Egress window cost dataset

The minimums, and what they imply together

The two small numbers do not add up to the big one — 20 by 24 inches is 3.33 square feet against a requirement of 5.7. ⚠️ The figures are the ones Boulder County, Emergency Escape and Rescue Openings (B10) and City of Bismarck, building and development FAQs publish for their own jurisdictions, read on 2026-08-25. The International Residential Code belongs to the ICC and is neither reproduced nor derived here; the arithmetic is ours and your local code decides.

The hole each window type needs, and what that costs

⚠️ This table corrected what we had written before we ran it. A slider needs 95 per cent more opening than a casement, and we assumed that would make it much the dearest; it does not, because sawing is charged by the perimeter and a perimeter grows only with the square root of the area — 95 per cent more area is 40 per cent more cutting, which costs roughly what the cheaper window saves. Where the type does decide something is the row with no price: a single-hung opens only its lower half, so it cannot give the minimum clear height in a wall this short at any width. The dash is not a high number, it is an option that does not exist.

How many openings a basement actually needs

The requirement attaches to the basement itself and to every room used for sleeping, not to every room — which is the answer to the question asked on this search, and it corrects the question rather than answering it. ⚠️ A walkout door satisfies the basement’s own requirement and takes one opening off the count; every bedroom still needs its own.

What has to be cut, and how deep the well is

⚠️ There is a step in the right-hand table and it is not the ladder alone. Past 44 inches the well stops being a piece of bent sheet keeping soil off the glass and becomes a structure retaining soil against your foundation, so it is a different product as well as more digging. The well itself has to be at least 9 square feet with a projection and width of at least 36 inches — bigger than the window in every direction. And the line that gets left out of cheap quotes is the drain: a well that does not drain is a bathtub built against a hole in your foundation, and it empties through the window.

Line items

71% of the reference total comes from estimated rather than official figures; the official half is the labour and the machine time. The reference job is one opening through a poured concrete foundation with a 42-inch well, a casement window, machine access, a cover and a permit: 7.31 square feet of opening, 10.9 linear feet of cutting, 21.4 trade hours. Options that are not selected sit at zero quantity, so the table below is all four window types and all three wall types rather than one job.

The reasoning behind each figure

Casement egress windowestimated, ±41%

• Sized so that the clear passage with the leaf fully open meets the area the building department asks for. ⚠️ Priced per window and not per square foot, because what a window costs has more to do with the unit than with its size — and the size is decided by the arithmetic on this page rather than by taste.
• The dearest of the four and the one that needs the smallest hole, which is the trade that decides this job.

In-swing hopper egress windowestimated, ±41%

• Hinged at the bottom and opening inwards, which is what you use where a well is too tight for a leaf to swing out into it.

Sliding egress windowestimated, ±41%

• ⚠️ The cheapest window here and the reason people over-pay for the job. Only one of the two leaves moves, so the clear passage is about 40 per cent of the opening and the hole in the wall has to be nearly twice the size of a casement’s. On a poured foundation that swaps a few hundred dollars of window for a lot more sawing.

Single-hung egress windowestimated, ±41%

• ⚠️ The lower leaf lifts and the upper one is fixed, so the clear passage is barely over a third of the opening and it is wide and short. That is the shape that fails the height minimum even when the area is right, which is why one of these that fits an ordinary bedroom rarely qualifies as an escape opening.

Wet-cutting the opening in poured concreteestimated, ±45%

• ⚠️ Diamond saw hire and blade wear per linear foot of cut through eight to ten inches of reinforced concrete, cut wet so the silica stays down. It is the single line that makes this job what it costs, and it scales with the perimeter of the hole rather than with the window.
• The perimeter is computed from the opening the chosen window needs, assuming a four-by-three opening — which is why a slider costs more to cut in than a casement even though it costs less to buy.

Cutting the opening in blockestimated, ±43%

• Hollow block cuts faster than poured concrete, with the same wet-cutting and the same care about what the wall was doing before you opened it.

Opening up a framed wallestimated, ±49%

• Cladding and sheathing removed and made good around a new opening, per foot of perimeter. Above ground and in timber, this is carpentry rather than concrete work, and the whole character of the price changes with it.

Propping, cutting out and breaking away the opening

• Needling and propping the wall above, running the saw, breaking out and removing the cut piece — which on a poured foundation is a few hundred pounds of concrete that has to come out of a basement.
• Modelled at about half an hour per linear foot of cut in poured concrete and a third of that in block, plus three and a half hours of setting up and taking down the propping per opening.

Opening up and heading off a framed wall

• Nine hours per opening: needling and propping, cutting the studs, building and setting the header, trimming the opening and making good inside and out.

Lintel or header over the openingestimated, ±47%

• ⚠️ Not optional and not a detail: a hole in a load-bearing wall needs something over it to carry what the wall was carrying. In a foundation that is a steel lintel with bearing each side; in a framed wall a built-up timber header.
• Priced per foot of span plus the bearing, so it scales with the width of the opening — which is another reason the window type moves the price.

