Egress Window Well Requirements

Check the window and the well together

The window’s clear-opening area and the well’s outside clearance are separate checks. A large well does not increase a small window’s usable opening, and a large window does not fix a restricted escape path. Use the clear-opening geometry checker alongside the City’s well guidance, then confirm the complete design with your permit authority.

If the well holds water, investigate the drainage and surface-grading questions before replacing the window alone. You can include safe outside photos in a free preliminary project review; do not enter a flooded or unstable well.

The clearance, and the detail that catches people out

760 millimetres is straightforward enough as a number. The part that is easy to miss is when it has to exist. The City is explicit that when the window is in the open position, minimum clearance of 760 millimetres must be provided outside the window so that egress is not restricted.

That matters because of how basement windows open. A casement or awning window swings outward into the well. If the well measures exactly 760 millimetres from the wall to its back edge, and the sash then swings 300 millimetres into that space, what a person actually has to climb through and stand in is not 760 millimetres. The measurement is of the usable space, not the excavation.

Covers

Covers are useful — they keep debris, rain, snow and the occasional animal out of the well. They are also, if done badly, the thing that turns an escape route into a trap. The City sets three conditions:

• Strong enough to support foot traffic. Somebody will eventually stand on it.
• Openable from the inside without keys, tools or special knowledge. The same principle that governs the window itself. A cover that is bolted, padlocked or screwed down defeats the window underneath it.
• No opening greater than 13 mm in one direction. Which rules out open-mesh grates with wide spacing.

Snow

The City raises snow accumulation directly: particular attention has to be paid to windows at or below grade opening into a well, and the accumulation of snow in the well should be considered to allow the occupant access.

This is not a footnote in Edmonton. A well positioned where snow drifts, or one that collects everything shovelled off an adjacent walk, can be full at exactly the point in the year when a basement bedroom most needs its second way out. Where the well sits, how it is covered, and whether it gets cleared are all part of whether the window works.

Drainage

The egress requirement is about escape rather than water, so drainage is not what the clearance rule is aimed at. But a well is a hole in the ground beside a foundation, and what happens to water that lands in it is a real question with real consequences for the wall behind it.

A well with no route out for water will hold whatever arrives — rain, meltwater, whatever runs off the grade above. In Edmonton that water then freezes and thaws repeatedly. Whether the answer for a given site is a drain tied into the perimeter system or a deep free-draining base is site-specific, but it should be decided rather than left out. More on drainage and Edmonton winters.

What to check on an existing well

• Measure from the foundation wall to the back of the well — is it at least 760 mm?
• Open the window fully. Measure what is left.
• Is the base of the well below the window sill, or level with it?
• Is there standing water, silt, or a tide line showing where water has sat?
• If there is a cover, can you open it from inside the well without a tool?
• Where does snow end up in February?