Shoring versus a trench box on a Saint John sewer job?

Shoring, Trench Boxes and Saint John Sewer Work

For a sewer trench in Saint John, the choice between timber shoring and a trench box comes down to the same WorkSafeNB rule either way: any trench 1.2 m (about 4 ft) or deeper that workers enter must be shored, sloped or benched, or cut in solid rock, and any shoring or bracing must be certified as adequate by an engineer. The regulation names shoring, bracing or caging and does not pick one method over another.

Which method suits a Saint John sewer job is the contractor's and engineer's call, and the engineer's certification applies to whichever is used. If the trench is sloped or benched to within 1.2 m of the bottom at no more than 1 m of vertical rise for each 1 m of horizontal run, shoring is not required, but that geometry has to be judged on site against the available space and the soil conditions the contractor finds when they open the ground.

For a sewer connection in Saint John, the City requires a Water and Sewerage Permit Package before any new, renewal or repair installation on water, sanitary or storm sewer lines. Ask the City's permit office what that package requires for your specific connection before the machine arrives. Before any digging, the contractor must determine the location of underground utilities under WorkSafeNB's General Regulation 91-191, section 180. That means two separate requests: one through Info-Excavation (Click Before You Dig) at least three working days ahead, and a separate request to NB Power at least five business days ahead, because NB Power runs its own locate service and checks only for NB Power-owned underground power lines. Any private lines, fuel lines or drains installed by a past owner are the owner's to find and mark before the machine moves.

Stay back from the open trench edge. WorkSafeNB rules require excavated material to be kept at least 1.2 m from the edge, a ladder extending at least 1 m above the top within 15 m of any worker in the trench, and a worker on the surface who can see anyone working below. Those rules bind the employer, meaning the excavation contractor, but as the property owner you can ask to see how the contractor plans to meet them before work starts.

A fair quote for this job should spell out how the trench will be protected, who certifies the shoring or box as adequate, how rock will be priced if it is encountered, where spoil goes and at what cost, and whether the City permit fee is included or billed separately. Ask for a WorkSafeNB clearance certificate before signing, and retain 10% of the contract price as a holdback for 60 days after substantial performance, as required by the Construction Remedies Act.

Ask the contractor to name the engineer who will certify the trench protection method and confirm that certification is in writing before anyone enters the trench.

If you are ready to get quotes, the request form on this site sends your job details to local New Brunswick excavation contractors who can respond directly.