Permits in Sarnia
When a backyard shed, deck, or fence needs a building permit in Sarnia, Ontario, with the size cut-offs, coverage level, and source link.
Coverage
Municipal rule
Shed
A building permit is required for accessory structures larger than 15 m2 (161 sq ft); smaller detached storage structures may be exempt if they have no plumbing, subject to zoning setbacks.
Deck
Decks more than 2 ft above grade require a building permit.
Fence
Fences do not require a building permit, but permitted fence heights include 2 ft, 2 ft; pool enclosures require a permit.
The provincial baseline
Under the Ontario Building Code, a detached one-storey storage shed of 15 square metres (about 160 square feet) or less, with no plumbing, does not need a building permit. Anything larger, with plumbing, or attached to another building does. Zoning rules (setbacks, height, lot coverage) always apply even when no building permit is needed.
Sarnia permit questions
Do I need a permit to build a shed in Sarnia?
A building permit is required for accessory structures larger than 15 m2 (161 sq ft); smaller detached storage structures may be exempt if they have no plumbing, subject to zoning setbacks. Source: Sarnia building department, last checked 2026-07-03.
Do I need a permit for a deck in Sarnia?
Decks more than 2 ft above grade require a building permit.
Do I need a permit for a fence in Sarnia?
Fences do not require a building permit, but permitted fence heights include 2 ft, 2 ft; pool enclosures require a permit.
Source
From Sarnia building department, last checked 2026-07-03. Deck detail: Listed below are some typical projects that do require a building permit: Constructing a new building Any addition to an existing building A detached building over 10 m2 (108 ft2) (Note: See exemption
This is a plain-language explainer, not legal or professional advice, and not the bylaw itself. Rules change and vary by zone within a city. Always confirm with your municipality's building department and the linked official page before you build. Decks and sheds near a conservation authority's regulated area may need a separate permit.
Other municipalities: Brooke-Alvinston, Dawn-Euphemia, Enniskillen, Lambton County. Or see every municipality.