Secondary suites

A dwelling unit with a secondary suite must have at least one exit which leads directly outside. Subsection 9.9.9. of the Manitoba Building Code deals with the egress from dwelling units. Required entrance doors shall have a minimum width of 810 mm (2'-8"). An exit stairway shall have a minimum width of 860 mm (2'-10").

Where the suite does not contain a sprinkler, each bedroom shall have at least one window designed as a means of egress, should the required exit become obstructed. An egress window must have an unobstructed opening of 0.35 m² (3.8 ft²) and the minimum height or width of the opening shall be not less than 380 mm (1'-3"). Egress windows are to have either a casement or sliding operation. Where a window well serves an egress, it must project out from the wall at least 760 mm (2'-6").

The Manitoba Building Code requires a minimum 1.95 m (6'-5") floor-to-ceiling height for a secondary suite. Clear heights under beams can be reduced to 1.85 m (6'-1"), but door openings cannot be reduced to less than 1.89 m (6'-2 1/2") – where a lower ceiling height does not allow for a full height door.

A means of protection against the spread of smoke and fire from one dwelling unit to another is essential. Also, any common space, other ancillary spaces, or rooms containing heating equipment must be protected from the remainder of the building. This is achieved by providing a layer of 1/2" drywall on the underside of floor framing (ceiling) and on both sides of wall studs that separate the dwelling unit from the suite or common spaces.

New smoke alarms are to be installed in each dwelling unit and in ancillary/common spaces not within the dwelling units. They should be interconnected so that the activation of any one smoke alarm causes all smoke alarms in both dwelling units to sound. Carbon monoxide alarms are to be installed within 5 m (16'-5") of each bedroom door or inside each bedroom when a residential occupancy has an attached garage or contains a fuel-burning appliance. A carbon monoxide alarm shall also be installed within a service room that is not within the dwelling unit. The carbon monoxide alarm shall be interconnected so that the activation of any one alarm causes alarms in both dwelling units to sound.

The Sound Transmission Classification between units is required to be rated at a minimum of 43. Common walls and ceilings are required to have min. 1/2" drywall, resilient sound channels and batt insulation. Alternatively, any wall/ceiling assembly that meets STC 43 (as prescribed by the code) is also acceptable.

A secondary suite requires a dedicated heating system with controls, separate from the system serving the primary dwelling unit in the house. Air duct distribution systems cannot be interconnected between dwelling units. Where a separate forced air heating system is provided, a heat recovery system must be installed to provide for the exhaust of stale air from, and supply of fresh air into the suite. When no forced air heating system exists, incoming fresh air shall be supplied through a system of supply ducts to each bedroom, each story in the dwelling unit without a bedroom, and to the principal living area.