A complete guide to using props in construction

Props are a vertical support system. Before they were invented, construction professionals had to rely on timber supports and scaffolding to ensure walls didn’t collapse. Unfortunately, safety issues were rife. Timber is strong, but it is weakened by water and is vulnerable to fire. In addition, cutting wooden probs to fit the job is time-consuming. Thankfully, Acrow props were invented and life in the construction trade got a lot easier.

In this article, we are going to look at how to use Acrow props safely and effectively.

The History of Acrow Props
Acrow props were invented by William de Vigier in 1935. De Vigier understood that wooden props were not ideal, so he came up with the idea of using steel poles that could be height adjusted via a screw design. Steel was much stronger and more durable than timber, and because de Vigier’s prop was height adjustable, it could be reused time and again, which saved construction professionals a lot of money.

De Vigier needed a name for his new invention, so he hit upon the idea of using his solicitor’s name: A Crow. This had the advantage of starting with ‘A’, which meant it appeared first in a list of products.

It wasn’t long before construction professionals recognised the merits of using Acrow props instead of traditional wooden props. Sir Robert McAlpine, an early pioneer of the UK construction industry, was one of the early adopters of de Vigier’s invention. McAlpine placed orders for Acrow props to be used on all his construction sites nationwide. Others soon followed, and within a few years. Acrow props widely used everywhere.

Why Use Props?
The clue is in the name. As we have already mentioned, props are used to support a structure, or in other words, ‘prop’ it up.

In renovation jobs, it may be necessary to remove large parts of a structure. Once you dismantle walls and other supporting structures, those that are left are vulnerable to collapse. This is especially the case if you remove internal walls and/or the roof of a property. The remaining walls have very little to support them, which is a problem if they are load-bearing. So, there is a real possibility that without support, they will collapse. This is dangerous for people working in the immediate vicinity.

Acrow props are used to support the walls and prevent them from collapsing. They are often used when a door or window is knocked through a load-bearing wall. The prop takes the weight of the roof and wall above the opening while an RSJ or lintel is inserted.

What do Acrow Props Look Like?
De Vigier’s prop design is very simple. There is an inner steel tube and an outer steel tube. A top plate is welded to the inner tube and a bottom plate is welded to the outer tube. A handle and a threaded collar around the mid-section allow the prop to be extended and retracted to suit the job.

The angle of the steel base plate and top plate is adjustable, so the prop can be placed on an angle. This provides horizontal support for load bearing walls. You can also use a vertical Acrow prop to support ceilings and horizontal beams.

In de Vigier’s original design, Acrow props were used to provide vertical support, but because the design is so simple and effective, numerous variations have been spawned over the years. Today, Acrow props are used in housebuilding, civil engineering, and in any project where extra support is needed vertically or horizontally.

Horizontal strutting props are a variation on the classic Acrow prop design. These are used to support trenches during groundwork excavations.

Acrow props come in five standard sizes, ranging from size 0 to size 4.

A standard Acrow prop is ideal for everyday use, but there are heavy duty Acrow props available from suppliers like Heaton Products These are stronger and bigger than standard 60mm Acrow props. They can support two skins of bricks and have a 500kg safe working load. That is 47 per cent more than standard support props. If you need a high capacity prop, go for a heavy-duty Acrow prop.

Modern Acrow Props
De Vigier’s original design used pure steel, but these props rusted when they were exposed to the elements on construction sites. Modern Acrow props are made from galvanised steel, which is steel coated with an outer layer of zinc. This protects the prop from corrosion, thus ensuring it remains stronger for longer.

If your prop does sustain any damage or one of the parts needs replacing, this isn’t a problem. It is very easy to find replacement parts for Acrow props, which means you don’t need to buy a new one. You can also buy extra add-ons, such as timber needles and forkhead attachments. These extend the usefulness and versatility of Acrow props.

Always observe safety guidelines when using Acrow props to support masonry and concrete formwork.