In construction, formwork (or shuttering) is a temporary mold used to hold wet concrete in place until it cures. The choice of material depends on cost, reusability, structural requirements, and the desired surface finish.

The most common materials for formwork are:

1. Timber / Plywood

This is the most traditional and widely used formwork material.

• Plywood: Specifically, Phenolic Birch Plywood (film-faced plywood) is preferred because it is smooth, durable, and water-resistant, leaving a clean finish on the concrete.

• Lumber: Used for framing (joists, studs, and shores) to support the plywood sheathing.

• Pros: Easy to cut and assemble on-site; flexible for complex shapes; low initial cost.

• Cons: Limited lifespan (absorbs water, warps); labor-intensive to construct.

2. Steel

Steel formwork consists of prefabricated panels with a steel frame.

• Pros: Extremely strong and durable; provides a very smooth, precise finish (often requiring no plastering); high reusability (100+ uses); fast to assemble.

• Cons: High initial cost; heavy (requires cranes); limited to standard shapes (not easily customized on-site); prone to rust if not maintained.

3. Aluminum

Lighter than steel, aluminum formwork is popular for large-scale repetitive projects, particularly for mass housing (known as MIVAN formwork).

• Pros: Lightweight (reduces crane dependency); high reuse rate; quick erection; produces high-quality monolithic structures (walls and slabs cast together).

• Cons: Higher initial investment than timber; less strength than steel; flexibility under high pressure requires careful bracing.

4. Plastic / Fiberglass (FRP)

Fiberglass Reinforced Plastic (FRP) formwork is used for specialized applications.

• Pros: Lightweight; non-corrosive; creates extremely smooth surfaces; ideal for complex geometries, curved surfaces, or architectural textures.

• Cons: High cost per unit; low reusability compared to metal if used for simple repetitive shapes; relatively low rigidity.

5. Fabric Formwork

This involves using geotextile fabrics stretched over frames.

• Pros: Allows for unique, organic shapes; excellent for erosion control or architectural feature walls; eliminates sharp corners.

• Cons: Limited to specific applications (usually foundations, marine structures, or architectural cladding); not suitable for high-precision structural elements.

Summary Table