Question Box: What Is The Legal Size Of A Basement Bedroom Window?

A common question from clients when viewing a basement bedroom: “Is that a legal size window?”

Below are some of the bylaw, code requirements and considerations for basement development for the City of Calgary:

  • For bedrooms, provide an unobstructed opening of NOT less than 0.35 m² (3.8ft²) in area with no dimension less than 380 mm (15”).
  • This window shall be openable from the inside without the use of tools or special knowledge. Normally, only slider and casement type windows meet this requirement.

Does the dimension and area given above refer to the size of the entire window opening or the size of the moveable panel?

The key word is “unobstructed.” The intent of this requirement is to provide an alternative means of escape from the bedroom in case of an emergency. Therefore any obstructions which cannot be easily and safely removed is not acceptable within the area dimensions.   Please see picture below for example:

Source: City of Calgary

The minimum dimension requirement is waived where a bedroom door provides direct access  to the exterior.

Where a window with the minimum dimension is required and that window opens into a windowwell, a clearance of at least 760mm shall be provided in front of the window.

Where the sash swings towards the window-well, the operation of the sash should not reduce the clearance in a manner that restricts escape
in an emergency.

For current information and more details, please visit the City of Calgary website.

4 responses to “Question Box: What Is The Legal Size Of A Basement Bedroom Window?

  1. Can you confirm minimum area for basement bedroom window opening is 3.8 square feet.
    So if my math is correct a 15″ tall sliding window needs to be over 6 feet ??
    This would give a 3 foot wide opening when sliding. 3×1.25 (15 inches)= 3.75 square feet.
    I haven’t seen many basement bedrooms six feet wide???

    Am I missing something or is my math correct?


    Please see the City of Calgary egress window guidelines for more info. Note 15″ was the minimum, and there are also casement type windows.
    -Mike Fotiou

  2. Glenn Batongbakal

    I have a window opening with the height of 15.5 inch the problem is the window frame is lessen the required minimum 15 inch. But is it posible if i used a fixed window with a slim type trim and just break glass window incase of fire?

  3. Ross your math is correct, however if you make the height 24″ the width now becomes about 4ft and yes there are Windows of this size!!!!

  4. I’m about to get into a basement renovation, and am curious about window requirements. What if the basement is a walkout type? The Basement door opens outward. does this change the window size requirement?

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