Every concrete slab, bridge deck, or transfer beam starts its life held up by something temporary. That something is a construction shoring system — the network of steel props, frames, and jacks that carries the weight of wet concrete and formwork until the permanent structure can support itself. Get the shoring right and the pour goes smoothly; get it wrong and you are looking at settlement, deflection, or worse, a collapse. This is exactly why the EN 12812 standard exists, and why any serious contractor should understand what it requires before buying shoring equipment.
EN 12812, formally titled “Falsework — Performance requirements and general design,” is the European standard that governs the design and performance of temporary support structures. It is the reference point for engineers, fabricators, and suppliers across Europe and beyond. If you are sourcing shoring for a project that must comply with European norms — or simply want equipment built to a defensible, internationally recognised level of safety — EN 12812 is the benchmark to work to.
What EN 12812 actually covers
EN 12812 sets out the performance requirements and design methods for falsework — the temporary load-bearing structure that supports freshly placed or partially cured concrete. It defines the rules a designer must follow to produce a safe structure, and it provides the information a client needs when commissioning the design or supply of shoring. The standard deliberately stops short of formwork itself; the mould that shapes the concrete is a separate concern. What it does govern is everything underneath that mould: the props, frames, jacks, and bracing that transfer load down to the ground.
One of the most useful parts of the standard is its classification of falsework into three design classes. Class A covers simple falsework that relies on the known, tested performance of its components. Class B1 requires fully detailed limit-state design, where every member is checked against defined load cases. Class B2 is limit-state design oriented specifically toward prefabricated, proprietary equipment — the kind of modular shoring most suppliers, including Bythai, manufacture today. Understanding which class applies to your project tells you how much engineering input is required and what documentation you should expect from your supplier.
Design principles that keep shoring safe
Competent shoring design is about more than just the weight of wet concrete. A complete design accounts for several load categories: dead loads from the concrete, formwork, and reinforcement; imposed loads from workers, tools, pumps, and stockpiled materials; environmental loads such as wind and snow; indirect loads from thermal movement and differential settlement; and dynamic effects from the placement rate and pump surge. Wind is the one most frequently overlooked, particularly on medium-height work where designers assume it has little effect — an assumption that fails badly once cladding is partially fitted or the shoring stands above surrounding structures.
Lateral stability deserves equal attention. Good practice calls for shoring to be designed to resist a horizontal force equal to roughly 2.5% of the total vertical load, applied at the point of action, to account for erection tolerances and workmanship imperfections. This rule traces back to the Bragg Report that followed the 1972 Loddon Viaduct collapse, and it remains one of the quiet reasons large-scale shoring failures have not repeated at that scale. A design brief — a written document capturing scope, loads, interfaces with permanent works, and erection and dismantling sequences — is the piece most often missing when things go wrong, and it is the first thing a responsible supplier should ask for.
The components of a modern shoring system
A typical construction shoring system is built from a handful of core components, each with a specific job. The workhorse is the steel prop — a telescopic column with an outer tube, an inner tube, and a pin-and-collar mechanism that allows precise height adjustment. Because load capacity falls as the prop extends, the relationship between extended height and safe working load is the critical calculation for site engineers planning prop spacing. Heavy-duty props, built from thicker tube and rated for higher loads, are used where slab thickness or span demands more capacity.
Around the props sit the accessories that make the system usable. Adjustable shoring props pair with U-head jacks at the top, which cradle the formwork beams and allow fine levelling, and base jacks at the bottom, which spread the load onto a firm bearing surface and compensate for uneven ground. Bracing ties the whole assembly together against lateral movement. When these components are sourced as a matched set from a single supplier, the system behaves predictably — which is precisely what EN 12812’s Class B2 approach assumes.
