Additional Residential Units Guide: Obtaining Your Building Permit

Submission Requirements

1. Completed Building Permit Application Form – generated in the portal to be signed.

2. Drawings/plans drawn to scale and fully dimensioned either in metric or imperial but not in combination. Drawings must include:
   • Site Plan
   • Existing Floor Layouts
   • Proposed Floor Layouts
   • Cross Sections and Wall/Ceiling/Fire Separation Construction Details
   • Elevations showing ARU Entrance and Egress Window
   • HVAC and mechanical drawings

The site plan and lot grading and drainage plan must clearly indicate an unobstructed and maintained path for firefighting access that meets the requirements of Section 6.33.3(d) of the City’s Zoning By-law. This must be provided to and approved by Engineering Development before permit may be granted. 

If constructing an ARU in an ancillary/accessory building, proof that the existing sanitary and domestic cold water (DCW) services will adequately support the increased load. An engineer possessing PEO designation will be required to verify/design the plumbing systems to ensure they meet the OBC. Only one sanitary and DCW service from the City services is permitted per property.

Drawings are to be prepared by a professional such as an engineer, architect, or a designer with a Building Code Identification Number (BCIN)1,2

1If there is a Principal Unit with one additional residential unit within the dwelling, the homeowner may be permitted to prepare the drawings. It is recommended that the owner engage the services a BCIN designer qualified with a minimum House

2If there are a total of 3 dwelling units within the dwelling, a designer with minimum qualifications in Small Buildings is required.

Construction & Safety Requirements

The following tables are a reference for one proposed additional residential unit in the dwelling with a Principal Unit and does not address all OBC requirements. Where a second additional residential unit is proposed in the dwelling (total of 3 dwelling units), please consult a BCIN designer qualified in Small Buildings.

Building Code Requirements by Building Type

Requirements	Dwellings in existence for less than 5 years	Dwellings in existence  for 5 years or older	Dwellings 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 ARU	Only the new ARU	Both Principal Unit and ARU
Smoke Alarms Interconnection between dwelling units	Not required	May be required	May be 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 (1950 mm) over all required room areas and any location normally used as a means of egress	6'5 (1950 mm) over all required room areas and any location normally used as a means of egress

Table Note: The date of existence of a dwelling is the date after the dwelling 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 ARUs.  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 Height	Minimum 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 Spaces	Minimum 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 - Combined	Minimum 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 - Bachelor	Minimum Area (ft²)	Minimum Area (m²)
Living, Dining, Bedroom and Kitchen	145	13.5

Building Permit Requirements: Sample Site Plan

General Design Requirements

Key Sections – Ontario Building Code

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

Disclaimer: The design examples, including sample drawings, in this guide are not advice nor do they address all the requirements for legally establishing an ARU. 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 ARUs. 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.

• A copy of the City’s Comprehensive Zoning By-law is available online through City of Peterborough’s website.