Free tool for UK builders

Batter, step or support? Excavation selector

Answer six questions about your excavation. You will see which approaches are worth discussing with a competent person, the points to raise, and a record you can print. A competent person decides the actual profile and support for the ground on the day. This tool does not give angles, depths or distances.

The three approaches

Battering, stepping and support are the usual ways to stop the sides of an excavation falling in. They can be combined, for example stepping the top of a dig and supporting the bottom. Which one fits depends on the ground, water, loads near the edge, nearby structures and the room you have.

Batter back the sides

Battering means cutting the sides back to a slope. CDM 2015 names battering, and supports, as ways to stop an excavation collapsing where necessary. (CDM 2015 reg 22(1))

Step (bench) the sides

Stepping (benching) cuts the sides back in a series of steps instead of one slope. Each face still relies on the ground standing at that height. (CDM 2015 reg 22(1))

Support the sides (trench box, or trench sheets and props)

HSE says: “Before digging any trench pit, tunnel, or other excavations, decide what temporary support will be required and plan the precautions to be taken.” It also says to make sure the equipment is on site before work starts. (HSE, Excavations)

The selector does not give angles, depths or distances, and it does not pick the method for you. HSE says no ground can be relied upon to stand unsupported in all circumstances, so the answer for your excavation comes from a competent person who has seen the ground.

What the law says

Regulation 22 of CDM 2015 covers excavations. It says all practicable steps must be taken to prevent danger, “including, where necessary, the provision of supports or battering”, so that the excavation does not collapse, no material falls in, and nobody is buried or trapped.

It also requires steps to stop people, equipment and material falling in, and, where necessary, to stop the excavation or the ground next to it being overloaded. Where supports or battering are provided, no one works in the excavation until a competent person has inspected it and is satisfied it is safe: at the start of each shift, after any event likely to have affected its strength or stability, and after any material falls or is dislodged.

The law does not choose the method. Whether the sides are battered, stepped or supported, the profile has to stop a collapse in the actual ground. Read more in HSE’s guidance on excavations.

Write the method down

Draft the excavation RAMS

Once the method is agreed, set it out in a risk assessment and method statement. Draft one from a plain-English job description, then review and adapt it for your site.

Free RAMS generator →