How To Install Acrow Props?

Acrow props have been in use all across the world. Swiss-born William de Vigier invented them after moving to London in the 1930s. Sir Robert McAlpine, a leading construction magnate, adopted the Acrow prop as a superior alternative to timber-based, one-time-use props – and it’s been popular for shoring up and repairing structures ever since. So, how do you install acrow props?

If you are about to install Acrow props (sometimes called a jack post, shore prop or adjustable prop) for your next project, there are several things you’ll need to know about using them. In this guide, we’ll discuss everything that you need to know about installing them. Let’s get into it.

Start By Consulting With A Structural Engineer

Before you use an Acrow prop, the first thing you should do is consult with a structural engineer. Or from a reputable supplier that can measure the load that your Acrow props will have to support. Giving you the information that you need to purchase or rent the appropriate number of props.

You should never attempt to support a load, such as a load-bearing beam, roof, or masonry wall, without working with a qualified structural engineer. If you do so, you are placing yourself, your workers, and the property upon which you are working at risk.

Always consult with an engineer – before you do anything else. Then, move on to the next step.


Get The Acrow Props You Need For Your Load Capacity And Height Needs

Acrow props have been standardized for several decades. However, there are many variations between manufacturers. The most common standard sizes are:

  • Size 0 – 1.1 metres to 1.8 metres. Max load: 3,300 kgs
  • Size 1 – 1.75 metres to 3.12 metres. Max load: 2,540 kgs
  • Size 2 – 2.0 metres to 3.4 metres. Max load: 2,340 kgs
  • Size 3 – 2.4 metres to 4.0 metres. Max load: 2,010 kgs
  • Size 4 – 2 metres to 4.9 metres. Max load: 1,300 kgs

The taller the Acrow prop, the lower the load it can handle – so you’ll need more Acrow props for your project if you must brace and lend vertical support to a very tall structure, such as an arched cathedral ceiling.

The total weight capacity of your Acrow props must exceed the weight that they will be supporting. As a rule, it’s never a bad thing to invest in more Acrow props – this ensures that a single prop failure (which is rare) will not result in a cascading failure.

Make Sure You’ve Got A Stable, Load-Bearing Surface For The Prop

Again, you may need to consult with a structural engineer for this step if you are working inside. You need to make sure that the floor joists and timbers can take the load of the Acrow props.

The surface upon which the Acrow props rest must be completely level and even and able to bear the load of all of the props.

Consequently, If you skip this step, you may end up damaging the floor, or destroying the structure that you are supporting completely.

Erect The Acrow Prop And Secure The Bottom And Top Plates

Next, use the pin of the Acrow prop to set the proper height. Then, using the adjusting nut, you can fine-tune the height of the prop, to make sure that it’s the exact height that is required. Lock the nut in place, tightening it with a wrench.

Then, raise the prop, TBolts or nails should secure the bottom. The top should also be secured in the same manner as a timber or structural beam unless the Acrow prop is supporting masonry.

You’re done! Let the load rest on the Acrow prop, and regularly check it for safety, until your project has been completed.

(Optional) Use A Strongboy Or Timber Needles To Support Masonry

Strongboys or timber needles are required when supporting brickwork or masonry.

A strongboy is a thin metal plate that mounts to the top of the Acrow prop and is inserted into the wall after removing some mortar or bricks. It supports all of the brick and masonwork above it, and several can be used to secure an entire brick wall.

Timber needles are similar but are usually constructed from structural timbers in a platform shape and are inserted after brickwork has been removed. Often, timber needles are built to be supported by multiple Acrow props and are better if very large loads must be supported for an extended period of time.

Stay Safe – Follow This Installation Guide!

In addition, with this step-by-step guide, you’ll be able to use Acrow props to their full potential. So don’t make common mistakes that could put your workers – and your reputation – at risk. At Australian Scaffold, we have the best selection to buy Acrow props in all of Australia.

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Do you have any questions about buying or using an Acrow prop? Give us a ring now at 1300 919 905 to get more information, or contact us online to learn more.