Shoring is the process of temporarily supporting a building, structure, or trench wall to prevent collapse. It involves placing props, braces, or hydraulic systems against unstable surfaces to hold them in place during construction, excavation, or repair work. You’ll encounter the term most often in two contexts: construction and excavation safety, where physical supports keep soil and structures from caving in, and business operations, where “shoring” appears in terms like nearshoring and reshoring to describe relocating production or services.
How Shoring Works in Construction
In construction, shoring means installing temporary buttresses, typically made of timber, steel, or aluminum, to brace a structure or excavation that could otherwise shift or collapse. The supports can be vertical, angled, or horizontal depending on what needs to be held in place. A contractor might shore up a building wall during renovation, brace an adjacent structure while digging a new foundation next door, or support the walls of a trench so workers can safely operate inside it.
Shoring is distinct from underpinning, which is a permanent solution. Underpinning strengthens an existing foundation by extending it to a deeper, more stable layer of soil or rock. Shoring, by contrast, is always temporary. It stays in place only until the permanent structure can support itself or the excavation work is finished.
Trench Shoring and OSHA Requirements
Trench collapses are one of the deadliest hazards in construction, and shoring is one of the primary ways to prevent them. OSHA requires employers to protect workers from cave-ins whenever a trench is 5 feet deep or more, unless the excavation is cut entirely into stable rock. Even in trenches shallower than 5 feet, protection is required if a competent person on site sees signs that the ground could give way.
The three approved methods for protecting workers in a trench are sloping or benching the sides of the excavation to reduce pressure, installing a support system like shoring or bracing, or placing a trench shield (a prefabricated box) between the soil wall and the work area. Which method is appropriate depends largely on the soil type, which OSHA classifies into four categories:
- Stable rock: Natural solid mineral that can hold vertical sides on its own.
- Type A soil: The strongest soil category, including clay and silty clay. No soil qualifies as Type A if it has been previously disturbed or contains cracks.
- Type B soil: Moderately strong soils like angular gravel, silt, and sandy loam.
- Type C soil: The weakest and most collapse-prone category, including gravel, sand, loamy sand, and any submerged soil or soil with water freely seeping through it.
A competent person, someone trained to identify hazards and authorized to take corrective action, must classify the soil before work begins. Type C soil demands the most aggressive protection, and shoring systems used in it must be engineered to handle the higher lateral pressure.
Types of Shoring Systems
Shoring systems range from lightweight, off-the-shelf equipment to custom-engineered installations. The right choice depends on the depth and width of the excavation, soil conditions, available space, and what structures sit nearby.
Hydraulic Shoring
Hydraulic shoring is the most common system for trench work because it’s quick to install and relatively lightweight. It uses hydraulic cylinders mounted on aluminum rails or walers to press against opposite walls of a trench, holding them apart. There are three main configurations:
- Vertical shoring: Hydraulic cylinders attached to aluminum rails, typically spaced 4 to 6 feet apart depending on soil conditions. Rail sizes range from 2 feet to 7 feet and larger.
- Hydraulic walers: Cylinders attached to horizontal aluminum beams (walers) that work with sheeting materials like steel, wood, or aluminum panels to cover more of the trench wall. Waler lengths run from 6 to 10 feet or longer.
- Hydraulic aluminum boxes: Complete prefabricated units combining walers, cylinders, and wall panels into a single system. Sizes range from 6 feet to 14 feet or larger, and crews can lower them into a trench as one piece.
Engineered Shoring Systems
Larger or more complex excavations often need custom systems designed by a professional engineer for the specific project. These include driven steel sheet piling, where interlocking steel panels are hammered into the ground to form a continuous wall. H-beam systems use steel columns with wood lagging or steel plates between them. Tie-back bracing anchors the shoring wall to the soil behind it using cables or rods drilled into stable ground. Raker bracing uses angled supports from the excavation floor to the wall. In extreme conditions, slurry walls (concrete poured into a trench filled with stabilizing fluid) or even ground freezing may be used.
Shoring for Buildings and Structures
Shoring isn’t limited to trenches. Whenever construction activity threatens the stability of a nearby building, wall, sidewalk, or pavement, OSHA requires employers to install support systems to keep those structures safe. This commonly happens when a new building’s foundation is being dug next to an existing structure. The shoring transfers loads from the neighboring building through temporary props until the new construction can provide permanent support.
Building shoring also shows up during renovations. If a load-bearing wall is being removed or a floor system is being modified, temporary shores carry the weight until new structural elements are in place. These are typically steel or timber posts with adjustable jacks at the top or bottom to fine-tune the fit.
Shoring in Business and Supply Chains
Outside of construction, “shoring” appears in business terminology to describe where companies locate their operations. The three most common terms are:
- Offshoring: Relocating business operations to a distant country, usually to take advantage of lower labor costs. The trade-off can include quality control challenges and communication difficulties across time zones.
- Nearshoring: Moving operations to a nearby country, often one that shares a border or is within a short travel distance. This reduces shipping times and costs compared to offshoring while still offering some labor savings.
- Reshoring: Bringing manufacturing or services back to the home country. Companies reshore to gain tighter quality control and meet domestic regulatory standards, though labor costs are typically higher.
The choice between these strategies depends on how much a company prioritizes cost savings versus supply chain speed, production quality, and control. Nearshoring splits the difference, while offshoring maximizes cost reduction and reshoring maximizes oversight.