Secondary Suites Guide - Obtaining Your Building Permit

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This building permit guide for secondary suites is intended to familiarize homeowners and their contactors with general requirements set out by the Ontario Building Code, and applicable law to help assist in obtaining a building permit for construction of new or conformity of existing secondary suite. 

Sections below outline general submission requirements such as types of documents and drawings necessary for review of a secondary suite construction, as well as, comprehensive requirements applicable to the construction of living spaces and safety requirements such as fire prevention.

Submission Requirements

  1. Completed Building Permit Application Form
  2. Two (2) sets of drawings/plans:
    • Drawn to scale and printed in ink
    • Fully dimensioned either in metric or imperial, but not in combination
    • Must include:
      • Site Plan
      • Existing Floor Layouts
      • Proposed Floor Layouts
      • Cross Sections and Wall/Ceiling/Fire Separation Construction Details
      • Elevations showing Secondary Suite Entrance and Egress Window
      • HVAC and mechanical drawings

Homeowners are permitted to prepare plans however the City of Peterborough recommends that drawings be prepared by a professional such as an engineer, architect, or a designer with a Building Code Identification Number (BCIN)

Construction & Safety Requirements

Building Code Requirements by Building Type
RequirementsDwellings in existence for less than 5 yearsDwellings in existence  for 5 years or olderDwellings in existence for 5 years or older with a finished basement
Floor Fire Separation (continuous) - Permitted Floor Fire Resistance Rating (FRR) 45 min 30 min 15 min with requirements
Permitted Floor Sound Rating  50 STC 50 STC Existing may be permitted
Permitted Wall Fire Resistance Rating (FRR) 45 min 30 min 30 min
Permitted Door Fire Protection Rating (FPR) (Note: Door requires a self-closing device) 20 min 20 min 20 min
Permitted Fire Resistance Rating (FRR) for load bearing walls, beams and columns in Supporting Structure 45 min 30 min 15 min with requirements
HVAC Systems - Duct type Smoke Detector Must be installed in supply or return air duct system and will completely turn off fuel and electrical supply to the heating system upon activation if existing furnace serves both dwelling units. Must be installed in supply or return air duct system and will completely turn off fuel and electrical supply to the heating system upon activation if existing furnace serves both dwelling units. Must be installed in supply or return air duct system and will completely turn off fuel and electrical supply to the heating system upon activation if existing furnace serves both dwelling units.
Smoke Alarms (general requirements only, additional requirements may apply)
Applies to 		 Only the new secondary suite Only the new secondary suite Both main unit and secondary suite
Smoke Alarms Interconnection between dwelling units Not required Not required Required
Required locations and general requirements Smoke alarms are required on every floor level, in every bedroom and in hallways serving bedrooms. All smoke alarms within each dwelling unit shall be interconnected and have a visual signalling component (strobe light) and include battery back up. Smoke alarms are required on every floor level, in every bedroom and in hallways serving bedrooms. All smoke alarms within each dwelling unit shall be interconnected and have a visual signalling component (strobe light) and include battery back up. Smoke alarms are required on every floor level, in every bedroom and in hallways serving bedrooms. All smoke alarms within each dwelling unit shall be interconnected and have a visual signalling component (strobe light) and include battery back up.
Natural Light in Living and Dining Rooms 10% of area served 5% of area served 5% of area served
Natural Light in Bedrooms and other Finished Rooms 5% of area served 2.5% of area served 2.5% of area served
Ceiling Height - All rooms 6'11 (2.1 m) over entire floor 6'5 (2.0m) under beam/duct 6'5 (2.0 m) over all required room areas and any location normally used as a means of egress 6'5 (2.0 m) over all required room areas and any location normally used as a means of egress

Table Note: The date of existence of a house is the date after the house permit has been issued, work has commenced and the first inspection has taken place. 

General Design Requirements

  • Carbon Monoxide alarms are required adjacent to each sleeping area
  • Each unit shall have access to common laundry facilities or have connections within each unit for the connection of laundry appliances
  • Minimum required dwelling unit size is 30 m2 and meet minimum room sizes as per Ontario Building Code requirements

Note: This design advice does not cover all requirements for secondary suites.  It is the designer’s responsibility to ensure compliance with the current Ontario Building Code.  A copy of the Ontario Building Code (Ontario Regulation 332/12 made under the Building Code Act, 1992) is available online through the e-Laws website.

Minimum Doorway Requirements
Door Connections Minimum Width (inches)Minimum Width (cm)Minimum HeightMinimum Height (cm)
Dwelling Unit Entrance or Utility Room 32" 81 78" 198
Bedroom or Rooms not mentioned elsewhere 30" 76 78" 198
Bathroom, Washroom and walk-in Closets 24" 61 78" 198
Minimum Space Size by Room Type for Separate Spaces
Room Sizes - Separate SpacesMinimum Area (ft²)Minimum Area (m²)
Living Room 145 13.5
Dining Room 75 7.0
Kitchen (>1 bedroom) 45 4.2
Kitchen (1 bedroom only) 40 3.7
Master bedroom (with closet) 95 8.8
Master bedroom (without closet) 105 9.8
Other Bedroom (with closet) 65 6.0
Other Bedroom (without closet) 75 7.0
Bathroom  Sufficient space for fixtures Sufficient space for fixtures
Minimum Space Size by Room Type for Combined Spaces
Room Sizes - CombinedMinimum Area (ft²)Minimum Area (m²)
Living room (>1 bedroom) 145 13.5
Living Room (1 bedroom) 118 11.0
Dining Room 35 3.3
Kitchen(>1 bedroom) 45 4.2
Kitchen (1 bedroom) 40 3.7
Bedrooms 45 4.2
Minimum Space Size by Room Type for Bachelor Spaces
Room sizes - BachelorMinimum Area (ft²)Minimum Area (m²)
Living, Dining, Bedroom and Kitchen 145 13.5

Building Permit Requirements: Sample Site Plan

Sample Site Plan for Secondary Suite

General Design Requirements

Key Sections – Ontario Building Code
Ontario Building Code: Key Sections to ReferenceSection Title
9.1 Fire Protection
9.11 Sound Transmission
9.31 Plumbing Facilities
9.32 Ventilation
9.33 Heating and Air Conditioning
9.34 Electrical Facilities
9.5 Design of Areas, Spaces and Doorways
9.8 Stairs, Ramps, Handrails and Guards
9.9 Means of Egress

Disclaimer: The design examples, including sample drawings, in this guide are not advice nor do they address all the requirements for legally establishing a secondary suite. It is each property owner’s responsibility to ensure compliance with all current applicable law, including the Ontario Building Code, the City’s Comprehensive Zoning By-law and any other provisions or regulations applicable to secondary suites. A copy of the Ontario Building Code (Ontario Regulation 332/12 made under the Building Code Act, 1992) is available online through the e-Laws website.