Community Development
Building Services Division
50 Dickson Street, 3
rd
Floor
Cambridge, Ontario, N1R 5W8
Telephone: 519-623-1340 Fax: 519-622-6184
TTY: 519.623.6691
www.cambridge.ca
Building Permit Requirements for Creating an Additional Residential Unit
A building permit is required to create an additional residential unit within an existing dwelling or an
accessory structure. This guide explains the most common requirements for submitting a building permit
application for an Additional Residential Unit and is based on the 2012 Ontario Building Code Part 9
When applying for a building permit the following must be submitted:
1. Application Form for a permit to Construct or Demolish
(15 business day review period)
2. Permit fees paid for at permit submission, minimum $126.00:
• $0.47/sf for previously finished areas being modified and unfinished areas being finished
PLUS
• $250 rebate fee (refundable upon final sign-off)
3. Schedule 1: Designer Information form
completed by:
• A qualified designer, minimum “House” required (designer declaration on all drawings),
• The registered homeowner, or
• Architect or Engineer (form not required when all drawings are stamped),
4. Site plan or Survey (drawn to scale)
• Show the required parking spaces and all dimensions
• Show the location of existing/proposed buildings and all setbacks (if applicable)
5. Construction drawings (single line drawings not acceptable, drawn to scale):
• Existing floor plans (all floors):
o Window/door sizes & locations, room names, stair location, wall locations &
construction, etc (for all floors).
• Proposed floor plans:
o New wall construction, fire separations (new and existing), new windows and
doors, room names, plumbing locations for kitchen, bathrooms & laundry, ceiling
heights (overall, under beams and ducts), egress/exits, etc.
o Show accessory structure framing, plumbing, heating, etc. (if applicable)
• Elevations (applicable if adding egress windows/doors with glazing)
Community Development
Building Services Division
50 Dickson Street, 3
rd
Floor
Cambridge, Ontario, N1R 5W8
Telephone: 519-623-1340 Fax: 519-622-6184
TTY: 519.623.6691
www.cambridge.ca
General Zoning Requirements for Additional Units
Contact our planning department with any questions about the below at 519-623-1340 4602. The
City of Cambridge Zoning By-law
is also available for review on the City of Cambridge website.
1. Requirements:
a. Up to 2 Additional Residential Units (ARUs) are now permitted in RR1, RR2, R1, R2, R3, R4
zones.
i. Where 2 units are permitted up to 1 unit may be located in an accessory
structure
ii. No more than 1 unit may be located in a basement/cellar
b.
1 Additional Residential Unit is permitted in R5, R6, RD3, RD4, RD5, RM1, RM2, RM3,
RM4
c. A maximum of 2 bedrooms is permitted within the additional unit (any room with a door and
closet is deemed a bedroom).
d. The unit or units together may not exceed 40% of the total floor area of the principal dwelling
(including basement).
i. Where the basement exceeds 40% of the total floor area the whole basement
may be used for a single unit.
ii. Units in an accessory structure may not exceed 80 sq. m of floor area regardless
of the total area of the principal dwelling.
e. The principle dwelling and additional unit must be connected to municipal sewer and water
services of adequate size (upgrading may be required). If on private water and sewer, proof
must be provided to show that they are capable to accommodate the additional unit,
satisfactory to the City of Cambridge.
f. Min. 2-3 legal parking spaces on the property (tandem permitted)
i. Principal dwelling unit requires 1 space for the first 4 bedrooms, plus 1 for each
additional 2 (e.g. 4 bedrooms requires 1, 5 requires 2, 7 requires 3, etc).
ii. Additional units require 1 space per unit.
iii. Spaces required by additional units may be forward of the regulatory building
line, spaces required by the primary dwelling unit may not.
Other Requirements
An ESA (Electrical Safety Authority) permit is required when electrical work is being completed.
Community Development
Building Services Division
50 Dickson Street, 3
rd
Floor
Cambridge, Ontario, N1R 5W8
Telephone: 519-623-1340 Fax: 519-622-6184
TTY: 519.623.6691
www.cambridge.ca
Building Design Requirements
o
• All penetrations through fire separations are required to be fire stopped with an approved fire stop
device. Existing penetrations are acceptable in existing fire separations.
REQUIREMENTS
BUILDING CONDITION
A
Less than 5 years since occupancy
B
5 years or more since occupancy
FLOOR FIRE SEPARATION (continuous)
Permitted Floor Fire Resistance Rating (FRR)
30 min - for all common spaces AND when interconnected smoke alarms
are not provided between both suites
15 min - when interconnected smoke alarms are provided between both
suites
Permitted Floor Sound Rating (STC)
Not required
WALL FIRE SEPARATION (continuous)
Permitted Wall Fire Resistance Rating (FRR)
30 min
Permitted Door Fire Protection Rating (FPR)
(Note: door requires a self-closing device)
20 min
Permitted Wall Sound Rating (STC)
Not required
SUPPORTING STRUCTURE
Permitted Fire Resistance Rating (FRR) for load bearing
walls, beams, and columns
Same as Floor FRR
HVAC SYSTEMS
Duct type Smoke Detector
Must be installed in 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 & CARBON MONOXIDE ALARMS (general requirements only, additional requirements may apply)
Interconnection between dwelling units
May be required based on Floor FRR
(see above)
Required locations and general requirements
Smoke alarms are required on every floor level, in every bedroom, in
hallways serving a bedroom, and in all common areas. All smoke alarms
within a dwelling unit shall be interconnected and have a visual signaling
component (strobe light).
