How to install new basement windows in poured concrete, block or a wood buck

Yes. You can replace a basement window yourself if the new window fits the existing opening. The work runs the same way in every wall: take out the old frame, dry-fit, shim, fasten, foam and seal. The wall decides how the old frame comes out and what the new one screws into. Once you cut the foundation to make the opening bigger, it becomes an egress job with a permit, a structural cut and often a window well.

TL;DR

• A same-size swap is a realistic DIY job in poured concrete, block or a wood buck. Expect to need a reciprocating saw with a metal blade, a hammer drill with a masonry bit, shims, concrete screws and low-expansion window foam.¹²³
• Measure the rough opening from inside and outside before you order, and before you tear anything out. A wrong-size window can cost you a few weeks of waiting on the next one.³
• Old steel frames cast into poured concrete are the hardest part of the job. Block walls and wood bucks mostly change how you fasten the new window.
• Cutting the foundation for a bigger window is structural work. If that opening serves a bedroom, it has to meet egress size under the 2021 International Residential Code, section R310, as your local building department has adopted it.⁴
• National installed prices run $450 to $1,500 for a standard single-hung window, while a full egress install averages $6,000 to $8,000.⁵⁶

Can I replace a basement window myself?

Yes, when the new window fits the hole that's already there. A same-size swap in a poured, block or wood-buck opening needs a reciprocating saw, a hammer drill, shims, concrete screws and window foam. The first window is the slow one. Hand off anything that cuts or enlarges the foundation to a licensed contractor.

The evidence for DIY is good. The two top-ranking how-to videos for this search both show a homeowner-level swap in a concrete wall.³¹ A couple who describe themselves as "not professionals" replaced the windows in their 1970s walk-out basement, including a large slider, with off-the-shelf units.²

None of them made it look effortless. Andrew Thron says he fumbled through his first two windows before he worked out the fastest way to free the old frame.¹ The Grovehouse couple broke three drill bits on their first night of drilling into the old metal frame.² The Home RenoVision DIY host frames it this way: if you can do a basement window, you can do any window or door in the house.³

The window itself is small, and the concrete is what makes it slow.

Bring in a pro if any of these apply:

• You want a bigger opening. That's a foundation cut and a permit, covered below.
• Water comes through the wall around the window, or the concrete around the opening is cracked or crumbling. That's a moisture or structural question first.
• The room is, or will be, a bedroom and the current window is too small to climb out of.

What kind of wall and frame do you have?

Look at how the old window meets the wall before you buy anything. Basement windows usually sit in one of four setups: a metal frame cast straight into poured concrete, a steel buck, a frame set into a concrete block opening, or a wood buck. Each one comes out differently and takes screws differently.

A buck is a box set into the foundation opening that the window fits into. Steel bucks are deeply embedded steel boxes that hold a window insert or sash.⁷ Wood bucks are lumber frames fastened inside the masonry opening, so the window screws into wood instead of concrete.

How do you replace a basement window in poured concrete?

Remove the sash and glass, then cut the old metal frame and pry it out. Clean the opening, dry-fit and shim the new window, and fasten it with concrete screws. Fill the gap with low-expansion foam, trim it once cured, and seal the outside. Freeing the old frame is the slow part.¹⁷³

1. Measure twice, then order

Measure from inside and outside. The Home RenoVision DIY crew's first order came in the wrong size, and the second fit the concrete opening but not the framed wall inside it.³ Replacements usually take a few weeks to arrive, so check your numbers before the old window comes out, especially in winter.³

For width, measure between the side jambs at the top, middle and bottom and write down the shortest. Do the same for height at the left, center and right.⁵ Order something slightly smaller than the rough opening in both directions.¹ Old basement openings are often not a standard size, so expect gaps to fill.²

2. Take out the sash and glass

Remove everything except the frame: sashes, louvers, screen and glass.⁷ Getting the glass out in one piece is safer than smashing it.³ If the drywall wraps into the window with metal corner bead, pull the bead carefully. It's sharp and it rusts.³

3. Cut the old frame

Put a metal-cutting blade in a reciprocating saw. Andrew Thron cuts the top center of the frame, then pries the sides loose and wiggles the bottom free.¹ All About Doors & Windows cuts the middle of the bottom instead and works one side at a time with a pry bar.⁷ Steel is harder than aluminum. With a steel frame you'll probably need to cut every side.⁷

