Do You Need a Building Permit for a Greenhouse in BC?

The short answer: if your greenhouse is 108 square feet or smaller, you probably do not need a building permit. If it is bigger, you probably do. But there are conditions, exceptions, and municipal variations that matter. This guide breaks it all down for BC.

I have built greenhouses across Vancouver Island for 10 years. The permit question comes up on every project. People either want to avoid the process entirely (understandable) or do not know it exists until they are halfway through a build. Neither situation is good. Here is what you actually need to know.

The BC Building Code Rule

The BC Building Code exempts certain small accessory structures from building permit requirements. The key threshold is 10 square metres (108 square feet) of building area.

An accessory structure that meets ALL of the following is generally permit-exempt:

• Building area does not exceed 10 m² (108 sq ft)
• Single storey only
• Not used as a dwelling or for sleeping
• Detached from the principal building (not attached to the house)
• Does not contain plumbing fixtures requiring drainage
• Does not contain electrical wiring (or electrical is installed by a licensed electrician under separate electrical permit)

A greenhouse that fits these criteria does not require a building permit under the provincial code. But -- and this is important -- your municipality can impose additional requirements. The BC Building Code sets the floor, not the ceiling.

What "Accessory Structure" Means

An accessory structure is a building that is secondary to and supports the principal use of the property. On a residential lot, the principal building is your house. A greenhouse, garden shed, workshop, or storage building is accessory to it.

For the permit exemption to apply, the structure must be:

• Detached: Physically separate from the house. A greenhouse attached to your house wall is an addition, not an accessory structure, and always requires a permit.
• Subordinate: Smaller and secondary to the main building.
• Consistent with zoning: The use must be permitted in your zone. Greenhouses are typically allowed in all residential zones, but check your zoning bylaw.

Permit-Exempt vs Permit-Required: Comparison

Feature	Permit-Exempt (108 sq ft or less)	Permit-Required (over 108 sq ft)
Maximum size	10 m² (108 sq ft)	No maximum (zoning limits apply)
Building permit	Not required	Required -- plans, fees, inspections
Setbacks	Still must comply with zoning setbacks	Must comply with zoning setbacks
Height limit	Single storey (typically 3.5-4.5m max)	As per zoning bylaw (accessory building height)
Plumbing	Not permitted (or separate plumbing permit)	Permitted with plumbing permit
Electrical	Separate electrical permit required	Included in building permit scope
Structural inspection	None	Foundation, framing, and final inspections
Engineered plans	Not required	May be required depending on size/municipality
Timeline	Build when ready	2-8 weeks for permit approval, then build
Cost (permit fees)	$0	$200-$800+ depending on municipality and value
Lot coverage	Counts toward lot coverage maximum	Counts toward lot coverage maximum
Attached to house	Not allowed -- must be detached	Allowed as addition (different code path)

The 9x12 Greenhouse: Designed for the Threshold

Our 9x12 backyard greenhouse is specifically sized at 108 square feet -- right at the permit-exempt threshold. This is not a coincidence. It is the largest greenhouse you can build without triggering the permit process in most BC municipalities.

At 9 feet wide by 12 feet long:

• Floor area: 108 sq ft (10.0 m²)
• Single storey (south wall 9 ft, north wall 7 ft)
• Detached structure on sono tube piers
• No plumbing (hand-watering or hose connection does not count as plumbing)
• No electrical required (manual vents, passive solar heating)

This gives you a functional growing space -- enough for a 1-2 person household to produce year-round greens, herbs, and season-extended tomatoes -- without paperwork, permit fees, inspections, or delays.

For more detail on the rule itself, see: The 108 Square Foot Rule: Building Without a Permit in BC

When You DO Need a Permit

You need a building permit for a greenhouse when any of the following apply:

1. Over 108 sq ft: Our 14x20 production unit at 280 sq ft requires a permit. So does any greenhouse larger than 9x12.
2. Attached to your house: A lean-to greenhouse on the south wall of your home is an addition to the principal building. Always requires a permit.
3. Contains plumbing: If you are running drain lines, a sink, or in-floor heating connected to household plumbing -- permit required.
4. Multi-storey: Any structure with a loft, mezzanine, or second level.
5. Your municipality has stricter rules: Some municipalities require permits for all accessory structures regardless of size. Check locally.

Setback Requirements

Even permit-exempt structures must comply with municipal setbacks. These are minimum distances from property lines that your structure must maintain. Setbacks are set by the municipal zoning bylaw, not the building code.

Typical Vancouver Island Setbacks for Accessory Structures

Municipality	Rear Setback	Side Setback	Front Setback
Campbell River	1.5 m	1.5 m	Same as principal building
Courtenay	1.5 m	1.5 m	Same as principal building
Nanaimo	1.5 m	1.5 m	Same as principal building
Comox Valley RD (rural)	1.5 m	1.5 m	7.5 m from road
Strathcona RD (rural)	1.5 m	1.5 m	7.5 m from road

Important: These are typical figures. Your specific lot may have different setbacks based on zoning designation, lot size, or easements. Always check your property's zoning bylaw before placing a structure. A 5-minute call to your local building department confirms the setbacks for your lot.

