What building permit is required to install a concrete retaining wall over 1 metre high in Dieppe and who inspects it?

In Dieppe, retaining walls over 1 metre (3.3 feet) in height typically require a building permit from the City of Dieppe, and walls over 1.2 metres (4 feet) generally require engineered drawings in addition to the permit.

The City of Dieppe Building Inspection Department handles permit applications and inspections for retaining walls. You'll need to submit an application that includes site plans showing the wall location, height, length, and proximity to property lines. For walls exceeding 1.2 metres, you'll also need structural drawings stamped by a Professional Engineer licensed in New Brunswick, as these walls must be designed to resist significant soil pressure, water pressure, and frost heave forces.

New Brunswick's frost conditions make retaining wall engineering critical. With frost depths reaching 4 feet (1.2 metres) in the Dieppe area, improperly designed retaining walls face enormous pressure from frost heave — the upward and outward movement of freezing soil. A wall that seems stable in summer can bow, crack, or topple during the freeze-thaw cycles between November and April. The engineering requirements aren't bureaucratic red tape — they're essential for preventing expensive failures that can damage neighboring properties, utilities, or structures.

The inspection process typically involves two stages: a footing inspection before concrete is poured (ensuring proper depth below the frost line and adequate bearing on undisturbed soil), and a final inspection after wall completion. The inspector verifies that the wall matches the approved plans, includes proper drainage (weeping tile and gravel backfill), and meets setback requirements from property lines. Most municipalities require retaining walls to be set back at least half their height from property lines.

For walls under 1 metre, permits are generally not required, but you still must comply with property line setbacks and ensure proper drainage to prevent water from flowing onto neighboring properties. Even shorter walls benefit from professional design in Dieppe's clay soils, which retain water and create significant hydrostatic pressure during spring thaw.

Contact the City of Dieppe Building Inspection Department at (506) 877-7900 or visit their offices at 33 Acadie Avenue to confirm specific requirements for your project. Permit fees typically range from $100-$300 depending on wall size and complexity, plus engineering costs of $1,500-$3,000 for walls requiring professional design.

This is definitely professional territory — retaining wall design, excavation to frost depth, proper drainage installation, and concrete placement require specialized knowledge and equipment. The consequences of retaining wall failure extend beyond your property and can create liability issues with neighbors.

Need help finding a qualified concrete contractor experienced with engineered retaining walls? New Brunswick Concrete can match you with professionals through the New Brunswick Construction Network who understand Dieppe's soil conditions and municipal requirements.