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Acrow Props are an essential tool for formwork shoring worldwide, offering high-strength support for vertical loads. Our step-by-step explains how to use Acrow Props and their common uses in construction.
William de Vigier created the prop in the 1930s as an alternative to the custom-built timber props of the time. Their adoption became widespread across the construction industry when Sir Robert McAlpine began utilising them.
Organise a Consult With a Relevant Professional
Before beginning any work, it is essential to understand:
- How much vertical weight requires support;
- Is the floor capable of supporting the weight;
- Whether Strong Boys or Timber Needles are needed; and
- How many props, Strong Boys or Timber Needles are required to safely support the load?
Sourcing a structural engineers’ opinion will help inform you of the appropriate amount of Acrow Props to use. If you are unsure where to look, many wholesale suppliers provide services with trained professionals or can refer you in the right direction.
Supporting beams, roofing or masonry without the input of an engineer is reckless. Any attempt only places the worksite, workers, and yourself at risk of injury or death.
Purchase Acrow Props With The Correct Height and Capacity
Since their creation 90 years ago, Shoring Props have sold in six standard sizes. Each size is capable of supporting the weight capacities seen in the table below.
Acrow Prop Capacity Table
Min. Height (mm)
Max. Height (mm)
Open Weight Capacity (t)
Closed Weight Capacity (t)
The weight capacity of the props in use must exceed the weight they are supporting. We always recommend additional props in the unlikely event that another fails. Taller Formwork Props trade capacity for height, meaning more are necessary for taller structures.
On most consultations, engineers will recommend an Acrow Prop for every metre, a common rule, but not always correct for the job at hand. Props should always be evenly spaced to ensure an even load.
Prepare Load-Bearing Surfaces
Further work may be required to create a load-bearing surface. The risk of collapse and injury is great if the floor joists and timber below cannot withstand the load of the props.
Any load-bearing surface must be flat, even and capable of withstanding heavy loads. Workers risk damaging the floor’s integrity even if it doesn’t collapse.
Timber floors are often susceptible to damage even when they are capable of supporting Acrow Prop loads. It is still important to conduct checks for certainty. Concrete surfaces are ideal for supporting heavy loads.
Erect The Acrow Prop Then Secure The Top And Bottom Plates
Start by lifting the inner tube and insert the prop pin to set an approximate height. The, use the handle on the adjustable collar to fine-tune the prop to the exact height required. Continue rotating to tighten, using a wrench as leverage if necessary.
Make sure the prop is firmly is plumb and cannot move. A props load-bearing capacity is severely affected when it sits at an angle beyond 1.5 degrees.
Let the load rest on the prop. The Acrow Prop itself should be supporting a structural beam or joist. Check props at the start and end of each workday and keep them set up until the completion of the project.
It’s important to stay aware that the weight props are supporting can change throughout the project. You should be mindful of this and ensure that any changes won’t exceed the load capacity of the props. Check out our quick video below as a visual guide.
Install Strongboys and Timber Needles for Supporting Masonry
An optional step that is only required when supporting masonry.
Brickwork and Masonry require these add-on tools as they need horizontal support instead of just vertical.
Strong Boys slot on top of Acrow Props and extend outwards into a removed section of brick. Multiple Strong Boys can support a brick wall above where it sits.
Timber Needles operate on the same principle and slot into where brickwork was. They act as a platform to evenly distribute weight between two props supporting the needle from below. Needles are advantageous for long-term projects with heavy loads.
Our guide will help you avoid simple mistakes and create a safe working environment.
Buy Formwork Props online or collect in-store at our Dandenong or Laverton branches in Melbourne. We also offer delivery nationwide. If you have any more questions on how to use Acrow Props, call us at 1300 622 686 or email us through our website.