How & When To Remove Formwork - .au

If you're pouring concrete for a driveway, wall or other home improvement project, formwork is usually needed to hold the concrete in place before it sets. Some formwork remains in place permanently, but most formwork is temporary and should be removed once it's no longer needed.

When should formwork be removed is a common question that doesn't have a straightforward answer. Read this guide to find out how long formwork should be used and how to remove formwork (also called striking the formwork) without damaging your concrete.

Find out more: What is formwork?, Crane equipment hire checklist

When should formwork be removed?

Formwork should only be removed when the concrete has hardened to the point that it can support its own load and loads placed upon it, otherwise it could shift or collapse without support.

Many factors can affect concrete formwork removal times, including:

• Grade of concrete/cement – higher grades can cure faster

• Type of cement – rapid-hardening cement will gain strength faster

• Temperature – concrete sets faster in warmer conditions

• Size of form – larger concrete forms gain strength faster

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Concrete formwork striking times

As a rough guide, when using standard cement in normal conditions:

· Walls, columns and other vertical formwork can usually be removed after 24 to 48 hours. If you're using fast-drying cement, this could be as soon as 12 hours.

· For concrete slabs, formwork can usually be removed after 3 days and props after 2 weeks.

· For beam soffits, formwork should remain in place for 7 days and props for 2 to 3 weeks.

Find out more about how to calculate formwork and factors affecting cost of formwork.

How to remove formwork: step by step guide

If you built your own timber formwork or you're using modular steel or aluminium formwork, you should be able to remove the formwork yourself. For more complex jobs, it's recommended that you hire a concreter or formwork specialist.

Here's how to remove formwork from a slab, wall or other standard concrete structure.

Tools needed

• Hammer

• Stake puller

• Pry bar

Step 1: Wait for the concrete to set

Wait the required time for the concrete to harden and gain enough strength to support itself. For vertical forms, this can mean waiting overnight and removing formwork the next day. For horizontal slabs, it can require several days. Removing formwork prematurely could cause the surface to sag.

Step 2: Start from the top

Remove the highest forms first. If formwork is attached to the stakes with nails, use a hammer to remove these. Don't use a hammer or pry bar against the concrete itself, as this could cause damage.

Step 3: Remove the stakes

Use a stake puller to remove the stakes supporting the formwork from the ground. Avoid contact with the concrete surface as much as possible.

Step 4: Remove the sides

Formwork attached around the sides can be tougher to remove and may need a pry bar. Use the minimum force needed to pry the formwork up from the ground and detach it from the concrete. Formwork should be removed on alternating sides to help maintain structural balance.

Step 5: Recycle or dispose of formwork

If formwork is still in good condition, it may be reused for other parts of your project or stored for future projects. If you need to dispose of formwork, do so responsibly.