Mini excavator for the window well

• Machine time at the published FEMA rate for a compact hydraulic excavator, 45 hp, code 8280. An hour and a half per cubic yard of well, plus an hour of getting it there and away — so it scales with the depth, because a well twice as deep is twice the soil.
• ⚠️ Zero when the machine cannot reach the wall, which does not make the job cheaper — the hours on the line below go up instead.

Digging out, trimming and backfilling the well

• An hour and a half per well plus nearly two per cubic yard, and 3.2 times that where every yard comes out by hand and goes away in a barrow. It scales with the depth for the obvious reason.
• ⚠️ The well has to be at least 9 square feet with a projection and width of at least 36 inches, so the hole is bigger than the window in every direction — and it gets deeper with the basement.

Operating the excavator

• The same hours as the machine, because somebody is sitting in it.

Window well, up to four feet deepestimated, ±44%

• A corrugated steel or moulded composite well big enough to meet the 9 square feet and 36 inch minimums, anchored to the wall.

⚠️ Window well deeper than four feetestimated, ±47%

• ⚠️ A different product rather than a bigger one. Four feet down and more, the well is a retaining structure holding soil back against your foundation wall, so it is heavier gauge or a tiered masonry well, and it has to be anchored for it.
• This is where the price of a deep basement stops being about the window at all.

Draining the wellestimated, ±55%

• ⚠️ The line that gets left out of cheap quotes and the one that does the damage. A gravel-filled sump in the base of the well connected down to the footing drain, or a dry well if there is nothing to connect to.
• A window well that does not drain is a bathtub built against a hole you have just cut in your foundation wall. It fills in the first serious storm and it empties through the window.

⚠️ Fixed ladder or steps in a deep wellestimated, ±48%

• ⚠️ Required once the well is deeper than 44 inches, and it has to be permanently fixed and usable with the window fully open. It is a small line with a large point: the whole opening exists so that somebody can get out of it in the dark, and a four-foot wall of steel with nothing to climb is not a way out.

Well cover or grateestimated, ±60%

• A clear dome or a grate that keeps rain, leaves, children and animals out of an open hole beside the house.
• ⚠️ Whatever goes on it has to be openable from inside the well without tools, or it has quietly turned the escape opening into a trap. That is worth asking about by name.

⚠️ Carrying everything else through the gate by hand

• ⚠️ Four hours per opening, and it is not the soil — that is on the line above. It is the piece of foundation that came out of the wall, which on a poured wall is several hundred pounds of concrete, plus the well, the gravel and the window itself, all of it going one barrow at a time through the gap that stopped the machine.
• Worth knowing what this line does and does not do: hand-digging the well itself costs about what hiring the machine would have, because the extra hours and the plant hire come to much the same on a job this size. What actually costs money is everything that is not soil.

Hauling away spoil and the cut-out wallestimated, ±43%

• Soil out of the well and the piece of foundation that came out of the wall, by the cubic yard, charged by weight at the tip.

Flashing, sealing, trimming and making goodestimated, ±51%

• Flashing and sealing the window into the opening, a finished return inside, and making good the wall surfaces on both sides. ⚠️ On a foundation this is what stops the new hole becoming the wettest place in the basement.

Fitting, flashing and finishing

• Five and a half hours per opening for setting, packing, flashing and trimming.

Permit, drawings and inspectionestimated, ±56%

• ⚠️ Not the line to save on, and the SERP asks about it directly. Cutting a hole in a load-bearing wall is structural work and an escape opening is life safety, so this is permitted and inspected work essentially everywhere — and the permit is what later proves the room is a bedroom.
• Unpermitted egress work is exactly what a buyer’s inspector and an appraiser look for, so the money saved by skipping it is spent again when the bedroom stops counting as one.

Not included in this dataset

Finishing the basement around it

Framing, insulation, drywall, flooring and the rest of turning a basement into rooms is priced whole on our basement finishing page, which now takes its egress window figure from this model rather than carrying one of its own.

What it does to an appraisal

⚠️ Two of the four questions Google shows on this search are about value, and this page does not answer them with a number. There is no federal series for what a legal bedroom adds to a house, it varies by market more than almost anything else in property, and inventing a figure would be worse than leaving it out. What is publishable is the other half: what it costs, and the fact that without this opening the room is not a bedroom no matter what it is furnished as.

Structural engineering where the wall needs it

A wide opening, a wall carrying a point load, or a foundation already moving is a case for an engineer’s drawing rather than a standard lintel. The permit will usually say so, and it is money well spent — the alternative is finding out afterwards.

Whether the ground outside will let you

⚠️ A well needs somewhere to go. A property line, a paved drive, a neighbour’s wall or a buried service on the outside of that wall can make one position impossible and another expensive, and none of that is visible from inside the basement. It is the first thing to check and it is not in this figure.

The code itself

The minimum dimensions are set by the International Residential Code, which is a copyrighted document published by the ICC and is not reproduced or derived here. The figures on this page are the ones two municipal building departments publish for their own jurisdictions, said in our own words, and the arithmetic that follows from them is ours. Your local code decides.