Steel props versus traditional timber shoring
The shift from timber to steel shoring is one of the clearest safety and efficiency improvements in modern construction. Timber is prone to warping, splitting, and inconsistent load capacity, all of which create unpredictable site conditions. Steel props offer millimetre-precision adjustment through threaded collars, a consistent and certified load capacity, and the ability to be reused across hundreds of projects. A small crew can erect a large support grid in a fraction of the time timber would take, and steel is fully recyclable, cutting the material waste that timber shoring leaves behind.
What to look for in a shoring system supplier
Choosing a shoring system supplier comes down to a few verifiable facts rather than marketing claims. First, check the materials. High-grade structural steel such as Q235 or Q355 provides the right balance of ductility and tensile strength for heavy-duty shoring, and it is the material base used by reputable manufacturers. Second, check the surface treatment. Hot-dip galvanizing (HDG) gives props and jacks real corrosion resistance, which matters when equipment is stored outdoors between projects or used on exposed sites. Third, check the quality system. An ISO 9001-certified factory with documented inspection procedures is far more likely to ship consistent, traceable products than an unmanaged workshop.
Bythai Scaffolding, a China-based manufacturer with over ten years of industry experience, builds its shoring and scaffolding range from Q235 and Q355 steel with hot-dip galvanized, electro-galvanized, powder-coated, or pre-galvanized finishes. The factory is ISO 9001 certified, and products are manufactured in line with international EN and BS standards. Beyond the equipment itself, Bythai offers OEM manufacturing and flexible minimum order quantities, which makes it practical for both small contractors and large distributors to source a complete shoring package — props, U-head jacks, base jacks, and bracing — from one accountable supplier.
Inspection and safety on site
No amount of good design replaces disciplined site practice. Shoring should be inspected at three moments at minimum: before the pour, during the pour, and immediately after it. Pre-erection, reject any component that is damaged, bent, or corroded, and any item whose load data cannot be matched to the actual piece on the deck. After erection and before loading, verify that the as-built structure matches the approved design — this is the point where a written permit-to-load should be issued. During the pour, watch for settlement of the sills, visible lean in the standards, loose bracing connections, and any unplanned surcharge such as rebar stockpiles or pump-line movements that the design did not cover. Most documented shoring failures happen during concrete placement, and most of them are caught too late because nobody was watching at the moment the load ramped up.
Conclusion
A construction shoring system is only as good as the standard it is designed to, the quality of its components, and the discipline of the crew that erects it. EN 12812 gives you a clear, internationally recognised framework for all three: it defines the design classes, the load cases, and the performance expectations that turn a pile of steel tubes into a predictable, safe support structure. When you source shoring, buy from a supplier who can demonstrate compliance with that standard, who uses verified structural steel and proper galvanizing, and who can supply the full component set rather than a partial kit. That combination — the right standard, the right materials, and the right supplier — is what keeps a pour safe, on schedule, and within budget.
Frequently asked questions
What is the difference between falsework, formwork, and shoring?
Formwork is the mould that gives concrete its shape. Falsework is the load-bearing structure beneath the formwork that transfers the weight of wet concrete down to the ground. Shoring is essentially a synonym for falsework, though it is also used for propping existing structures during demolition or refurbishment. Access scaffolding is a different category entirely — it is designed for workers and light materials, not for structural load transfer, and should never be pressed into service as shoring.
How do I work out how many props I need for a slab?
Calculate the total dead load — the weight of the concrete and formwork — plus the live load from workers and equipment per square metre. Divide that total by the safe working load of a single prop at its specific extended height, then apply a safety factor of at least 1.5 to 2.0 to cover unexpected load concentrations. A professional engineer should always verify the shoring plan against the relevant local codes and the EN 12812 design class that applies to your project.
How long does a good steel prop last?
A well-maintained, hot-dip galvanized steel prop can last ten to fifteen years. The most common causes of failure are severe corrosion and physical deformation from overloading. Clean concrete residue off the tubes after each project, lubricate the threaded collars, check the locking pins for wear, and decommission any prop that has a significant bend or a distorted pin — its load capacity is permanently compromised.