If you are finishing a basement in Calgary and putting a bedroom down there, the window in that bedroom has to be an egress window — big enough for someone to climb out of, and for a firefighter in gear to climb in. If that window sits in a window well, the well becomes part of the equation. Here is what the code asks for, and what it means for the well you order.

The three numbers that matter

Under the National Building Code – Alberta Edition (Article 9.9.10.1), a bedroom egress window must have:

• At least 0.35 m² (3.77 sq ft) of unobstructed openable area when fully open.
• No single dimension smaller than 380 mm (15″) — so a long letterbox slot does not qualify no matter how much area it adds up to.
• It must open from the inside without keys, tools or special knowledge, and without removing the sash or hardware.

And the one that catches people out

Where that window opens into a window well, the code requires at least 760 mm (30″) of clear space in front of the window. Not 760 mm from the foundation wall — 760 mm of space a person can actually use. If the sash swings outward into the well, you measure from the open sash, and the swing eats into your clearance.

This is the single most common reason a basement bedroom fails inspection with a brand new window installed. The window is fine. The well is too shallow.

What that means when you order a well

Projection is the second number in a well size (width × projection × height). For an egress window you want a 30″ projection, which gives you the 760 mm the code asks for. A 12″, 16″, 18″ or 22″ well is a perfectly good well — for a window nobody has to escape through.

We stock 30″ projection wells in widths from 48″ to 78″ and heights up to 42″, in galvanized steel and gloss black powder coat. If you are not sure which size suits your opening, our sizing guide walks through measuring.

A few other things inspectors look at

• Ladder or steps for deep wells — if the well is deep, you need a way to climb out of it.
• Covers must be openable from inside the well without tools. A screwed-down cover on an egress well is a fail. See choosing a cover.
• Drainage — a well that fills with water is a hazard as well as a nuisance. See water in your window well.

Check before you build

Code editions change and municipalities interpret them. Before you cut concrete, confirm the current requirement with the City of Calgary (or your municipality) and your permit — especially if you are creating a legal secondary suite, where the rules are stricter again. Treat this article as orientation, not as a permit.

Questions about which well size clears egress for your opening? Call (403) 972-0988 or email info@windowwellsandcover.ca.