Carbon Monoxide alarms to be installed in hallways serving a bedroom.
MINIMUM WINDOW AREA
Living and Dining Rooms
10% of area served
5% of area served
Bedrooms and other Finished Rooms (except kitchens
and washrooms with electrical lighting)
5% of area served 2.5% of area served
CEILING HEIGHT (Minimum)
All Rooms
6’-11 over entire floor
6’-5” under beam/duct
6’-5” over all required room areas
and any location normally used as a
mean of egress
Community Development
Building Services Division
50 Dickson Street, 3
rd
Floor
Cambridge, Ontario, N1R 5W8
Telephone: 519-623-1340 Fax: 519-622-6184
TTY: 519.623.6691
www.cambridge.ca
Calculat
ing
Window Area:
Building Design Requirements
• Any doors between units must have a minimum 20 minute fire protection rating with a self-closing
device.
• Combined areas are where one room contains multiple room functions (i.e. open concept, studio
apartment, etc.)
• Each unit shall have access to common laundry facilities or have connections within each unit for the
connection of laundry appliances
Note: These design tips do not cover all of the requirements for Secondary Suites. The person taking
responsibility for the design should refer to the 2012 Ontario Building Code for a detailed listing of all
requirements. The most current Building Code is available at e-Laws - Ontario Building Code
.
•
Exiting to meet the requirements of the Ontario Building Code. If an exit is shared by
Window area required as per the Building Specific
Design Requirements must be calculated by taking
subtracting any non-glazing components
Accurate area calculations or manufacturer
specifications must be provided with your building
permit application.
Note: Shaded area represents glazing area
DOOR SIZES (Minimum)
Minimum Width
Minimum Height
Dwelling Unit Entrance or Utility Room
32”
78” or to match existing
ceiling height
Bedroom or Rooms not mentioned elsewhere
30”
Bathroom, Washroom, and Walk-in closets
24”
ROOM SIZES - Separate Spaces
Min. ft
2
ROOM SIZES - Combined
Min. ft
2
Living Room
145
Living Room (> 1 bedroom)
145
Dining Room
75
Living Room (1 bedroom)
118
Kitchen (> 1 bedroom)
45
Dining Room
35
Kitchen (1 Bedroom only)
40
Kitchen (> 1 bedroom)
45
Master Bedroom (with closet)
95
Kitchen (1 bedroom)
40
Master Bedroom (without closet)
105
Bedrooms
45
Other Bedroom (with closet)
65
Other Bedroom (without closet)
75
ROOM SIZES - Bachelor
Min.ft
2
Bathroom
Sufficient space for
fixtures
Living, Dining, Bedroom and
Kitchen
145
Community Development
Building Services Division
50 Dickson Street, 3
rd
Floor
Cambridge, Ontario, N1R 5W8
Telephone: 519-623-1340 Fax: 519-622-6184
TTY: 519.623.6691
www.cambridge.ca
both units, a larger egress window is required and interconnected smoke alarms are
required in every bedroom and common space throughout the entire house.
• An egress window is required in basement units containing a bedroom except for walk-
out basement conditions, where direct access to exterior is provided.
Fire Separations in Furnace Rooms:
Due to the difficulty of installing a continuous fire separation on the ceilings of furnace rooms
separation to be waived where the spaces are sprinklered.
Where a continuous horizontal fire separation is not achievable, sprinklering of the furnace room
ceiling is acceptable. The installation of sprinklers may not be feasible where a water service
into a home may not be adequately sized without updating the entirety of the system. The walls
around the furnace room are to be constructed as vertical fire separations.
Installation of a sprinkler head(s) in furnace room location
A single sprinkler loop installed by a qualified sprinkler installer may be installed in the furnace
room when a continuous fire separation cannot be achieved due to obstructions.
System Components:
• Piping materials include: copper (Type L) & cross-linked polyethylene pipe fittings (PEX)
certified to CAN/CSA-B137.5
• Listed residential sprinklers shall be used (manufacturer spec. sheets must be retained
on-site)
Design Requirements:
• Only residential full flow through installations are permitted
• An adequate water supply shall be confirmed for the demand (min. ¾” diameter service)
• No isolation valves permitted on any portion of the sprinkler service line upstream of the
sprinkler head
• Warning sign min. 200mm x 200mm (8”x8”) shall be installed adjacent to the main shut
off valve indicating that the domestic service is also used for a fire sprinkler system and
must not be left closed
• A floor drain is strongly recommended to be located in the vicinity of the sprinkler head
