Do you need a permit for a retaining wall in Coquitlam?
A straight answer from the Coquitlam crew that does this work. Updated November 2026.
Short answer: In Coquitlam, a retaining wall taller than 1.2 metres (4 feet) needs a building permit and must be designed by a professional engineer. Walls 1.2 m and under usually don't need a building permit, but they still have to follow City bylaws and the BC Building Code. No retaining wall can be taller than 2.4 metres (8 feet), and walls over 0.6 metres (2 feet) should have a guard or fence on top.
Source: City of Coquitlam: What restrictions apply for building retaining walls?. Rules change, so confirm with the City before you build or cut.
How the 1.2 m rule works in practice
The height that counts is the height of the wall itself. Coquitlam's slope lots on Burke Mountain, Westwood Plateau and Ranch Park often need more than 1.2 m of soil held back, so homeowners usually have two choices:
- One engineered wall over 1.2 m, with a building permit, engineer's drawings and field reviews during construction. The City caps any single wall at 2.4 m.
- Two or more shorter walls, terraced back with planting space between them. Terracing can avoid one tall wall, looks softer and gives you usable garden beds. How far apart the tiers must be before the City treats them as separate walls is set by the City, so we confirm the layout with them before we build.
Things that catch Coquitlam homeowners out
- Guards and fences. The City says walls over 0.6 m should have a guard or fence on top. Plan the fence and its posts into the wall design from the start, because a fence adds wind load.
- Trees. Digging in the root zone of a protected tree, yours or your neighbour's, can break the Tree Management Bylaw. Plan the wall around big trees, or get the tree permit first.
- Property lines. A wall built on the line, or leaning onto a neighbour's lot, becomes a shared problem. Know where your survey pins are before you dig.
- Drainage. Most walls fail because of water, not weight. Every wall needs drain rock behind it and a perforated drain pipe with a proper outlet. Without that, winter rain builds pressure behind the wall until it bulges or tips.
What a permit wall involves
For a wall over 1.2 m: a site visit and measurements, an engineer's design, the building permit application to the City, construction with the engineer reviewing key stages (footing, drainage, geogrid), and the engineer's sign-off at the end. It takes longer than a garden wall, but you get a wall that's documented when you sell the house.
Common questions
Does a short garden wall need a permit in Coquitlam?
Usually not if it's 1.2 m or less, but City bylaws, setbacks and tree rules still apply. Ask the City if you're unsure.
Can I build a 1.1 m wall now and add more later?
Stacking more on later just makes a taller unpermitted wall. Design for the final height from day one.
Does a block wall need an engineer?
Any wall over 1.2 m in Coquitlam must be designed by a professional engineer, whether it's block, poured concrete or timber.
What's the tallest retaining wall allowed in Coquitlam?
2.4 metres (8 feet). Anything taller has to be broken into terraced walls.
Who applies for the permit?
The homeowner or their contractor. We coordinate the engineer and the application on the walls we build.
Planning a wall in Coquitlam?
We build engineered and garden retaining walls across Coquitlam, Port Coquitlam, Port Moody and Maple Ridge. We'll measure your slope, tell you whether you need a permit, and give you a free written estimate.