Window Replacement in a Brick House: Methods and Pitfalls

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Replacing windows in a brick house is doable, but it is a different job from swapping windows in a siding-clad home. You can’t peel back siding to reach the frame, so the choice of method, the measurements and the water management at the sill decide whether the new windows last 25 years or start leaking inside five. Most brick homes are best served by an insert (pocket) replacement when the old frame is sound, and by a full-frame replacement when it isn’t.

Below, we walk through how the two methods compare, how to measure a masonry opening, how flashing and weep holes should work, what the process looks like, and when to call a pro.

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Plan Your Brick Window Replacement
Star Windows Solutions provides window replacement and repair for residential and commercial properties across the Kansas City area.

TL;DR

  • Brick openings leave little room for error, so the method matters: inserts keep the existing frame, while full-frame jobs replace everything and cost more.
  • Choose full-frame when the old frame is rotted, insect-damaged, or there are signs of water getting in around the opening.
  • Measure the exterior brick-to-brick opening as well as the interior one, and use the smallest dimension.
  • Use a sill pan, shingle-style flashing, and leave the sill and the bottom edge able to drain. Never caulk away the path water uses to escape.
  • Stained plaster, soft trim or a musty smell near a window deserves a look before you order anything.

Table of Contents

Why brick changes the job

In a wood-framed house with siding, an installer can cut back the siding, lift the housewrap, set the window and tape it in. Brick doesn’t allow that. Masonry openings are difficult and expensive to alter, and tying a new window into the existing weather barrier is much harder when brick is in the way, as Fine Homebuilding’s guide to installing a replacement window in a brick house explains.

Most brick homes built in the last century or so are brick veneer: a single layer of brick standing off a structural wall, with an air space behind it. Water that gets past the brick is supposed to run down that cavity and leave through weep holes. Most brick veneer should have weep holes above the lintel for exactly that reason. A window installation that blocks or ignores that system can trap water inside the wall.

The practical consequences:

  • The opening is fixed. You can’t enlarge it casually, so the new window must fit what is there.
  • Mistakes are expensive to correct. A wrong-size order means a restocking fee, a wait, and an open hole in the meantime.
  • Leaks hide. Water can enter the wall cavity through and around a window, and the resulting damage may go unnoticed for some time.
  • Interior finishes are at risk. Careless removal can crack plaster and damage trim, so the old unit has to come out in a controlled way.

Insert or full-frame: choosing the method

This is the biggest decision, and it drives price, appearance and risk.

Insert (pocket) replacement

An insert replacement removes the sash, the balance system and any storm window, and leaves the existing frame in place. The new window slides into that frame. Fine Homebuilding describes it as the easier, less expensive option, replacing only the sash and balance system.

It suits brick homes because the masonry, the exterior trim and the flashing around the opening stay undisturbed. Trade-offs:

  • The visible glass area shrinks slightly, because the new frame sits inside the old one.
  • It only works if the old frame is square, solid and dry.
  • It can hide problems rather than fix them, since nobody sees behind the frame.

Full-frame replacement

A full-frame job takes out the whole window, frame included, down to the opening. It is generally the better approach if the existing frame is rotted or insect-damaged, or if there is evidence of water intrusion around the opening. It lets the installer inspect the rough opening, rebuild the sill, install a proper pan and flash everything correctly.

It costs more and involves more work around the brick, but it is the only honest fix when the frame is the problem. If you see soft wood, peeling paint at the sill or dark staining, read our notes on window frame rot repair and replacement before deciding.

Quick comparison

Factor Insert replacement Full-frame replacement
What is removed Sash, balances, storm window Entire window including frame
Best when Frame is sound, square and dry Frame is rotted, damaged or leaking
Effect on brick and trim Minimal More disturbance around the opening
Glass area Slightly reduced Full opening used
Cost Lower Higher
Chance to fix hidden water damage Low High

A federal decision-tree approach to window rehabilitation also warns users to check for lead paint and water intrusion before choosing what to do with existing windows. In houses built before 1978, treat paint disturbance seriously and ask any contractor how they handle it.

