Window wells are sized by three numbers, always in the same order: width × projection × height. Get those three right and installation is straightforward. Get one wrong and you are either re-excavating or living with a well that holds water. Here is how to measure each one.

1. Width

Measure the full width of the window opening, including the frame, then add clearance on both sides. As a rule of thumb you want the well to be 4 to 6 inches wider than the window so the side flanges land on solid foundation wall rather than on the window frame. A 32″ window is usually happiest in a 36″ well.

If you have two windows close together, measure from the outside edge of one to the outside edge of the other and treat it as a single opening — a 78″ well is often cheaper and better looking than two separate wells crowding each other.

2. Projection (depth out from the wall)

Projection is how far the well stands out from the foundation. This is the number most people get wrong.

• 12″ – 16″ — fine for a fixed or hopper basement window that nobody needs to climb through.
• 18″ – 22″ — comfortable for cleaning, and gives a casement sash room to swing.
• 30″ — what you need if the window is a bedroom egress window. Alberta requires 760 mm (30″) of clear space in front of the opening, so a shallower well will not pass. We cover this in detail in our Alberta egress requirements guide.

If the window swings outward into the well, measure the clearance from the open sash, not from the wall.

3. Height

Measure from finished grade down to a point roughly 2 to 4 inches below the window sill. You want the well to sit lower than the sill so that gravel and drainage live below the window, not against it. Then add a little so the top rim finishes at or just above grade — that lip is what stops soil and mulch washing in.

Common heights are 12″, 22″, 30″, 36″ and 42″. Deeper wells need a deeper gravel bed underneath, so plan the excavation before you order.

Sizes we stock

We roll wells in Calgary in widths from 36″ to 78″, projections from 12″ to 30″, and heights from 12″ to 42″. Stock sizes ship in 1–2 business days in G-90 galvanized steel, or in gloss black powder coat if you want it to disappear against dark siding.

What if nothing fits?

Older Calgary homes rarely have tidy openings. We cut, roll and rivet in our own shop, so a one-off size is a normal order rather than a special favour. Send your three measurements to info@windowwellsandcover.ca or call (403) 972-0988 and we will quote it.

Measuring tip: measure twice, at both ends of the opening. Foundation walls are rarely as square as they look.