So, you need a retaining wall – what now?

Simply put, a retaining wall is a structure that supports lateral soil pressures to retain soil that sits at a higher elevation and a near-vertical angle.

The Ontario Building Code provides a straightforward definition of when you would need to apply for a Building Permit to construct retaining walls; HOWEVER, every municipal jurisdiction has its requirements. Therefore, it is always best to ask your City’s Building Department whether you require a Building Permit or not to construct your retaining wall.

Suppose you have an existing retaining wall less than 1 meter (3’ 3”) in exposed height at its highest point. In that case, you do not need a Building Permit to replace the retaining wall as per the Ontario Building Code.

However, if you plan on changing the existing grade on your property and installing a new retaining wall, then you would require a Site Alteration Permit to change the existing grade on your property, regardless of the height of your retaining wall.

The types of supporting documents needed to apply for a building permit will depend on the complexity and location of the proposed retaining wall structure. However, a stamped engineering drawing and a Site Plan showing the location of the retaining wall on a survey plan would be the bare minimum requirements.

If your retaining wall is on a slope or is holding back a slope or structure, then a Slope Stability Assessment by a Geotechnical Engineer and a Topographic Survey plan might be required to apply for a building permit successfully.

If trees with a diameter of 20 cm need to be removed or injured, either on public or private land, an Arborist’s Report will be required depending on the number of trees that need to be damaged or removed.

You might be far from a ravine or greenspace. Still, your property might be in a restricted zone regulated by a Conservation Authority. Regulated areas can sometimes encompass large areas several kilometers from a watercourse. Therefore, it is always a good idea to visit the website of the relevant Conservation Authority and inquire by simply entering your postal address. This quick and free service offered by most Conservation Agencies will save you many headaches and costs further along the project. Suppose your property is within a restricted zone. In that case, you must apply for a building permit from the relevant Conservation Authority to replace an existing retaining wall.

Each situation is unique, and as mentioned earlier, the type of supporting documents needed will vary depending on the location and complexity of the retaining wall. However, it would be a good idea to allocate a minimum of 6-8 months to complete these reports and for a Building Permit to be issued.

Finally, the City will likely require a Letter of Completion as a condition of the Building Permit approval. A Letter of Completion is a certified report issued by a Structural Engineer who holds a P.Eng. The engineer will review the construction of the retaining wall at different stages and certify that the retaining wall has been built as per the design and specifications approved by the City. Even if a Letter of Completion is not mandatory, it is an excellent idea to have an independent Structural Engineer review the construction of the retaining wall and issue a Letter of Completion. Also, consider it as insurance on your significant investment.

We provide in-house design services and have extensive experience working with every City in the Greater Hamilton and Greater Toronto Areas. We also offer Stamped Design drawings, Slope Stability Assessments, Arborist Reports, and Letters of Completion.

Contact us today for a free consultation. We would happily provide an innovative solution for your retaining wall project.