Special cases in brick: historic buildings and arched openings

Older masonry buildings often have deep reveals, wood sills and unusual shapes. Matching the look, keeping the opening intact and protecting old brick all take extra planning. Our write-up on window replacement in a historic brick building shows what that involves in practice. Arched tops and transoms need custom units, and the arched transom window installation on a brick exterior is a good example of how the opening dictates the product.

How to measure a brick opening

Get this wrong and nothing else matters. A few rules from trade guidance:

  1. Measure width in three places: top, middle and bottom.
  2. Measure height in three places: left, middle and right.
  3. Use the smallest number in each direction. Measure the opening at those points and use the smallest dimension to make sure the unit fits.
  4. Record both openings. The same source says to document the interior rough opening and the exterior brick-to-brick masonry opening, so you know there is room for the unit and the flashing.
  5. Check twice, then again. Fine Homebuilding’s advice is to double- and triple-check before ordering, since a wrong size is an expensive mistake.

The exterior measurement is the one many homeowners skip. On a brick home, the outside opening controls what can physically go in. Our step-by-step guide to measuring windows for replacement covers the basics, though a professional measure on a full-frame brick job is worth having, because the installer owns the result.

Flashing, sealing and weep holes

This is where brick installations succeed or fail, and it is invisible once the job is finished.

The sill pan

A sill pan is a shallow tray under the window that catches any water entering at the bottom and sends it outside. Federal building-science guidance describes a drained installation as one where a pan flashing at the sill collects water and drains it to the exterior, with the jambs and head sealed and the sill left free to drain.

A good pan has:

Flashing order and caulk

Flash the head and the sides shingle-style, so each layer sheds water over the one below. The same JLC guidance says to leave the bottom uncaulked so water can drain, and to leave gaps in the caulk across the head for water to escape. This surprises homeowners who assume more caulk is better. In a brick wall, a continuous bead across the bottom can trap water that should leave.

Flashing layers direct water outward while preserving drainage

Installers who have worked with drainage-style installs also report that isolating the window from the opening works well with careful craftsmanship, and that interior back caulk is key to avoiding callbacks.

Weep holes

Look above the lintel and along the bottom course of your brick. Those small gaps are weep holes. They must stay open. Ask any installer how they will keep them clear and what they do if the old flashing above the opening is missing.

Open weep gaps above a brick window lintel

What the installation looks like

The sequence differs by method, but a careful brick job follows this order:

  1. Inspect and measure. Interior and exterior openings, sill condition, signs of rot or staining.
  2. Remove the old window carefully, preserving the existing weather barrier. For an insert, that means sash, balance and storm window first. For a full-frame job, it means cutting the frame into pieces and prying them out gently instead of forcing it, which protects the brick and plaster.
  3. Prepare the opening. Repair any damaged wood, then fit the sill pan and flexible flashing. Wood rot and framing repair belongs here, not after the window is in.
  4. Dry fit. Test the unit in the opening before any sealant goes on.
  5. Set, shim and square. The window must sit plumb and level, with even gaps so it operates smoothly.
  6. Fill the gap with foam designed for windows, then flash over the flange where the product has one.
  7. Seal selectively. Caulk the sides and head with relief gaps as above, and leave the sill free to drain. Finish the interior back caulk.
  8. Test operation and clean up.

A quality contractor will also test or at least inspect for leaks if you have had trouble before. If you have water stains under a window and don’t know where they come from, start with our hose test for water damage under a window before you spend on new units.

