Acrow props are a hugely popular form of shoring equipment used to temporarily support weight while permanent structural support is developed, refurbished, enhanced, or otherwise modified. Most commonly this shoring takes place within buildings, propping up ceilings and beams to allow for redevelopment of existing structures.
How To Use Acrow Props
How To Set Up An Acrow Prop
With 1 foot on the base of the outer tube to stabilise, lift out the inner tube to the desired height.
Take the pin and insert it into the prop, through the outer and inner tubes, locking the height in position.
Twist the collar for final adjustment.
Simple, Straightforward Design
The success of the acrow prop is, like many other effective products, down to the simplicity of the design and ease of use. Acrow props require very little in the way of training, as they are simply manufactured as a telescopic steel pole which can be adjusted to different heights and locked in place.
Acrow Working Load Capacity
One vital consideration that must be made is regarding the total load each individual prop will bear, and the safe working load of the prop in question.
“The safe working load (SWL) for a given prop varies according to the distance between its ends and the eccentricity of the load relative to the longitudinal axis of the prop.”
Essentially what this means is that acrow props can take different loads depending on the amount they are extended, and the concentricity (the load centre) of the load.
Prop Maximum Lean Angle 1.5°
Acrow props, also known as ‘Jack Posts’ are designed to bear loads vertically. A maximum of 1.5° out of plumb (off vertical) is recommended, as this drastically increases the side loading of the prop and will certainly lead to failure. Hence, the top and bottom plates of acrow props are small, square, and, unlike trench props, without claw-like grips.
British Standards (BS)
Adjustable telescopic steel struts (acrow props) are manufactured to BS EN 1065:1999. This standard requires high levels of manufacture and quality control to ensure props are built to handle the weight they are designed to, reducing any potential for risk.
Acrow Prop Use and Positioning
Calculating the weight born by an individual prop, and the locations to place props must be carried out by a certified structural engineer. It’s of the upmost importance that props are placed in order to ensure they are taking an equal (or bearable) weight, within the SWL of the props. This is in stark contrast to the practices of some uninformed parties who place them based on ease of accessibility. It’s also vital to reiterate that a prop that is not used completely vertical will put more stress on components not designed to withstand this side loading. This is when you see props bending on site; a not-uncommon phenomenon.
Is A 300mm Reach Enough?
Acrow props are often used to support lintels and other beams when brickwork is carried out. In these situations, masonry supports, such as the Propmate™, are used to create a platform to support these loads. Standard masonry supports are made from steel and designed to support 340Kgs per prop at a maximum distance of 300mm from the centre of the prop. Due to the thickness of modern home walls, with double skins of bricks, cavities, and plaster or other layers, sometimes this 300mm reach isn’t enough.
An extended masonry support, such as the MOAP MATE™, at 320mm, is a safer and more reliable choice. However, with this extended reach, a stronger prop is also required to bear the added side loading weight in this situation. This is the reason why we only sell the MOAP and MOAP MATE™ as a single package.
N.B. Also consider using acrow prop U-Heads for supporting beams.