The short answer
A window well is a small retaining wall that keeps soil and water away from a basement window. It needs to sit below the window, drain at the bottom, and be fixed tight to the foundation so soil and water can't get in behind it.
On this page
How deep should window wells go?
The bottom of the well should sit below the bottom of the window frame. That leaves room for a layer of drain rock under the sill, so rain that falls into the well soaks away before it can reach the glass.
The well should also stand a little above the finished grade around it. That keeps surface water running across the lawn from pouring straight in. How far down you dig depends on how deep the window sits and where the drain will run.
Should window wells be filled with gravel?
The bottom should be. A layer of clean drain rock lets water drop through to the drain below instead of pooling against the window. Soil or bark mulch holds water and clogs the drain, so neither belongs in the bottom of a well.
Fill only the bottom, though. The well needs open space between the rock and the window so light gets in, and so a bedroom window can still be used as a way out.
Where does a window well drain go?
Usually down to the perimeter drain tile that runs around the footing of the house. A pipe runs from the bottom of the well down through the drain rock to the tile, and the tile carries the water away.
On older houses the drain tile may be clogged or missing, and a well that holds water after rain is often the first sign. In that case the well can't drain properly until the tile below it does.
How can I seal the gap between a window well and the foundation?
Metal and plastic wells bolt to the foundation wall, and the joint is sealed so soil can't wash in behind. If a gap has opened up, the well has usually settled or been pushed by the soil, and sealant alone won't hold it for long. Pull back the soil, refasten the well and then seal it.
A poured concrete well is formed against the foundation and built as a small wall with its own base. It fits odd sizes and deep basement windows, and it doesn't flex the way thin metal does when wet soil pushes on it.
How long do metal window wells last?
Galvanized steel wells rust over time, especially where the soil stays wet against them, which is most of the year in the Lower Mainland. Rust usually starts at the bottom edge and at the bolts.
Plastic wells don't rust but can bow under soil pressure. Poured concrete takes more work to build and lasts the longest. If you're replacing a failed well anyway, it's worth comparing all three for your window.
What does the building code say about window wells?
If the window is a bedroom exit window, the well in front of it has to leave enough clear space for someone to climb out. The size rules are set by the building code and checked by your city, so confirm them with your building department before you build.
A window that's there only for light has fewer limits, but it still needs to drain. If you're adding a basement suite, plan the exit windows and wells early, because the well size can change the excavation.
Not sure what your window needs? Send a photo of the window and the ground outside it with the booking form on this page. John will tell you what the well needs.
The bottom line
A window well is a small retaining wall that keeps soil and water away from a basement window. It needs to sit below the window, drain at the bottom, and be fixed tight to the foundation so soil and water can't get in behind it.
More questions
What do you put in the bottom of a window well?
Clean drain rock over the drain. Keep soil, mulch and leaves out, because they hold water and clog the drain.
Should window wells be covered?
A cover keeps leaves, snow and rain out and keeps people and pets from falling in. On a bedroom exit window the cover must open easily from inside, so check with your city before you fit one.
Which is better, plastic or metal window wells?
Metal is stiffer but rusts in wet soil. Plastic doesn't rust but can bow, and a poured concrete well avoids both.
Are window wells a good idea?
For any basement window at or below grade, yes. Without one, soil and water sit against the window and leak in.
Rules differ by city. Check yours with the source links above, or ask us at the site visit.