City of Nanaimo permit guide
Basement conversion permits in Nanaimo
What the City asks for when you finish a basement or turn it into a suite, and the order the steps happen in.
In Nanaimo, finishing a basement or converting it to a secondary suite needs a building permit from the City of Nanaimo before construction starts. The City requires a permit for changes to an existing unit, including partition walls, ceilings and plumbing work, and a permit for building a new suite or upgrading an existing one. An application includes the building permit application form and designer-quality drawings. If you are adding or changing windows, it also includes an elevation drawing showing the new window locations. Only one suite is allowed per dwelling, and a suite counts as legal only if it was built under a building permit. Paying utility charges for a suite does not make it legal. If your property is in Cedar, Nanoose Bay or another electoral area, the Regional District of Nanaimo issues the permit instead.
Most delays on a basement conversion come from drawings that miss something the City needs, not from the construction. This guide covers what the City of Nanaimo publishes about basement and suite permits, and how we prepare an application so it doesn't come back for revisions.
Basement finish or secondary suite: which permit you are applying for
Finishing a basement as more living space for your own household, such as a family room, a bedroom or a bathroom, is a change to an existing unit, and the City of Nanaimo requires a building permit for it. A secondary suite is a separate dwelling unit with its own cooking facilities, and it comes under the City's Secondary Suite Permit, with BC Building Code requirements for the separation between the two units. The City publishes a Secondary Suites in Existing Dwellings handout and a Building Code and Zoning Requirements handout for suites, read alongside its Home Suite Home guide. We decide which applies at design, because the suite requirements shape the drawings from the start.
What the drawings have to show
The City's Plan Requirement Checklist asks for designer-quality plans drawn to scale. Graph-paper sketches are not accepted. The items it lists as frequently missed are the ones that send an application back: ceiling heights in every room, including crawl space height, all plumbing fixtures with rough-ins shown as dashed lines, the furnace, fireplace and hot water tank with drain pan and seismic strapping, exhaust fans ducted to the outside for the range hood and each bathroom, and the beams, joists and their spacing in the structure above. For a basement, ceiling height and bedroom egress windows are the two things we measure most carefully, because those decide what the rooms can legally be used for.
Existing suites, and whether yours is legal
If your house already has a suite and you aren't sure whether it's authorized, the City's Building Inspections office can tell you whether it was built under a building permit. Paying utility charges for a suite does not make it legal. Bringing an existing suite up to standard is also done under the Secondary Suite Permit. That usually means work on fire separation, smoke alarms, egress and ventilation, and the scope depends on what is behind the existing finishes.
Where basement conversions in Nanaimo get held up
Permit processing times have been in the local news through 2026, and the City does not publish a processing target for residential applications. Two things are in your control: a complete application, and decisions made before it goes in. A set of drawings that answers the checklist the first time, with the window, ceiling height and egress questions already settled, avoids the revisions that add weeks. We treat permitting as a variable in your schedule rather than a fixed block.
The steps, in order
Confirm the authority and the zoning
We check the parcel against the city boundary first, because a Nanaimo mailing address doesn't settle it. Then we confirm the zoning allows a suite and that there isn't already a carriage house on the lot, because the City allows only one suite per dwelling.
Measure the basement as it stands
Ceiling heights, including under ducts and beams, existing window sizes and locations, the moisture history, and the location of the furnace and hot water tank. Anything built before 1990 also gets a hazardous materials inspection before demolition.
Prepare the drawings
Foundation, floor and roof plans at 1/4 inch to 1 foot or 1:50, with room names, sizes and ceiling heights, door and window sizes, all plumbing fixtures, the exterior exhaust fans, smoke alarms, and the structure above. Point loads over 2,000 lbs are shown with a load path down to the foundation. If windows change, an elevation drawing is added.
Submit the application
The application goes in online with a clean PDF set of plans, plus an Appointment of Agent form if we file on your behalf. Electrical and gas work are permitted and inspected separately from the building permit.
Inspections, then occupancy
Each stage clears its inspection before the next one covers it up: framing, plumbing and mechanical rough-in, insulation and vapour barrier, then the final. Once the final inspection passes, the suite is on record as authorized.
Common questions
- Do I need a permit to finish my basement in Nanaimo?
- Yes. Inside the city boundary, the City of Nanaimo requires a building permit for changes to an existing unit, including partition walls, ceilings and plumbing alterations. That covers framing out rooms, adding a bathroom and finishing walls and ceilings.
- What drawings do I need for a basement suite permit in Nanaimo?
- Designer-quality floor plans drawn to scale, showing room sizes and ceiling heights, doors and windows, all plumbing fixtures, mechanical equipment, exhaust fans, smoke alarms and the structure above, plus an elevation drawing if any windows are added or changed. The City publishes sample plans that show the level of detail it expects.
- Can I have a basement suite and a carriage house?
- No. The City of Nanaimo allows only one suite per dwelling, so if you have a suite in your basement, a carriage house is not allowed.
- Is my existing basement suite legal?
- Only if it was built under a building permit. Paying utility charges for a suite does not make it legal. The City's Building Inspections office can confirm whether a permit is on file for your address.
- What does a basement conversion cost in Nanaimo?
- A finished lower floor commonly runs $60,000 to $140,000. Underpinning to gain ceiling height, perimeter drainage and new egress openings push a project toward the top of that range. City permit fees are set by the Fees and Charges Bylaw and sit on top of construction costs.
Sources
Related: basement renovations · bathroom renovation in Nanaimo · home renovations in Nanaimo · the renovation process · Cedar
Send us the address and what you want the basement to become, and we will confirm the permit route before anything is drawn. The questionnaire takes about two minutes.
Project inquiry
Tell us about the project
Five questions covering scope, budget, timeline and property. Enough for us to tell whether we are a fit for your project before either of us books a site visit.
Planning a major renovation?
Start with the project questionnaire — five questions covering scope, budget, timeline, and property. That tells us whether we're a fit for your project before either of us books a visit.