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In the construction industry, “form” refers to a temporary structure or mold used to shape and support concrete during the pouring and curing process. Forms are typically made from wood, steel, or plastic and are custom-built to the desired size and shape of the concrete element being constructed, such as a wall, column, or beam. Forms are essential for ensuring that the concrete cures properly and maintains the desired dimensions and finish.

Composition and Structure

Forms are typically made from the following materials:

  • Wood: Wood forms are the most common type of form used in construction. They are typically made from plywood, dimensional lumber, or engineered wood products such as laminated veneer lumber (LVL). Wood forms are relatively inexpensive and easy to work with, making them ideal for a wide range of concrete construction projects.
  • Steel: Steel forms are more durable than wood forms and are often used for large or complex concrete elements, such as highway bridges or high-rise buildings. They are typically made from steel plates or structural steel shapes and are custom-built to the desired size and shape of the concrete element.
  • Plastic: Plastic forms are lightweight, reusable, and easy to clean, making them ideal for repetitive or mass-produced concrete elements, such as precast concrete panels or blocks. They are typically made from high-density polyethylene (HDPE) or polypropylene and can be custom-built or purchased as pre-manufactured units.

Functionality

The primary function of forms is to shape and support the concrete during the pouring and curing process. Forms serve several important purposes:

  • Shaping: Forms define the size and shape of the concrete element being constructed, ensuring that it meets the desired dimensions and specifications.
  • Support: Forms support the weight of the wet concrete and prevent it from slumping or flowing out of position before it has cured and hardened.
  • Surface Finish: Forms impart the desired texture or finish to the surface of the concrete , such as smooth, rough, or textured. They can also be used to create decorative patterns or architectural details in the concrete.
  • Alignment: Forms ensure that the concrete element is properly aligned and positioned relative to adjacent elements, such as walls, columns, or beams.

Types of Forms

There are several types of forms commonly used in construction:

  1. Wall Forms: Wall forms are used to construct vertical concrete elements, such as walls or columns. They are typically made from plywood or steel and are supported by vertical or horizontal bracing.
  2. Column Forms: Column forms are used to construct cylindrical concrete elements, such as columns or piers. They are typically made from cardboard, fiber, or steel and are supported by vertical or horizontal bracing.
  3. Beam Forms: Beam forms are used to construct horizontal concrete elements, such as beams or lintels. They are typically made from plywood, steel, or precast concrete and are supported by vertical or horizontal bracing.
  4. Slab Forms: Slab forms are used to construct horizontal concrete elements, such as slabs or decks. They are typically made from plywood, steel, or precast concrete and are supported by horizontal or vertical shoring.

Installation and Removal

The process of installing and removing forms typically involves the following steps:

  1. Preparation: The area where the concrete will be poured is prepared by clearing, leveling, and compacting the soil or subgrade.
  2. Assembly: The forms are assembled on-site and securely braced and supported to prevent movement or shifting during the pouring process.
  3. Pouring: The wet concrete is poured into the forms, filling them to the desired level and ensuring that it is properly consolidated and free from voids or air pockets.
  4. Finishing: The surface of the concrete is finished as desired, using tools such as trowels, floats, or screeds to achieve the desired texture or finish.
  5. Curing: The concrete is allowed to cure and harden over a period of several days, during which time it is protected from excessive moisture loss and temperature extremes.
  6. Stripping: Once the concrete has cured and hardened sufficiently, the forms are removed carefully to avoid damaging the concrete.

Maintenance

Proper maintenance is essential for preserving the integrity and functionality of forms:

  • Forms should be inspected regularly for signs of damage, wear, or deterioration and repaired or replaced as needed.
  • Forms should be cleaned and coated with a release agent before each use to prevent the concrete from sticking to the surface.
  • Forms should be stored properly when not in use to protect them from damage and prolong their useful life.

Conclusion

Forms are essential tools in concrete construction, providing a temporary structure or mold to shape and support the concrete during the pouring and curing process. By properly selecting, installing, and maintaining forms, construction professionals can ensure the quality and integrity of the concrete elements they build, from walls and columns to beams and slabs.

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