Foundation Cutting for Egress Windows

An enlarged opening usually starts where an existing basement window is, because there's already a gap in the wall and often a header above it. The cut is extended downward, since that's where the extra height needs to come from, and sometimes sideways. A brand-new opening can also be cut in a solid stretch of wall where there's room for a well outside.

Poured concrete versus block

Poured walls. Cut with a large walk-behind or track saw, often with water to control dust. The cut edges are clean and the window buck fastens directly to the concrete. Rebar in the wall is cut through as part of the job.
Concrete block walls. The cut exposes hollow cores, which are filled with concrete or mortar so the opening has solid sides. Block walls may need a new lintel over the opening.
Older stone or clay tile foundations. Found under some early homes. These need a careful look before anyone cuts, and some aren't good candidates at all.

Does the wall need extra support?

Often. The wall above an opening carries the house framing, and cutting a wider gap changes how that load reaches the footing. Depending on the width of the cut, where the floor joists run and what the wall is made of, the contractor may add a steel or concrete header, temporary shoring during the cut, or an engineer's detail. In Sioux Falls, a cut in a foundation is building work that needs a permit, and the plan reviewer may ask how the opening will be supported.

Where should the opening go?

Away from the main beam pocket and any posts
Clear of plumbing stacks, the sewer line, gas lines and the electrical service
Not under a deck, step or air conditioner unless those will be moved
Where the yard can be graded so water runs away from the new well

The contractor prices the job after seeing the wall, the yard and the room. We don't quote prices, and a number given over the phone before anyone has looked at the foundation is only a rough starting point.

Where we connect you with help

Common questions

Can I just make my existing basement window bigger?

Usually, yes. The contractor cuts the opening down and sometimes wider to fit a code-size window, and installs a larger well outside. The existing header may or may not be enough for the wider opening.

Is cutting a foundation wall dangerous to the house?

Not when it's planned and supported properly. The risk comes from oversized cuts, missing headers and cuts in the wrong place, which is why a permit and an experienced contractor matter.

Related services

More background: Sioux Falls egress window guide.

Cutting and enlarging basement openings