4. Clean and square the opening

Vacuum the dust and debris.¹ Then check for concrete that sticks into the opening. All About Doors & Windows found a ridge of concrete under their window and had to knock some out so the opening was square.⁷ The Home RenoVision DIY host chiseled out a trough left by the old frame so foam, and not stone, would sit in line with the glass.³

5. Trim the nailing fins

Off-the-shelf windows often come with nailing fins for new construction. Score them with a utility knife and snap them off.¹²

6. Dry-fit and shim

Set the window in right side in and right side up.⁷ Shim the top, sides and bottom for an even gap, then check it's plumb and level.¹ Keep the window as tight to the sill as you can for the moisture seal, while leaving room to get foam in.³ On a bigger window, check it's square too, or it won't operate properly.³

7. Fasten it to the concrete

Pull the sashes and screen so you can reach the screw holes, then drive concrete screws along the sides and top.⁷ You'll need a hammer drill and a masonry bit.² If you're drilling through leftover metal frame, drill it before the new window goes in. The Grovehouse couple found the heat from drilling metal started to melt their vinyl window.²

Both video hosts skipped screws and relied on foam to hold small windows.³¹ Andrew Thron still suggests screwing into the foundation if you want extra security.¹ Use the screws anyway, for a mechanical hold that doesn't depend on the foam alone.

8. Foam the gap

Use low-expansion foam labeled for windows and doors. High-expansion foam can bow the frame so the window won't open.³ Close and lock the window while the foam cures.³ Foam the exterior gaps, then the interior side, and go light on the trigger.¹

9. Trim the foam and shims

Give the foam a couple of hours, then snap off the shims and cut the excess flush with a utility knife.¹

10. Seal the outside

Patch any big gap along the bottom with rapid-setting concrete, then seal the sides and top with a high-quality exterior sealant.¹ The Grovehouse couple used a liquid flashing product around the outside.² Check the sealant's temperature range on the label if you're working in the cold.³

11. Finish the inside

Caulk the inside gap between the concrete and the window.⁷ In a finished basement you'll then add a jamb extension and casing.³

How do you replace basement windows in a cinder block foundation?

Follow the same sequence as poured concrete: remove the sash, cut and pry the old frame, dry-fit, shim, fasten, foam and seal. What changes is where the screws go. Block has hollow cores, so set concrete screws into solid block, a filled core or a wood buck, and keep the opening's top support intact.

Removal is usually similar when the old frame is metal set into the masonry: cut it with a metal blade and pry it out one side at a time.⁷

Fastening needs more thought. A concrete screw driven into a hollow core has little to bite on. Look at the opening edges before you drill. Some block openings have solid or grouted block at the jambs, or a wood buck already lining the hole. If the only thing you can reach is hollow block, a wood buck anchored to the block gives the window a solid surface to screw into.

Leave the lintel alone. That's the beam or reinforced block across the top of the opening that carries the wall above. Cutting into it is a structural change and a job for your contractor.

Block is also the easier wall to enlarge. Cutting an opening in poured concrete typically takes longer and costs more than cutting one in concrete block.⁶

How do you replace a window set in a wood buck?

Remove the sash, then take out the screws or nails holding the old window to the wood buck and lift it out. Check the buck for rot. If it's sound, set the new window, shim, screw through the side jambs into the wood, foam and seal. If it's soft, replace the buck with treated lumber or PVC.

A wood buck makes fastening easy and moisture the main risk. Regular wood can absorb water and swell or shrink in the frame, which opens gaps and warps the fit.² Wood is also susceptible to rot.⁵ Push a screwdriver into the bottom of the buck. If it sinks in, the buck has to come out before the new window goes in.

The Grovehouse couple used PVC trim boards, one 1/2-inch and one 3/4-inch, to prop the new windows and fill the gaps because PVC resists water.² The same logic applies to a rebuilt buck.

With a steel buck, you may not need to touch the frame at all. Some basement windows use a steel buck that houses a replaceable insert, and swapping only the insert is its own simpler job.⁷

Should you install from inside or outside?

