What the code asks for
The residential code used across our area calls for a clear opening of at least 5.7 square feet, no less than 24 inches high and 20 inches wide, with the sill no more than 44 inches above the floor. Outside, the window well needs at least nine square feet of floor area and a 36-inch projection, and if the well is deeper than 44 inches it needs a permanent ladder or steps. Local amendments vary a little, so we confirm the numbers with the office that will inspect the job.
Cutting a poured wall without hurting it
Most foundations here are poured concrete eight inches thick or more. We lay out the opening away from beam pockets and point loads, confirm what is bearing above, and saw-cut from outside with a wet diamond blade so the cut is clean and the dust stays down. Wide openings get a steel or treated lumber header designed for the load. The buck frame is sealed to the concrete, the window is flashed, and the joint is caulked with a sealant made for masonry.
The well is a drain, not just a hole
A window well collects water. In clay soil it will hold that water against your new window unless it has somewhere to go. We excavate below the sill, set washed stone, and tie a drain to the foundation drain tile or to daylight where the grade allows. A clear cover keeps leaves and the dog out. Skipping the drain is the usual reason older egress wells leak.
How the work runs
- Location and utility checkChoose the wall, call in utility locates, check for gas, electric and downspout lines outside and framing loads inside.
- Permit and engineeringSubmit the opening size, header detail and well specs.
- Excavate and cutDig the well, saw the opening, remove the slug of concrete, install header and buck.
- Install, drain and finishSet and flash the window, install the well, stone and drain, backfill, then trim the interior.
What moves the price
We do not publish square-foot prices, because they mislead more than they help. These are the factors that actually change the number on a proposal.
- Depth of the dig and what is in the way outside: AC units, decks, gas meters.
- Foundation thickness and whether a structural header is required.
- Well type: galvanized steel, composite stepped wells that look like stone, or site-built timber or block.
- Drain connection method.
How long it takes
Two to four working days on site once the permit is issued and locates are marked, plus interior trim.
Permits
A building permit is required because you are altering the foundation. Inspectors check opening size, sill height, well dimensions and the header. See our guide to which projects need a permit.
Egress Windows questions
Does a walkout basement need an egress window?
A door to the outside satisfies egress for the open area. A bedroom that is closed off from that door still needs its own opening.
Will cutting the foundation weaken my house?
Not when it is laid out and headered correctly. Foundations are cut for windows and doors routinely. The risk comes from cutting under a concentrated load without checking, which we do not do.
Casement or slider?
Casements give the most clear opening for a given frame size, so they usually let you cut a smaller hole.