As a Home Inspector, I frequently find cracks in the foundation at the lower corners of basement window openings. They occur there so often because it’s a weak point in the wall. The depth of the concrete in the window opening is less than the full height of the foundation wall surrounding it. When pressure from uneven settling or heaving acts on the wall, the wall in the window well cracks first. Does this mean that if we didn’t have any basement windows that we wouldn’t have any cracks? Not necessarily. If the pressure is great enough the wall will eventually crack somewhere. Besides basement windows have their virtues.
So now that we have accepted cracks at basement windows as a fact of modern living, why do we worry so much about them? Any crack is a potential entry point for water. Cracks within the confines of a window-well are in what amounts to a catch-basin for water. If water pressure builds up against a cracked basement wall, sooner or later that water is coming through to damage your basement renovations and possessions.
Modern basements should be built with a plastic membrane on the outside of the foundation to feed water down to the footing. From there it should run away through the perforated drain pipe installed at that level. All too often these components are missing or defective in older houses. Occasionally relatively new homes have these problems as well. What matters is that the homeowner gets to the bottom of the problem before the damage starts. And the best way to get to the bottom of the problem is for a foundation repair contractor to start digging.
Here we see the work the contractor has already done. 
The area around the crack has been excavated and the crack has been filled and covered with tar or an adhesive rubber membrane to seal it. Next a harder plastic sheeting that has a waffle-like texture is attached to the wall with fasteners shot into the concrete. The dimpled pattern will encourage water to percolate down to the footing more easily. You can see the new piece of perforated pipe that has been joined to the weeping tile at the footing.
Gravel is used as fill because it is porous and allows water to flow to the footing as well. The hole is filled with gravel and a galvanized window well is attached to the wall. Dirt fill is replaced around the window well and the grade is finished to slope away from the foundation wall. Finally the a cap is placed on the drain to lessen the likelihood of it becoming blocked with debris. All that remains to be done is to install some sod and enjoy a drier basement.
Note that multiple techniques have been used in combination to resolve this problem.
The wall was made as impermeable as possible. A platon membrane (the waffle), porous fill and a weeping tile has been installed to help remove whatever water arrives outside the wall. And finally, the grade has been sloped away from the wall to run water away. In combination they add up to the best solution to a crack that allows water into a basement. Because of all the work, the bill can add up to a hefty figure as well. All the more reason to make sure you get a good foundation repair contractor.
Photos courtesy of AboveWater Foundation Waterproofing & Restoration Services Inc.
Author: Rob Cornish is a Home Inspector in Ottawa, Canada. © 2013 HomeXam Inc.
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