Secondary suite code requirements

The ceiling height within a secondary suite and above stairs must be no less than 1.95m (6’4¾”). Ceilings are permitted to be reduced below ductwork and beams to 1.85m (6’3/4”).

• Doors cannot be less than 1890mm (6’3/4”) in height.
• A utility room door (laundry or furnace room) cannot be less than 800mm (32”) wide.
• At least one bathroom per floor must have a door leading to all bathroom fixtures that is not less than 760mm (30”) wide.
• All doors leading from the exterior to the basement must be not less than 800mm (32”).
• Any doors separating a secondary suite and another dwelling, common space or the furnace room must have a solid core wood 45mm thick doors with a self-closing device.
• Doors must be tight fitting with no more than 3mm clearance on the sides and top and 6mm at the bottom.

Exiting and entry

• Stairs serving as an exit must be at least 860mm (34”) wide.
• Both the primary dwelling and a secondary suite must have at least one exit that leads directly to the outside.
• Both the primary dwelling and a secondary suite may share a common exit vestibule that is separated from both the primary dwelling and the secondary suite and has an exterior door.
• The exit door that leads to the exterior may be at grade or with an exterior staircase leading to grade.
• The exit door must swing on a vertical access. A sliding door cannot be used as the principal exit for either dwelling.

Protection of exits and stairs (in a dwelling that has only one exterior exit)

• The exit door must be protected from windows and doors located in the other dwelling or common space, when they are located within 3m (9’-10”) horizontally of the exit door and the adjacent wall is built at an angle less than 135°.
  
• A window or door that is not part of the same dwelling unit or common space, must be separated from the exit door and stairway by 5m (16’-5”) vertically and 3m (9’-10”) horizontally, or provided with protection.
• Windows or doors that are required to be protected must be removed or changed to glass block or wired glass in steel frames. Bedroom windows cannot be changed and cannot be within the clearances noted above because a bedroom window must maintain the required minimum opening requirements. See bedroom windows for more information.
• Stairs which are less than 600mm (24”) above or below grade and are not enclosed by guardrails or handrails do not require the 3m horizontal and 5m vertical clearances.
  
  

• An alternate method of protection is a roof constructed of solid materials such as wood, metal or concrete that covers the entire stair.

• Roof systems over proposed exterior exit stairs which are located within a required front, side or rear yard may not be allowed under the Airdrie Land Use Bylaw. Homeowners wishing to install a roof system for the protection of an entry are encouraged to contact Current Planning at 403.948.8832 or planning@airdrie.ca to confirm if it is allowable under the Land Use Bylaw.

• A secondary suite and the primary dwelling must be separated from each other and from any common/shared spaces such as a shared exit vestibule by a smoke tight barrier.
• Rooms containing gas-fired appliances including furnaces, hot water heating units and gas dryers must be separated from the rest of the house by a smoke tight barrier.
• A smoke tight barrier consists of minimum ½” drywall on both sides of common walls and on the underside of floor systems. See sound transmission for additional requirements.
• The smoke tight barrier is also required where there is a return air chase in the ceiling. A joist cavity cannot be used as a return air chase using conventional joist liner serving the secondary suite. The secondary suite return airs will need to be ducted or the joist cavity drywalled. See diagram in sound transmission.
• Sealing the drywall in a utility/furnace room can be difficult as there are many electrical, plumbing and ductwork penetrations which must all be sealed around.
• Homeowners in existing homes are encouraged to investigate the associated costs for providing a sealed ceiling in the service room with local drywall companies.

• Floors and walls that separate the primary dwelling unit, the secondary suite and any common spaces must be provided with a minimum sound transmission (STC).
• A ceiling assembly typically requires the installation of 6” of insulation along with resilient metal channels at 16” or 24” on centre, and ½” drywall on the ceiling.
• A wall assembly typically requires the stud cavities to be filled with insulation and resilient metal channels on one side of the wall at 16” of 24” on centre with 1/2” drywall on both sides of walls.
• The STC requirements apply to the entire floor area including joist cavities containing ducts and return air chases. If joist cavities cannot provide the required sound insulation above or below ducts and return airs, bulkheads may be required below to accommodate the required insulation.
• Alternately, to achieve the STC requirements you can use a tested assembly within the Building Code which has an STC of 43 or a separating assembly and adjoining construction, which together provide an ASTC rating of not less than 40.
• If a floor or wall assembly is utilized which does not meet the above prescriptive requirements, sound tests conducted by a qualified acoustic consultant may be provided to demonstrate compliance.
• Homeowners changing existing developed spaces are encouraged to investigate the associated costs for meeting the sound transmission requirements with local drywall companies.
  