Other Placement Rules

• Cannot be in a utility easement (check your title for registered easements)
• Must be at least 3 metres from a septic field
• Cannot block sight lines at road intersections or driveways
• Must not exceed lot coverage maximums (typically 35-50% in residential zones)

ALR (Agricultural Land Reserve) Considerations

If your property is in the Agricultural Land Reserve, greenhouses are generally permitted as farm use. You do not need Agricultural Land Commission (ALC) approval to build a greenhouse for growing food -- it is a permitted agricultural activity.

However:

• ALR status does not override building code requirements. You still need a building permit if the greenhouse exceeds 108 sq ft.
• Very large commercial greenhouse operations (thousands of square feet) may need to demonstrate they qualify as farm use.
• If the greenhouse is for non-farm purposes on ALR land (e.g., a retail space), that may require ALC approval.
• ALR properties still have setback requirements under regional district zoning bylaws.

For most small-farm and homestead greenhouses on ALR land, the path is straightforward: build at 108 sq ft or less with no permit needed, or get a building permit for larger structures. The ALR designation does not complicate things -- if anything, it simplifies them because agricultural use is explicitly permitted.

Municipal Variations

The BC Building Code provides the baseline rules, but municipalities can be stricter. Here are variations I have encountered across Vancouver Island:

• Some municipalities require a "building notification" even for exempt structures: Not a permit, but a form telling them what you are building and where. No fee, no inspection, but they want a record.
• Some cap total accessory building area: You might be limited to 50 m² total accessory structure footprint on your lot, regardless of whether individual structures are under 10 m².
• Height limits vary: Some allow 4.5 metres for accessory structures, others cap at 3.5 metres. A 9-foot south wall greenhouse fits under both.
• Heritage areas or design-controlled zones: May have appearance guidelines even for accessory structures.
• Fire interface areas: Properties in wildfire interface zones may have additional requirements for combustible materials and setbacks from vegetation.

The consistent advice: call your local building department before you start. A 5-minute phone call can save you from a stop-work order or forced removal later.

The Permit Process (When Required)

If your greenhouse exceeds 108 sq ft, here is what the permit process typically involves:

1. Prepare drawings: Site plan showing location on lot with setback dimensions. Floor plan. Elevations (front, side). Cross-section showing foundation detail. Materials list.
2. Submit application: Bring drawings plus application form to your local building department. Pay the permit fee ($200-$800 depending on municipality and project value).
3. Review period: 2 to 8 weeks depending on municipality workload and drawing quality.
4. Permit issued: You receive an approved set of drawings and a permit card to post on site.
5. Build: Construct according to approved plans.
6. Inspections: Typically 2-3 inspections: foundation (before backfill), framing (before cladding), and final.
7. Occupancy: Final inspection passed -- structure approved for use.

For a standard greenhouse in the 200 to 600 square foot range, this process is not complicated. The drawings do not need to be architect-prepared -- clean hand drawings with accurate dimensions are accepted by most building departments on Vancouver Island.

Electrical and Plumbing: Separate Permits

Even in a permit-exempt greenhouse, if you want to run electricity (for a fan, lights, or heating), you need a separate electrical permit. The electrical work must be done by (or inspected by) a licensed electrician. The electrical permit is separate from the building permit -- the two are independent.

Plumbing (running water lines to or from the greenhouse for sinks, drains, or in-floor heating) requires a plumbing permit. A garden hose connection does not count as plumbing.

Neither of these triggers a building permit for the structure itself -- they are separate permits for the trade work only.

What Happens If You Build Without a Required Permit

If you build a greenhouse over 108 sq ft without a permit and the municipality finds out:

• You may receive a stop-work order
• You may be required to apply for a permit retroactively (with additional fees -- often double the standard permit fee)
• If the structure does not meet code, you may be required to modify or remove it at your cost
• It will not show on your property assessment, which can create problems at sale

The penalty varies by municipality and circumstance. In practice, many small greenhouses fly under the radar indefinitely. But if a neighbour complains, or you try to sell the property, unpermitted structures become a problem. It is cheaper to get the permit upfront than to deal with enforcement later.

Our Approach

At Swell Farms, we offer two standard greenhouse sizes specifically because of the permit threshold:

• 9x12 backyard greenhouse (108 sq ft): Permit-exempt. Build it and start growing. No paperwork, no fees, no delays. Read: Passive Solar Greenhouse Design for Coastal BC
• 14x20 production unit (280 sq ft): Requires a permit. We handle the permit research and drawings as part of the project scope. The structure is designed to standard framing practices that pass inspection without issues.

Both sizes are built as detached structures on sono tube pier foundations. No plumbing. Passive ventilation (no electrical required for basic operation). This keeps the 9x12 cleanly within the permit-exempt category.

Checklist: Before You Build

• Confirm your lot's zoning designation (residential, rural, ALR?)
• Check setback requirements for accessory structures in your zone
• Check lot coverage maximum -- will the greenhouse push you over?
• If over 108 sq ft: apply for building permit before starting
• If under 108 sq ft: confirm your municipality accepts the provincial exemption (most do)
• Check for registered easements on your title
• Stay 3+ metres from septic fields
• If adding electrical: apply for electrical permit separately