What affects cost

Brick homes cost more per window than comparable siding jobs because the work is slower and less forgiving. The main drivers:

  • Method. Inserts are the lower-cost route, and full-frame is the higher.
  • Frame material. Vinyl, fiberglass, aluminum-clad and wood all price differently.
  • Window size and shape. Large picture windows, arches and octagons are custom.
  • Condition of the opening. Rotted sills, damaged lintels or missing flashing add repair work.
  • Brick adjustments. Any cutting, tuck-pointing or patching around the opening is extra.
  • Number of windows. Doing several at once spreads the setup time.

Online cost guides publish wide ranges, and they vary a lot by region, so we don’t recommend relying on a national average to budget. The reliable way to price your house is a free on-site estimate that separates window cost from labor and from any repair. Sometimes repair is the smarter spend: see why window repair can be significantly cheaper than replacement when the glass or hardware is the only failure.

Our perspective

We see the same pattern on brick homes around Kansas City. The window itself is rarely the problem. The sill is. A homeowner calls about a drafty window, and when we open it up we find a flat, unflashed sill, soft wood behind the trim and a weep-hole row that has been painted or caulked shut.

That is why we push back on the cheapest quote when it says only “replace window.” On brick, the quote should say how the sill will be pan-flashed, how the head will drain, who repairs the wood if it is soft, and how the work will avoid chipping brick and cracking plaster inside.

We also don’t sell full-frame on every job. If your frames are sound, an insert is a perfectly good answer and saves you money. If they aren’t, putting a new window into a bad frame only buries the problem. We would rather tell you that at the estimate than meet you again in two winters.

One more thing we tell property managers: because brick openings are hard to change, specify the right product once. Glass type, hardware, and frame material are far easier to decide before the order than after.

— Artem

When to hire a professional

There is a real DIY path for a single, sound, standard-size insert. But hire a pro when:

  • The frame is soft, stained or insect-damaged, which makes it a full-frame job.
  • The opening is arched, oversized or non-standard.
  • The house predates 1978 and you may be disturbing lead paint.
  • You see interior water stains, peeling plaster or mold near the window.
  • You are replacing windows across a rental or commercial brick building, where consistent results and documentation matter. We handle commercial window replacement as well as residential.

Questions to put to any installer:

  1. Will you do an insert or full-frame, and why for my house?
  2. How do you flash the sill and head, and will you install a sill pan?
  3. How will you keep weep holes open?
  4. Who measures, and what happens if the unit arrives wrong?
  5. What is included if you find rot once the old window is out?

Get an estimate for your brick home

Star Windows Solutions replaces and repairs windows, doors and glass for homes and commercial properties in the Kansas City area. Our estimates are free, financing is available, and one crew can handle the window, the wood rot behind it, the hardware and the siding or caulking around it. See our window and glass services in Kansas City or the window repair and replacement page to request a visit. If you only want to know what shape your windows are in, our window tune-up starts from $99; details are on our homepage.

FAQ

Is it hard to replace windows in a brick house?

It is harder than in a sided home. The opening can’t be changed easily, and connecting the new window to the existing weather barrier is tricky with brick in the way. An insert in a sound frame is manageable for an experienced installer, while full-frame work and flashing take more skill.

Should I choose insert or full-frame replacement for brick?

Choose an insert if the existing frame is sound, square and dry, since it is the easier, lower-cost route. Choose full-frame if the frame is rotted or insect-damaged or you have signs of water intrusion, because that lets the installer repair and flash the opening properly.

How do I measure windows in a brick home?

Measure width at the top, middle and bottom, and height at the left, middle and right, then use the smallest figure. Record both the interior rough opening and the exterior brick-to-brick opening. Check everything more than once before you order.

Do I need to caulk all the way around a brick window?

No. The sill should be left free to drain, and caulk across the head should have gaps so water can escape. Sealing every edge can trap water in the wall and cause the damage you were trying to avoid.

How much does it cost to replace windows in a brick house?

It depends on the method, the frame material, window size and any repairs to the sill or brick around the opening. Because it varies this much, the dependable answer is a written on-site estimate. We offer free estimates in the Kansas City area.

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