Do you need a permit for a bunkie in Ontario? The short answer: in Ontario you can build a detached storage shed of up to 15 m² (161 sq ft) without a building permit, but a bunkie used for sleeping is treated differently. Whether your bunkie needs a permit depends on its gross floor area, whether it has plumbing or heat, what it is used for, and how your municipality applies the Ontario Building Code. This guide walks through each of those tests so you can size your building with confidence before you order a kit.
This article is general information, not legal advice. Building departments interpret the rules locally, so always confirm with your municipality before you build.
The quick answer: maximum shed size without a permit in Ontario
Since 29 April 2022, the Ontario Building Code exempts small storage sheds from needing a building permit when all of these are true:
- The gross area is no more than 15 m² (161 sq ft).
- It is one storey high.
- It is not attached to the house or any other structure.
- It is used only for storage, ancillary to the main building on the lot.
- It has no plumbing.
Any other small building, whatever its use, is generally exempt only up to 10 m² (108 sq ft) and again only if it has no plumbing. That older 10 m² line is the one most people mean when they talk about the “no-permit bunkie”.
| Building | Permit-free up to | Key conditions |
|---|---|---|
| Detached storage shed | 15 m² (161 sq ft) | One storey, detached, storage only, no plumbing |
| Other small accessory building (bunkie, studio, sauna) | 10 m² (108 sq ft) | No plumbing; local rules may add more |
| Anything with plumbing | No size exemption | Building permit required |
| Attached garage, carport or room | No size exemption | Treated as an addition to the house |
Do you need a permit for a bunkie in Ontario?
A bunkie is a small, detached building that people sleep in. That last part is what matters. The 15 m² exemption was written for storage sheds, so a bunkie with beds in it does not automatically qualify, even if it is the same size as a shed next door.
In practice you will run into three situations:
- Under 10 m² (108 sq ft), no plumbing. Most Ontario building departments will not require a building permit. This is why many of our cabins up to 108 sq. ft. are sized the way they are.
- Between 10 and 15 m² (108 to 161 sq ft), no plumbing. Grey zone. Some municipalities read the 15 m² exemption strictly as storage-only and will ask for a permit if you plan to sleep in it; others apply a broader “personal use” reading. Ottawa’s December 2025 advisory, for example, allows up to 15 m² for personal use ancillary to a house but says the building must not be heated.
- Over 15 m², or any size with plumbing. A building permit is required. Some townships go further and require a permit and site plan approval for every bunkhouse regardless of size, so a phone call to the building department is always worth it.
How big of a shed can you build without a permit in Ontario? Watch the “gross area”
The code measures gross area, which building officials normally take from the outside faces of the exterior walls. Kit sellers, including us, usually advertise the interior floor area, because that is the space you actually use.
The difference is not trivial. On a solid-log building the walls, corners and overhanging log ends add to the outside footprint. A kit advertised as 9.7 m² inside can measure more than 10 m² outside. Before you rely on an exemption:
- Check the external wall dimensions in the product specifications, not only the floor area in the product name.
- Multiply length by width of the outside of the walls to get the footprint.
- Ask your building department whether a roof overhang or an open porch counts toward gross area in your municipality. Many do not count an open porch, but some do.
If you are close to the limit, pick the next size down, or contact us for the exact external dimensions of the model you are considering.
What voids the permit exemption
Even a building under 10 m² loses its exemption the moment you add any of the following:
- Plumbing. A sink, toilet, shower or outdoor shower plumbed into the building means a permit, full stop. If you are planning a bunkie with a bathroom, budget for a permit and for your septic system.
- A second storey. A sleeping loft inside a single-storey building is usually fine. A true second floor is not.
- Attachment. Connecting the bunkie to the house or to a deck that is attached to the house can turn it into an addition.
- A wood stove. Installing a solid-fuel appliance normally needs its own permit, and your insurer will want a WETT-certified installation. See our guide on how to heat a bunkie.
- Heat, in some municipalities. As the Ottawa advisory shows, a heated building may fall outside the exemption.
No building permit does not mean no rules
The exemption covers the building permit only. Several other approvals still apply to a permit-exempt shed or bunkie:
- Zoning bylaw. Setbacks from lot lines, maximum height, maximum lot coverage, and the number of accessory buildings allowed. Many cottage-country bylaws also have specific “sleep cabin” rules that cap the floor area and ban kitchens.
- Conservation authority. If the lot is near a lake, river, wetland or floodplain, you may need a permit from the local conservation authority even for a small building.
- Septic setbacks. Do not place a building over or right next to the septic tank or leaching bed.
- Electrical. Any new wiring in Ontario needs an Electrical Safety Authority (ESA) permit, whatever the size of the building. Our guide to adding electricity to a bunkie explains the steps.
- Heritage, HOA or condo rules where they apply.
How to check with your municipality in 15 minutes
- Find your property’s zoning on your municipality’s online zoning map, or call the planning department.
- Ask the building department three questions: “Does a detached sleep cabin under 10 m² need a permit here?”, “Do you apply the 15 m² exemption to anything other than storage?” and “How do you measure gross area?”
- Ask planning for the accessory-building setbacks and the maximum height for your zone.
- If you are on the water, call the conservation authority for your watershed.
- Get the answers in writing (an email is fine) and keep them with your purchase records.
Choosing a bunkie size that keeps things simple
If you want to avoid a permit, the most reliable route is a detached bunkie under 10 m² with no plumbing. That still leaves room for a double bed and storage, or a set of bunks for the kids. Browse our cabins up to 108 sq. ft. (10 m²) and bunkie kits, and check the external dimensions on each listing.
If you need more space, a building in the 108 to 161 sq. ft. range is often worth the extra paperwork. A permit for a small accessory building is usually quick, and it means your bunkie is on record when you sell or insure the property.
For the national picture, read Do you need a permit for a bunkie in Canada? and our guide to the best bunkie foundation.
FAQ
What is the maximum shed size without a permit in Ontario?
15 m² (161 sq ft) gross area, provided the shed is one storey, detached, used only for storage and has no plumbing. Other small buildings are exempt up to 10 m² (108 sq ft) without plumbing.
Can I sleep in a 15 m² shed without a permit?
Not automatically. The 15 m² exemption is written for storage. Some municipalities accept personal use such as a studio or hobby room; others require a permit as soon as the building is used for sleeping. Ask your building department.
Does a sleeping loft count as a second storey?
A loft inside a single-storey building is generally not treated as a second storey, but very large lofts with full headroom can be. Check with your municipality if the loft is more than a sleeping platform.
Do I need a permit to put electricity in my bunkie?
Yes. Electrical work in Ontario needs an ESA permit and inspection regardless of the building’s size or whether it needed a building permit.
Is a bunkie with a bathroom allowed?
It can be, with a building permit and a septic system (or sewer connection) that can handle the extra fixtures. Many cottage-country zoning bylaws limit or ban bathrooms and kitchens in sleep cabins, so check zoning first.
