Window well, steel lintel, drainage and cost for cutting a code-legal basement egress opening.
Estimates are planning aids, not a professional quote. Double-check quantities and product coverage — and any local code or permit requirements — before you buy.
⚠ Cutting a structural opening into a poured concrete foundation almost always means cutting through vertical rebar. Have a structural engineer size the lintel and confirm the wall isn't load-bearing for anything above it before you cut — most owners sub this specific step out.
⚠ This is a permitted structural alteration in nearly every jurisdiction, not a cosmetic swap. Get the permit and inspection scheduled before you cut the wall.
| Doors & Windows | $781–$1,057 |
| Fasteners & Hardware | $123–$167 |
| Connectors & Brackets | $109–$147 |
| Drainage | $68–$92 |
| Membrane & Fabric | $26–$35 |
| Total | $1,107–$1,497 |
Excludes tools, delivery, tax and permit fees. Labor not included — this is a DIY materials estimate.
These are affiliate links: we may earn a commission if you buy through them, at no extra cost to you. It never changes what the calculator recommends — the shopping list comes from your dimensions, not from what pays.
About this calculator
Enter your foundation wall type and thickness, the rough opening size, and how deep the window well goes, and the calculator prices the whole below-grade opening: the egress-rated window unit, a steel lintel to carry the wall above it, a window well with a gravel drainage base, and the waterproofing that keeps the cut from becoming a leak point. It checks your clear opening against the IRC's 5.7 square foot minimum escape area as you adjust the numbers, so you know before ordering whether your size actually passes.
Switch between a poured concrete or block foundation, since the cutting method and difficulty differ, and choose a casement or slider window — casement units open fully and clear code with a smaller pane, while sliders only open halfway and need roughly double the glass to pass the same minimum. Open the advanced options to set the window well material, add a drain tie-in and cover, and include waterproofing membrane. A permanently affixed ladder is added automatically once the well passes the 44 inch code depth that requires one.
Step by step
A step-by-step walkthrough to go with your plan above. Follow the product instructions and any local code or permit requirements as you work.
Check your opening size against the local egress minimums — clear area, width, height and max sill height — before you order anything, and get the permit and inspection scheduled. This is structural work in nearly every jurisdiction.
Temporarily support the wall and framing above the cut line if the wall carries any load, then lay out the opening on both faces of the wall so your cut lines match front to back.
Cut a poured wall with a wall saw or hand-held diamond saw, watching for rebar, or core the block wall with a rotary hammer along the layout lines. Break out and remove the cut section with a sledge and pry bar.
Set the lintel across the top of the opening with full bearing on solid wall at both ends before anything else goes in — it's what carries the load the cut-out wall used to.
Excavate to the well's width, projection and depth, sloping the floor slightly toward the drain if you're tying one in, and keep the sides stable while you work.
Level a gravel bed in the pit, set the well against the foundation and anchor its flange to the wall, then backfill around the outside so it can't shift.
Lap waterproofing membrane over the sill and jambs, down into the well, then set the window plumb and level in the opening and seal its perimeter.
Install the well ladder or steps if the depth requires one, add the cover, and call for your inspection before backfilling anything you'd need to expose again.
Equip the job
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Concrete & Masonry
Answers
The IRC (R310, with local amendments common) requires at least 5.7 sq ft of clear openable area — 5.0 sq ft if the sill sits at or above grade — with a clear width of at least 20 inches and clear height of at least 24 inches, and the sill no higher than 44 inches above the finished floor it serves. All of those minimums apply to the openable area once the window is installed, not the rough opening you cut, so the unit itself needs to be sized larger than the bare code numbers to leave room for frame and sash.
Almost always, yes. Cutting a new opening into a foundation wall is structural work and, for a basement bedroom, is usually required by code in the first place, so it triggers both a building permit and an inspection. Skipping the permit can leave you without a legal bedroom and can complicate a sale or insurance claim later — check with your local building department before you cut.
The well needs to run from grade down to at least the bottom of the window opening, and if that floor ends up more than 44 inches below grade, code requires a permanently affixed ladder or steps that stay clear of the well's required open area. The well itself also needs enough horizontal projection — typically at least 36 inches, more for deeper wells — for someone to actually climb out, not just enough width to fit the window.
A casement window cranks fully open, so almost its entire glass area counts toward the code-required clear opening — it clears the minimum with the smallest overall window. A sliding window only opens halfway, so the operable half alone has to meet the 5.7 sq ft minimum, which means a slider needs roughly double the total glass area of a casement to pass the same code check. Casement is the more compact, cheaper-to-frame choice; slider suits openings where a crank-out sash would hit the well wall.
Start with a gravel bed under the well so it can't hold standing water like a bucket, then tie a short drain into your sump pit or daylight it away from the foundation rather than leaving the well to rely on the gravel alone — that combination is what this calculator's drain tie-in option adds. A well cover keeps out most rain and leaves to begin with, and grading the surrounding soil to slope away from the well stops surface runoff from adding to the load.
A CMU block wall is within reach for an experienced DIYer with a rotary hammer and masonry blade, working carefully and confirming the wall isn't load-bearing above the cut. A poured concrete wall is a different job — you're almost certainly cutting through vertical rebar, the cut needs to be square and clean for the lintel to bear properly, and a mis-sized or unsupported opening risks the wall above it. Most owners sub that specific cut out to a concrete-cutting contractor and DIY the rest — the well, drainage, waterproofing and window install.