The formwork area is calculated based on the surface area of concrete that needs to be covered by formwork. Here's how it's calculated for different elements:

Columns:

For rectangular columns: Perimeter × Height

Perimeter = 2 × (Width + Depth)

Beams:

2 × (Depth × Length) + (Width × Length)

(Bottom and two sides - top is typically open)

Slabs:

Length × Width (only bottom formwork needed)

Walls:

2 × (Length × Height) (both sides)

Footings:

2 × (Length + Width) × Depth (all sides)

Formwork can be made from various materials, each with its own advantages:

Timber Formwork:

• Traditional and versatile
• Easy to work with but less durable
• Good for small projects or complex shapes

Plywood Formwork:

• Smooth surface finish
• Reusable but limited lifespan
• Common for walls and slabs

Steel Formwork:

• Durable and long-lasting
• Good for repetitive use
• Higher initial cost but economical for large projects

Aluminum Formwork:

• Lightweight and strong
• Corrosion resistant
• Popular for modular systems

Plastic Formwork:

• Lightweight and reusable
• Good for simple, repetitive shapes
• Limited load-bearing capacity

Design Considerations:

• Ensure formwork can withstand concrete pressure (especially important for tall walls)
• Account for deflection limits (typically L/270 or L/360)
• Plan for easy stripping without damaging concrete
• Include proper bracing and supports

Construction Tips:

• Check dimensions and alignment before pouring
• Seal joints to prevent leakage
• Apply form release agent for easier stripping
• Inspect formwork before each pour
• Follow manufacturer's recommendations for reusable systems

Safety:

• Ensure all supports are properly secured
• Use guardrails for elevated work
• Don't remove formwork until concrete reaches sufficient strength
• Follow OSHA or local safety regulations