Window Wells, Covers & Stairwell Retaining in Calgary

The problem this solves

It is tempting to think of a window well as a trim piece around a basement window. It is really a small retaining wall, keeping a cut face of soil away from the foundation right where you least want soil pushing. That push is not the same everywhere. Sideways earth pressure increases the deeper you go, so the load near the bottom of a deep egress well is in a different league from the load just under the surface. A shallow well for a daylight window and a deep egress well are therefore two different products, not one product in two sizes. Wet clay behind the well makes the load heavier again, since water trapped in the backfill presses on the well in addition to the soil.

Drainage is the other half, and it is responsible for most of the damage you can actually see. A well is a pit dug right up against the house. If water has no exit, the well turns into a tank: rain off the roof, spring melt and runoff from the yard all collect in it, the gravel at the base clogs with silt, and standing water sits on the sill, the window and the foundation behind it. Caulking the well tight to the wall does not solve this; a sealed joint with no drain simply makes the tank deeper. When we look at a failed well, the cause is nearly always a drain that was never installed or one that slowly clogged.

Size is the third factor, and it is what turns a well from an upkeep issue into a code issue. The well must keep 760 mm clear of open space beyond the window sash when it is fully open. If the well is too shallow front to back, a window that would otherwise comply fails, because its own well gets in the way. Depth follows the same logic: a permanent ladder or steps is required deeper than 1.2 m, and those steps are not allowed to take up the clear space the well must provide. An inspector confirms whether a particular window and well combination passes.

What happens during the work

The drain is installed before the well. We dig until the foundation and the base of the future well are exposed, find the existing weeping tile or a rock sump and prove it actually carries water away instead of assuming it does, and then place drain rock and a drain at the bottom. Only after that is the well set, lined up with its window, levelled and fastened to the wall. Soil goes back in thin, compacted layers so the well never takes the weight of a large pile of loose fill in one go. The cover or grate goes on, steps are added if the depth requires them, and the surrounding grade is reshaped so water flows away from the house.

Owners are often surprised by how the time breaks down. Placing the well takes very little time; digging, connecting the drainage and backfilling are the real work. When we replace an old well, what we pull out usually explains the failure: a well packed with fine silt and no gravel below, or a thin corrugated liner backfilled with clay and pushed inward along one side, tells us exactly what the new one needs to do better. Plan on an open hole in the yard while we work, a pile of soil beside it, and a patch of grass or paving that gets lifted and put back afterward.

What shapes the design

Depth drives almost every other decision. A shallow well can be a light corrugated galvanized unit, but a deep one is resisting real sideways pressure and calls for a thicker gauge, precast concrete, or a poured and reinforced well connected to the foundation. Depth also decides whether fixed steps or a ladder are needed (required deeper than 1.2 m), and whether the well has to be made larger so those steps leave the 760 mm clear of projection untouched. After depth, the main factors are the type of soil and how well it drains, whether there is working weeping tile or a sump to connect to, the slope of the lot, and whether equipment can get to the wall.

Retaining walls for an entrance stairwell are a bigger undertaking still. The stairwell leading down to a walk-out or separate basement door is a permanent open excavation with walls on three sides and people walking through it every day, so it is engineered rather than pieced together: the wall system, its reinforcement, drainage at the foot of the stairs, and a connection to the foundation that does not trap water at the seam. When the height, the soil, or extra load from a driveway, fence or nearby building justifies it, an APEGA-licensed P.Eng. stamps the design and it goes in with the permit application. Choosing a well cover or grate is part of the design as well, not an add-on.

What is different about window wells & covers in Calgary

Every era of window well can be found somewhere in Calgary. Homes in pre-war neighbourhoods often have wells built long before anyone put a drainage bed under them, suburbs from the 1970s and 80s are full of thin galvanized wells nearing the end of their life, and the newest lake communities come with engineered lot grading plans that any new well must work with. Soil conditions shift just as much. The glaciolacustrine clay common in the north and east of the city keeps water pressed against foundations, and communities on the river flats can have a high water table sitting just below the base of a well.

That means most calls fall into one of three situations. A basement window has just been enlarged or added and needs a new well. An original well has rusted, bent or filled up and is now directing water against the foundation it was supposed to protect. Or a bedroom window was made bigger and the existing well no longer leaves enough clear space in front of the open sash, so the window fails because of the well and not the window. In all three cases the City of Calgary is the permitting authority, and in all three the answer depends on where the water ends up.