Plan to work from both sides. The sash comes out and goes back in from the inside, where you'll also caulk and trim.⁷ The exterior foam, concrete patch and sealant go on from the outside.¹ The question is which side you set the window from, and that depends on access and finishes.

Set the window from the inside when:

• The window well is shallow or tight and you can't get a level and a drill in comfortably.
• The basement is unfinished, so there's no drywall to protect.

Plan more outside work when:

• The basement is finished. Working from inside then means protecting or opening finished walls. The Home RenoVision DIY crew had to open up the interior wall around the window because the drywall ran straight into the jamb.³
• The mess is heavy. The same host notes it's easier to clean up the mess outside than inside.³

If you knock a hole in the drywall while working, window foam can fill it. Trim it flush once hard, then give it a couple of coats of joint compound and paint.³

When does a bigger window turn into an egress job?

The moment you cut the foundation. An egress window is an emergency escape and rescue opening big enough to climb out of. Under the 2021 International Residential Code, section R310, it needs a net clear opening of at least 5.7 square feet, 24 inches high and 20 inches wide, with its bottom no more than 44 inches above the floor.⁴

A like-for-like replacement is treated differently. Section R310.5 exempts a replacement window from those size rules when it's the manufacturer's largest standard size that fits the existing frame or rough opening. It has to be the same operating style, or a style with an equal or larger opening, and it can't be part of a change of occupancy.⁴ A same-size swap that meets those conditions falls under it.

Cutting a bigger hole is a different project. Section R310.7 requires egress openings for new sleeping rooms created in an existing basement. Other basement alterations and repairs don't trigger one.⁴ So if the room is, or will become, a bedroom, the enlarged opening has to meet the full egress window requirements.

Below grade, an egress window also needs an area well. Section R310.4 sets it at no less than 9 square feet, with at least 36 inches of projection and width.⁴ Wells deeper than 44 inches need a permanently fixed ladder or steps.⁴ The well also has to drain into the foundation drainage system, unless the soil is well drained.⁴

Local building departments adopt and amend the code, so their version is the one that counts. Most municipalities require a permit for egress work because it involves structural changes to the foundation.⁶ The installers excavate the well, cut through the foundation wall, frame the opening and set the window and well, which takes 2 to 3 days on average.⁶ Cutting a foundation is structural work. It belongs with a licensed contractor who pulls the permit and books the inspections.

If you're adding bedrooms or planning a basement apartment or in-law suite, each sleeping room needs its own egress opening.

What does it cost to replace basement windows?

A standard window replacement costs $450 to $1,500 per window installed, using national figures for single-hung windows in basic vinyl or aluminum frames.⁵ Window style, size, frame material and any concrete repair move that number. An enlarged egress opening is a separate job, and its cost averages $6,000 to $8,000.⁶

HomeGuide's national figures cover windows in general, and none of its lines price a basement window on its own. The table uses its window replacement guide dated February 5, 2026, and its egress guide dated October 22, 2025. Treat them as a starting point. Concrete work around a basement window is priced at your estimate.

The two egress figures disagree because they measure different things. The $3,000 to $7,000 line is a price for the window type.⁵ The $6,000 to $8,000 average includes the window well, excavation and installation labor, and complex jobs can go past $10,000.⁶ Budget from HomeGuide's egress range, because a basement egress window can't go in without the well and the dig.

A few other numbers help with planning:

• Handymen charge $400 to $1,000 to replace one window, including parts.⁵
• A permit to change a window's size costs $50 to $200 for reframing the opening.⁵ For egress work, permit costs typically run $200 to $500 or more.⁶ The first figure is for reframing a window in general. The second is specific to egress, so use it for a foundation cut.
• A drainage system for a window well costs $1,000 to $4,000.⁶
• Low-E coating adds 10% to 20% to the window price.⁵

What are the best replacement windows for a basement?

For a same-size swap, choose a double-pane vinyl hopper, awning or slider in the largest standard size that fits the opening. Vinyl is budget-friendly and energy efficient. Double-pane glass is the industry standard for replacement. Pick a casement or slider when the window has to work as an egress opening.⁵⁶

Frame material:

• Vinyl is the most budget-friendly egress frame and one of the most popular choices for durability and energy efficiency.⁶⁵
• Aluminum is the cheapest but insulates poorly.⁵
• Wood looks classic but needs more maintenance and can rot.⁵ Below grade, next to concrete and a window well, that's a poor trade.

