Struts & Shoring Props: The Complete Guide

Every strut or shoring prop on a site does the same basic job. It holds something up, or holds something apart, until the structure around it can stand on its own. That might be a floor slab during a concrete pour, a trench wall during an excavation, or a leaning masonry wall waiting on a permanent repair. Get the right prop in the right place and the site stays safe. Get it wrong and you are looking at a collapse.

This guide covers what struts and shoring props are, why choosing the right one matters, the main types used on UK sites, and how to source them for your project from Altrad Generation.

In construction, a strut is a structural member that works in compression. It resists a load that would otherwise push it inward or make it buckle. A shore is the older, more traditional word for the same idea, a timber or metal prop used to hold a wall, floor, or structure in place while it is unstable or being altered. Shoring up a structure simply means putting one or more of these props into position to stop it moving or collapsing.

On a modern UK site, struts and shoring props usually take the form of purpose made adjustable steel equipment rather than timber. Acrow props, sometimes called shore props, support floors, ceilings, and formwork. Trench struts hold the walls of an excavation apart during trench shoring. Push pull props brace vertical formwork during a concrete pour. Each one does the same underlying job as a traditional timber shore, just with an adjustable steel design built for repeated use across different sites and different jobs.

They prevent collapse. A wall being altered, a floor carrying a fresh concrete pour, or a trench with exposed vertical sides all have one thing in common. Without support, they can fail suddenly and without warning. Struts and shoring props hold the load until the structure is stable enough to support itself, which is why the Construction (Design and Management) Regulations 2015 and HSE excavation guidance treat proper propping and shoring as a basic safety requirement rather than an optional extra.

The load has to match the equipment. A prop or strut rated for one job can fail badly in another. Using an acrow prop where a trench strut is needed, or undersizing a prop for the load above it, is one of the most common causes of propping failure on site.

The right equipment speeds up the job. Purpose made adjustable props and struts install faster and more predictably than improvised timber shoring, reducing the time a trench or opening is left unsupported.

Compliance is not optional. Struts and props used for structural support should carry a recognised British Standard mark, giving both the site team and the principal contractor confidence that the equipment has been tested to a known benchmark.

Acrow Props (Adjustable Steel Props)

The most common shoring prop on any UK site, used to support floors, ceilings, openings, formwork, and temporary beams. Acrow props from Altrad Generation are manufactured to BS4074:1982 and tested to BS5507-3:1982, and are available in five sizes covering heights from 1040mm to 4880mm.

Adjustable Push Pull Props

Formwork bracing props built for precision control during vertical formwork and shuttering. A dual collar system, standard and locking, gives maximum stability, while 150mm by 150mm base and head plates anchor the prop securely to floor or wall. Available in five sizes with a safe working load of 7kN to 32kN depending on size and extension.

Strongboy Wall Support and Strongboy Wall Support XL

A prop head that turns a standard Acrow Prop into a purpose built masonry shoring system, used to support brick and block walls during alterations, underpinning, and refurbishment. The standard Strongboy is rated to 340kg safe working load per unit, spaced no more than 900mm apart. The Strongboy XL is the heavier duty version, built for walls up to 300mm thick.

Trench Struts

Used to brace the opposing walls of an excavation during trench shoring, holding trench sheets or box linings tightly in place to prevent collapse. Trench struts from Altrad Generation are manufactured to BS4074:2004, deliver a safe working load of 3 tonnes at any extension length, and come in four sizes covering trench widths from 320mm to 1730mm. Clawed base and head plates grip the trench lining firmly, and every strut is thread rolled rather than cut, so no strength is lost in manufacture.

Alloy Waler Rails

A two sided hydraulic trench shoring system used as an alternative to a trench box where cross services or ground movement rule one out. Lightweight aluminium rails from 2000mm to 5000mm work with hydraulic cylinders to brace trench sheets across widths from 530mm to 2010mm, at a fraction of the weight of a steel alternative.

Match the equipment to the load. Check the safe working load of any prop or strut against what it actually needs to carry, and never substitute one type of prop for another because it happens to be on site.

Choose the right product family for the job. Acrow props for general floor, ceiling, and formwork support. Push pull props where precision alignment of formwork matters. Strongboy for masonry wall shoring. Trench struts or alloy waler rails for excavation and trench shoring.

Check for the standard mark. Confirm the equipment carries the relevant British Standard, BS4074 for props and struts, and has not been damaged, bent, or repaired in a way that could affect its rated performance.

Decide between hire and purchase. For a single project or short term need, hiring struts and shoring props is usually the most practical option. For continuous programmes of work, purchasing stock can be more cost effective over time.

Altrad Generation supplies the full range of struts and shoring props for hire and sale across the UK, including:

Acrow Props: five sizes, BS4074:1982, BS5507-3:1982.

Adjustable Push Pull Props: precision formwork bracing, dual collar system.

Strongboy Wall Support: 340kg safe working load masonry prop head.

Strongboy Wall Support XL: heavy duty version for walls up to 300mm thick.

Trench Struts: 3 tonne safe working load, BS4074:2004.

Alloy Waler Rails: two sided hydraulic trench shoring system.

Contact Altrad Generation to discuss your project requirements and get a quote.

Struts and shoring props rarely get noticed on a finished site, but they carry real consequences if the wrong one is used or the load is misjudged. Matching the right prop, strut, or shoring method to the job, and confirming it carries the standard mark it should, keeps the site safe and the work moving. Altrad Generation supplies the full range of struts and shoring props for hire and sale across the UK. Contact your local branch to discuss your requirements.

Q. What is a shore prop?
A. A shore prop, sometimes written as one word, is another name for an adjustable steel prop such as an Acrow prop. The term comes from shoring, the practice of temporarily supporting a wall, floor, or structure with props while it is unstable or being altered.

Q. What is the difference between a raking shore and a flying shore?
A. Both support a wall using angled or horizontal props rather than a vertical one. A raking shore runs from ground level up to the wall at an angle, typically between 45 and 75 degrees, and is used to support a single leaning or unstable wall. A flying shore runs horizontally between two buildings without touching the ground, and is used to support two parallel walls when the building between them is being demolished or altered.

Q. What is trench shoring?
A. Trench shoring is the practice of bracing the walls of an excavation to prevent them collapsing while people are working inside it. Trench struts and hydraulic waler systems are both used to shore a trench, holding trench sheets or box linings firmly against the excavation walls.

Q. What does shoring up mean in construction?
A. Shoring up means putting props or struts into position to support a structure that is at risk of moving or collapsing. It is most commonly used to describe supporting a wall, floor, or excavation during construction, alteration, or repair work.