• Every bedroom must have an openable window that provides egress when the window is in the open position.
• The minimum clear openable area of not less than 0.35m² (3.77 ft²) with no dimension less than 380mm (15”) is required.
• Bedroom egress windows must be able to be openable from the inside without the use of keys, tools or special knowledge and without the removal of sashes or hardware.
• Bedroom egress windows must be able to remain in an open position without the need for additional support.
• These requirements limit the style of windows that are acceptable for use as an egress window. Picture windows, hopper and many awning style windows are not acceptable as egress windows. Security bars are also likely not permitted.
  
  
• Egress windows opening into a window well require a minimum clearance of 760mm (30”) in front of the window.
• Egress windows below cantilevers shall have a minimum clearance of 760 mm (30”) between the underside of the projection and the top of the window well or adjacent grade.
• The cantilever should not project more than 610mm (24”) from the principal wall.
• Egress windows below decks are not permitted unless there is a minimum headroom clearance of 760mm (30”) between grade and the underside of the deck and the window opening is immediately adjacent to the edge of the deck above.
• All window wells must be drained to the footing level or another suitable location such as a dry well minimum 5m away from the building.

• Smoke alarms are required in every bedroom, every hallway serving a bedroom and on every storey.
• A smoke alarm is required in all common and ancillary spaces.
• A smoke alarm is required to be interconnected with all smoke alarms within the secondary suite and every smoke alarm in the primary dwelling so that activation of one smoke alarm activates all alarms.
• Every smoke alarm must be hardwired into an electrical circuit with a battery back-up.
• Carbon Monoxide (CO) alarms are required in every dwelling with a fuel burning appliance or an attached storage garage.
• CO alarms must be located within each bedroom or located within 5m of each bedroom.
• A CO alarm is also required in a shared utility room that has a fuel fired appliance (gas furnace, gas hot water tank or gas dryer).
• All CO alarms must be interconnected so the activation of any one CO alarm causes all CO alarms within the house, the secondary suite, and the common spaces to sound.

• A separate heating and ventilation system along with independent temperature control is required for secondary suites. No ductwork can be shared between the primary dwelling and the secondary suite or the common spaces.
• This is commonly done by installing a second furnace serving only the secondary suite. Another popular option is an alternate heat source (electric baseboard or boiler heat) along with a means to provide adequate ventilation such as a heat recovery ventilator (HRV).
• Common spaces such as exit vestibules cannot be heated or ventilated by the same appliance used for heating or ventilating one of the dwelling units.
• A common exit vestibule is not required to be provided with ventilation, but it must be provided with a heat source which can maintain a minimum temperature of 18°C, such as electric baseboard heating.
• As part of the permit application, heat loss calculations from a qualified contractor must be provided which show the room-by-room cfm requirements and proposed duct sizing. If you are using electric heat you must provide the wattage requirements for each room and the proposed base board heating sizes.
• HVAC work being completed for a secondary suite must be completed by a qualified HVAC contractor. A homeowner cannot do the HVAC work themselves.
• Homeowners are encouraged to investigate heating options for a secondary suite and any common spaces with local heating service companies to minimize costs.

Electrical work

• Electrical work being completed for a secondary suite must be completed by an electrical contractor. A homeowner cannot do the electrical work themselves.

Electrical service load

• An electrical service load calculation (pdf) must completed by a qualified contractor and submitted as part of the permit application to ensure the service demand for both dwelling units does not exceed the available load provided.
• Where a system is not sufficient, additional measures can be proposed to address the electrical system needs.

• Plumbing work being completed for a secondary suite must be completed by a plumbing contractor. A homeowner cannot do the plumbing work themselves.
• Secondary suites are considered as separate dwelling units as per the Plumbing Code because they operate under a single tenancy. Where an existing normally open backwater valve is installed, and it serves more than one dwelling unit, it may be necessary to install additional backwater protection.
• All fixtures located within the secondary suite (including mechanical room floor drain if it is located within the secondary suite) require separate backwater protection.
• Water distribution systems serving more than one dwelling require a shut-off valve installed on the water supply to each unit to ensure that, when the water supply to one suite is shut off, the water supply to the remainder of the building is not interrupted.

• Gas work being completed for a secondary suite must be completed by a gas contractor. A homeowner cannot do the gas work themselves.