Glass: double-pane is the industry standard for replacement windows, and triple-pane costs more for better efficiency.⁵

Style depends on the opening:

• Hoppers and sliders were the Grovehouse couple's choice for small and large basement openings.²
• Awning windows hinge at the top and open outward from the bottom.⁵ The Home RenoVision DIY replacement was an awning.³
• Casement windows give a full opening for emergency exits.⁶ Sliders suit spaces with limited vertical clearance, and inward-swing windows suit wells too small for an outward-opening sash.⁶

Size: order the largest standard unit that fits your opening. It fills the gap with less foam, and it matches the condition in section R310.5 for replacement windows.⁴

What are the common problems with basement windows?

The usual complaints are drafts, air leaks and cracks around the frame, along with single-pane glass, rusted steel frames and sashes that stick. The replacement brings its own problems: wrong-size orders, concrete ridges in the opening, and foam that bows the new frame. Window wells that drain poorly can leak.⁷⁵⁶

Problems with the old window:

• Chilly drafts in winter, humid heat in summer, and visible cracks between the window and the concrete.⁷
• Single-pane glass with little or no frame. The Grovehouse basement had panes that simply hinged over two nubs.²
• Condensation between panes, windows that are hard to open or close, and rusted parts.⁵
• Steel frames cast into the concrete, which are hard to remove when the time comes.¹

If a window is sound but drafty, a new gasket may fix it without a replacement.³

Problems during the replacement:

• Ordering the wrong size, then waiting weeks for the next window.³
• A ridge of concrete under the old frame that you only find after it comes out.⁷
• High-expansion foam that squeezes the frame until the window won't open.³
• Broken drill bits and melted vinyl from drilling metal with the window in place.²

Problems with wells: poor drainage around window wells can lead to water leaks.⁶ Fix the drainage before you blame the new window.

Is replacing basement windows worth it?

Usually, when the old windows are single-pane, drafty or damaged, or when you're about to finish the basement. HomeGuide puts the return on new double- or triple-pane windows at 75% to 85% and says they reduce energy costs.⁵ The best time is before framing and drywall.

The general window numbers support it. HomeGuide says replacement is worth it when the existing windows are old, damaged or single-pane.⁵ Its 75% to 85% return covers home windows in general, so use it as a guide for a basement.⁵ Windows usually need replacing after 15 to 30 years.⁵

The timing argument is stronger. Windows, egress and permits are planning decisions to settle before framing. Change a window after the drywall is up and you're cutting drywall returns and patching, as the Home RenoVision DIY crew had to.³ The Grovehouse couple called their window swap "a must" as part of finishing their basement.² If you're planning basement finishing, put the window swap, and any egress cut, at the front of the schedule. The same applies when remodeling a basement that's already finished, where new windows mean opening some drywall anyway.

What a good window quote shows

A good quote names the window, the work and the permit. It lists the exact size, style, frame material and glass for each window. It says how the old frame comes out, what the new one fastens to and how the gaps are foamed and sealed. For egress, it includes the well, drainage and the permit.

When your contractor comes out, ask for a written, itemized quote. Check it covers:

• The window model, size, style and glass package for each opening.
• Removal of the old frame, and who repairs damaged concrete.
• Fasteners, foam and exterior sealant or flashing.
• Interior finishing: jamb extensions, casing, drywall repair.
• For egress: excavation, the foundation cut, the well, the ladder if the well is deep, drainage, and landscape repair.⁶
• Whether the permit is included and who handles it.⁶
• Cleanup, and warranty terms in writing.⁶

Pay on a schedule and make the final payment after the work passes inspection.⁶

Basement Remodeling Co. sends your request to one vetted, licensed basement contractor for your metro. You get a free on-site estimate and a written, itemized quote, and your contractor pulls the permit and books the inspections. Read how matched basement finishing contractors are vetted, or go straight to your metro: Atlanta, Denver, Colorado Springs or Fort Collins.