Basement Bedroom Exit Window Requirements

The Ontario Building Code, Part 9, provides the requirements for an exit window for a bedroom in a basement. If there is a door on the same floor level that provides direct access to outside then an exit window is not required. Also a bedroom window is required to meet minium size requirements. The Ontario Building Code 9.7.2.3. Minimum Window Areas – states that the minimum glass area for a bedroom must be 5% of area served.

Basic Exit Window Requirements

The window must be openable from the inside without the use of tools or special knowledge.
It must provide an unobstructed opening with a minimum area of 0.35 sq. m. (3.77 sq. ft.) with no dimension less than 380 mm (15 inches).
There must be a 550 mm (22 inches) space of clearing in front of the window.
Where a window sash swings towards a window well, it must not do so in a way that would restrict escape in an emergency.
Window sill can not exceed 1,000 mm height from floor. (bench or step may be added to comply)

Common Exit Window Misconception

The most common mistake that people make is thinking that the Exit Window is required in every bedroom, when in fact the window only has to be on the same floor level. A basement bedroom is required to have a window which has a minimum area of 5 % of the area served. Also the unobstructed glass area of door or skylight is considered equivalent to that of a window.

9.9.10.1 Egress windows or doors for bedroom

(1) Except where a door on the same floor level as the bedroom provides direct access to the exterior, every floor level containing a bedroom in a suite shall be provided with at least one outside window that,

(a) is openable from the inside without the use of tools,

(b) provides an individual, unobstructed open portion having a minimum area of 0.35 m² with no dimension less than 380 mm, and

(2) Except for basement areas, the window required in Sentence (1) shall have a maximum sill height of 1 000 mm above the floor.

(3) When sliding windows are used, the minimum dimension described in Sentence (1) shall apply to the openable portion of the window.

(4) Where the sleeping area within a live/work unit is on a mezzanine with no obstructions more than 1 070 mm above the floor, the window required in Sentence (1) may be provided on the main level of the live/work unit provided the mezzanine is not more than 25% of the area of the live/work unit or 20 m², whichever is less, and an unobstructed direct path of travel is provided from the mezzanine to this window.

(5) Where a window required in Sentence (1) opens into a window well, a clearance of not less than 550 mm shall be provided in front of the window.

(6) Where the sash of a window referred to in Sentence (5) swings towards the window well, the operation of the sash shall not reduce the clearance in a manner that would restrict escape in an emergency.

The Ontario Building Code 9.7.2.3. Minimum Window Areas – states that the minimum glass area for a bedroom must be 5% of area served.

National Building Code for Basement Exit Window

The National Building Code of Canada (NBCC), on which the Provincial Codes are based, has very clear requirements as it relates to bedroom windows and how the bedroom window serves three distinct purposes in the home:

Light (at least five per cent of the floor area served)
Ventilation (at least 0.28m² or 3 ft² or an adequate year-round mechanical ventilation)
Emergency Escape: An Emergency Escape requires that each bedroom must have a door that leads directly to the exterior of the building or have a properly-sized egress window that can be opened from the inside without the use of keys, tools, hardware or special knowledge (unless this bedroom has a sprinkler system installed).

9.9.10.1. Egress windows or doors for Bedrooms

(a) is openable from the inside without the use of tools,

(b) provides an individual, unobstructed open portion having a minimum area of 0.35 m² with no dimension less than 380 mm, and

(2) Except for basement areas, the window required in Sentence (1) shall have a maximum sill height of 1 000 mm above the floor.

(3) When sliding windows are used, the minimum dimension described in Sentence (1) shall apply to the openable portion of the window.

(5) Where a window required in Sentence (1) opens into a window well, a clearance of not less than 550 mm shall be provided in front of the window.

1997 Ontario Building Code 9.7.1.3. Bedroom Windows

NOTE: This article has been replaced by 9.9.10.1. Egress windows or doors for Bedrooms

(a) is openable from the inside without the use of tools,

(b) provides an individual, unobstructed open portion having a minimum area of 0.35 m² with no dimension less than 380 mm, and

Note: The National Building Code covers all of Canada. Provinces and Municipalities have the authority to add more restrictive measures to suit to their needs but can not lessen any of the requirements of the authority above them.

Fire Code Requirements

Note: You have to comply to both the Ontario Building Code and Fire Protection and Prevention Act, when appliacable.

Requirements for means of escape

9.8.3.1. Each dwelling unit shall be provided with a means of escape conforming to Article 9.8.3.2., 9.8.3.3., 9.8.3.4. or 9.8.3.5.

One means of escape

9.8.3.2. (1) Each dwelling unit shall be served by at least one means of escape consisting of a door that

(a) serves only that dwelling unit,

(b) opens directly to the exterior from that dwelling unit, and

9.8.3.3. (1) Each dwelling unit shall have direct access to at least one means of escape that may be shared if

(a) the means of escape is separated from the remainder of the building by a fire separation having a 30 min fire-resistance rating,

(b) the flame-spread rating of interior wall and ceiling finishes within the means of escape does not exceed 150, and

(c) the means of escape does not involve entering another dwelling unit or other occupancy and leads directly to the exterior with direct access to ground level.

(2) Where a means of escape provided by Sentence (1) serves a dwelling unit situated entirely on the third storey, the detached house, semi-detached house or row house shall be equipped with interconnected smoke alarms conforming to Article 9.8.4.1.

Two means of escape

9.8.3.4. (1) Each dwelling unit shall be served by at least two means of escape arranged in such a manner that

(a) one means of escape shall be through a door which may lead through another dwelling unit, and

(b) the second means of escape shall be through a window if

(i) the window conforms to Sentence (2) or (3), and

(ii) the detached house, semi-detached house or row house is equipped with interconnected smoke alarms conforming to Article 9.8.4.1.

(2) A window may serve as a second means of escape if

(a) the sill is not more than 1 m above or below the adjacent ground level,

(b) the window can be opened from the inside without the use of tools,

(c) the window has an individual, unobstructed open portion having a minimum area of 0.38 m² with no dimension less than 460 mm,

(d) the sill height does not exceed 900 mm above the floor or fixed steps,

(e) where the window has a window-well, a clearance of at least 1 m is provided in the window-well in front of the window, and

(f) where the window has a window-well, the window opens into the dwelling unit and does not interfere with escape.

(3) A window may serve as a second means of escape if

(a) the window is of a casement type,

(b) the window is not less than 1060 mm high and 560 mm wide,

(d) the sill of the window is not less than 1 m and not more than 5 m above the adjacent ground level.

The Wasaga Beach Home Inspector is a Certified Building Code Official with the Ontario Building Officials Association. Roger is also a Certfied Master Inspector who has inspected over 9,000 Residiential Properties.