— Free tool

Slab prop calculator

Enter the height, thickness and dimensions of the slab. In 6 steps you get the spacing of the secondary beams, primary beams and props, the plan and the materials you need.

  • 6 steps
  • Spacings A · B · C
  • Plan and materials list
Start the calculation ↓ H20 formwork table
— Calculation

Slab formwork in 6 steps

— How to read it

What A, B, C mean

A

Secondary beams

The top layer, under the 2.5 cm decking. 8×8 battens or an H20 beam upright or flat.

B

Primary beams

The bottom layer, on the prop heads. H20 or two 8×8 battens one on top of the other.

C

Props

The spacing of the props under each primary beam. The first goes at most 30 cm from the edge.

— Available

Italian-type slab props

Together with the accessories needed to set them up.

See them in the shop →

    • 4-way heads

      One on each prop. The primary beam sits on it.

    • Support tripods

      They keep the prop upright while setting up and at the perimeter.

    • Screw jacks 75 and 100 cm

      When the prop does not reach the height.

    • Clamps

      For cross bracing with Ø48 tube on tall props.

    — Frequently asked questions

    Before you start

    What is the clear height?

    The distance from the floor to the underside of the slab. The calculator subtracts the decking, secondary beams and primary beams itself and works out how far the prop extends.

    Why does the first prop go at most 30 cm from the edge?

    So that the edge of the slab is not left unsupported. The first prop and the first beam go close to the edge and the rest are spread at equal spacings.

    How much does a slab prop carry?

    It depends on how far it is extended: the less it extends, the more it carries. The calculator takes the capacity from the manufacturer's table at the length it will be extended to.

    I use a slab formwork system. Does it work for me?

    Yes. Choose “Slab formwork system” and enter the spacings from the manufacturer's table. The calculator checks whether the props can carry the load and, if needed, places them closer.

    My slab is L-shaped. What do I do?

    Split it into rectangles and calculate each one.

    Does it replace the formwork design?

    No. It is an indicative calculation, so you know what you need and how many. The formwork design is done by the responsible engineer.

    Want a quote for the props?

    Send us the list from the calculation or give us a call.

    Contact +30 22850 62064