All-steel adjustable props (often referred to as acrow or ‘acro’ props) are the most common form of support prop used and are available in five different sizes.
The base and top plate of a steel adjustable prop are quite small.
Steel adjustable props are popular on construction sites, often used as a support when building.
All-steel adjustable props are stronger than adjustable support props as they are made completely from reinforced steel.
Unlike push pull props, however, they can only be used in a vertical position as the feet are fixed.
What applications are they suited to?
Steel adjustable props can be used in most forms of construction as they support horizontal loads. They can be used as a:
Temporary support
Formwork reinforcing support
Floor support, transferring loads from one level to another
Slab reinforcement
What sizes do they come in?
Size
Closed
Open
No.0
1.1m (3.5ft)
1.8m (6ft)
No.1
1.75m (5.75ft)
3.12m (10.25ft)
No.2
2m (6.5ft)
3.4m (11ft)
No.3
2.4m (8ft)
4m (13ft)
No.4
3.2m (10.5ft)
4.9m (16ft
Which size should you choose?
When selecting a prop, two things need to be considered: the height that the prop needs to reach and the weight it needs to support.
Prop Size
Safe working load unextended
Safe working load maximum extension
No.0
42Kn (4.2 tons) at 1.1m (3.5ft)
22Kn (2.2 tons) at 1.8m (6ft)
No.1
34Kn (3.4 tons) at 1.75m (5.7ft)
12Kn (1.2 tons) at 3.2m (10.4ft)
No.2
39Kn (3.9 tons) at 2m (6.5ft)
11Kn (1.1 tons) at 3.4m (11.1ft)
No.3
35Kn (3.9 tons) at 2.4m (7.8ft)
7Kn (0.7 tons) at 4m (13ft)
No.4
20Kn (2 tons) at 3.2m (10.4ft)
7Kn (0.7 tons) at 4.9m (16ft)
What attachments can be used?
Fork heads
Most steel adjustable props are suitable for use with the fork head attachment.
Using the fork head means that beams or other thin materials can be lain across it with more security than if just supported by the prop plate.
The fork head is usually made of steel and can be available with a zinc coating.
What are the advantages?
There are many different sizes, so it’s easy to find the height required.
They can hold a large weight (up to 4.2 tons).
The baseplate has notches which allow a number of props to be stacked horizontally when not in use.
What are the disadvantages?
It’s only suitable for use with horizontal loads and is at risk of toppling over if there is a sideways force.