ADU services in Ottawa

Second Dwelling Unit Ottawa designs, builds, and legalizes every type of Additional Dwelling Unit the City of Ottawa recognizes, under one roof.

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All ADU services

Every service we offer, in one place.

Detached, backyard

Garden Suites

Full privacy, no shared walls with the main house.

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Detached, above or beside parking

Coach Houses

Builds up over your garage instead of into the yard.

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Detached, lane access

Laneway Suites

Its own entrance and street presence off a rear lane.

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Internal conversion

Basement Apartments

The fastest, lowest-cost-per-sq-ft ADU type.

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Drawings and permits

ADU Design

Zoning-checked designs and full permit drawing sets.

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Design-build

ADU Construction

Built to the drawings and permit we filed – one team.

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Zoning and Committee of Adjustment

Legalization & Permits

Bring an existing unit up to code and on title.

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What every project includes

Feasibility review

We confirm what your lot's zoning actually permits before design work starts.

Full permit package

Architectural drawings, engineering where required, and the City of Ottawa building permit filing.

Single project lead

One team stays accountable from design through final inspection.

Getting started

Starting the conversation

Most homeowners land on this page comparing two or three options rather than certain which one they want. That is exactly what a feasibility review is for: we look at your specific lot, tell you honestly which of these four types it actually supports, and give you a realistic sense of size, cost, and timeline for each of the realistic paths before you commit to a direction, in plain language rather than zoning jargon.

The team understood Ottawa's requirements and gave us practical recommendations for our property. We are very pleased with the service.

Andrew L.

The City of Ottawa's zoning by-law recognizes four practical ways to add a second home to a residential property, and this page is the starting point for all of them. Which one makes sense for your lot depends on things a calculator or a general article cannot tell you: your property's specific zoning, how much of it is already built on, whether your basement clears the minimum ceiling height, and whether you have a garage or a rear lane to work with.

Both a garden suite and a coach house are fully detached structures, separate from the main house, which means real privacy for both households and no impact on the main house's existing living space. The difference is placement. A garden suite sits in open yard space. A coach house sits above or beside a garage, which matters on a lot where yard depth is tight but an existing or planned garage footprint has room to build up. A laneway suite is a close cousin of both, specifically oriented toward a rear service lane where one exists.

For a large share of Ottawa properties, especially older housing stock without much rear yard depth, a basement apartment conversion is the most realistic option. It uses a foundation that already exists, which generally makes it the fastest and lowest-cost-per-square-foot ADU type to build, provided the basement clears (or can be brought up to) the minimum ceiling height and can be given a proper second exit.

Every one of these paths goes through the same core steps: a feasibility review against your property's actual zoning, design and permit drawings prepared to Ontario Building Code requirements, a City of Ottawa building permit application, and construction carried out by a crew working from the approved drawings. We run all of it under one contract, so the same team that designs your unit and files the permit is the one building it.

Choosing the right ADU type

Can I have more than one Additional Dwelling Unit on my lot?

On many Ottawa residential lots, up to three dwelling units total (the main house plus two ADUs) are permitted as-of-right, subject to lot size, parking, and servicing. Zoning varies by property – a feasibility check confirms your lot's limit.

Which ADU type is cheapest to build?

A basement apartment conversion is usually the lowest cost per square foot because it reuses an existing foundation and walls. Detached units (garden suite, coach house, laneway suite) cost more per square foot but do not reduce the livable space in your main house.

What should I know about legalizing what already exists?

Not every project starts from a blank slate. If your property already has a basement apartment, a garden suite, or a coach house that was never permitted, the process is a review of what exists against current code, followed by targeted upgrades and a retroactive permit application, not necessarily a full rebuild. Our legalization service covers that path specifically.

Not sure which ADU type fits your lot?

Book a free feasibility check and we will walk you through the options that apply to your property.

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