being constructed and improves the safety of everyone on site. This applies to foundations, walls, columns and slabs, where system stability is particularly important. Many problems result from rushing or using components that have not been inspected beforehand. If you have any doubts about a particular system, always consult the manufacturer's documentation (for example, the DTR – Technical and Operating Documentation) rather than applying solutions from other systems. This approach helps prevent errors that could delay the project.

How can you reduce the risk of errors when erecting formwork?

Careful preparation at every stage of the work helps reduce the number of problems that arise during concrete pouring. Before the concrete mix is poured, check once again that all equipment is present and that each component has been secured correctly. Minor shortcomings left unaddressed at this stage often become apparent only during the work itself, when correcting them requires operations to stop. Before proceeding, make sure all connections are stable and that the formwork accessories have been installed in accordance with the instructions.

Regular equipment inspections help prevent costly repairs

The technical condition of components should be assessed before every assembly. If cracks, deformation or excessive wear are visible, the affected parts must be replaced before work begins. This applies to both panels and the smaller components that hold the entire system together. Leaving damaged parts in place increases the risk of problems during concrete pouring and may make subsequent striking more difficult.

Proper equipment storage is equally important. Components left exposed to the weather for extended periods wear out much faster. Before storage, remove dust, mortar residue and other contaminants, then protect the components against moisture. In winter, pay attention to accumulated snow, which makes it harder to assess the technical condition of the equipment and can accelerate the deterioration of certain materials.

Well-prepared formwork is the result of several complementary measures

Properly securing formwork does not depend on a single solution, but on carrying out every preparation stage carefully. The right choice of system components, correct assembly and inspection before concrete pouring all matter. Only by combining these measures can you reduce the risk of formwork movement and avoid unnecessary downtime during construction.

That is why formwork preparation should be treated as an integrated process in which each stage builds on the previous one. The more attention you pay to the details before pouring begins, the easier it is to keep the entire system stable and carry out subsequent work efficiently. This approach helps reduce rework, improves safety and makes it easier to construct the structure in accordance with the design.

FAQ:

1. Does every type of concrete exert the same pressure on formwork?

No. The pressure depends on factors including the consistency of the mix, the rate of pouring and the type of concrete. More fluid mixes can exert greater lateral loads, so the requirements for the specific construction method should be checked before work begins.

2. Can the spacing of formwork ties or props be changed without a design?

No. The spacing of these components is determined by calculations that take the anticipated loads into account. Unauthorised changes can weaken the entire system and increase the risk of deformation or failure during concrete pouring.

3. When should additional formwork reinforcement be used?

Additional reinforcement is used particularly for high walls, unusual structural elements or situations where the anticipated loads exceed standard levels. The extent of the reinforcement should be determined by the technical documentation and calculations.

Sources:

General Directorate for National Roads and Motorways (GDDKiA), Specifications for the Execution and Acceptance of Construction Works M-13.01.00 v05. Structural Concrete in Road Engineering Structures. Model Document, Warsaw, 2025.

Kowacki, M. (2019). Formwork and Shuttering. Nowoczesne Budownictwo Inżynieryjne, (1–2), 48–54.