A building permit is needed to construct buildings in Ontario.  People are sometimes surprised that this requirement doesn’t just apply to new home builds, but also to some renovations, open-air structures, and even septic systems. This post touches on some of the lesser-known situations where a building permit may be required.
- Renovations and Additions
In the Building Code Act, “construct” means to erect, install, extend, materially alter or repair a building. A permit is therefore required for additions and significant renovations.
Where an addition is not physically attached to a building, in some cases a permit may still be required if it functions as part of a building – in one case an outdoor gazebo kitchen was considered to be annexed to a nearby restaurant and therefore subject to the Building Code.  And even renovations to downsize a building can still require a building permit if the alterations are material.
Large docks can require a building permit, because a “building” includes structures over ten square metres with a floor, even if they have no walls or roof. 
- Small structures with plumbing
A “building” includes any structure with plumbing, i.e. sewer drainage or water supply. Structures with these systems require permits even if the structures are smaller than ten square metres.
- Installing a Tiny Home
A building permit is required to install a fabricated building, so a permit is required for tiny homes even if they were assembled or fabricated off-site.
- Large or Permanent Tents
Generally, a permit is only required for a tent (or a group of tents) larger than sixty square metres or less than 3 metres from another building.  However, “tent” means a temporary and portable shelter.  Courts and tribunals have found that permanent and unmovable fabric structures are not considered “tents” and require a building permit. 
- Septic Systems
A “sewage system” is also considered a building. A sewage system includes systems like chemical or incinerating toilets, greywater systems, cesspools, leaching beds, and sewage holding tanks. A building permit is needed to “construct” any of these systems – this includes installing, extending or materially altering them.
This is not an exhaustive list of all the cases where a permit may be needed. You can contact your local Chief Building Official or our Municipal Team for Building Code or Building Code Act inquiries.
 The Building Code Act, section 8(1). There is no single definition of “building” in the Act – a building includes: structures over ten square metres with a roof, floor or walls; buildings under ten square metres with plumbing; sewage systems; and other structures designated in the Building Code, Division A, Part 1, Section 22.214.171.124.
 2364899 Ontario Ltd. v. Bracebridge (Town), 2015 ONSC 6553.
 R. v. Black,  O.J. No. 3049.
 Division C, s. 126.96.36.199 of the Building Code.
 Demers v. Township of Killaloe-Hagarty-Richards, 2017 ONSC 4211 (“Demers”).
 Demers; Building Code Commission Ruling No. 05-01-1015.