Why Masonry Repairs Fail: 8 Mistakes That Cost Chicagoland Homeowners Twice

Homeowners assume masonry fails because of weather. Chicagoland weather is genuinely brutal on brick — but in our experience, most of the failed masonry repairs we're called in to look at didn't lose a fight with the winter. They were built wrong, and the winter simply found out.

Masonry is unusually easy to do badly and have it look right. A skimmed joint and a properly cut one look nearly identical on the day the crew leaves. The difference only shows up two or three winters later, by which time the contractor is long gone and the homeowner assumes brick repair just doesn't last.

It does last. Here are the eight mistakes that stop it from lasting, why each one fails, and how to tell whether your house has them. Paul Lally's Masonry has been correcting this work across Chicago and the suburbs since 1988.

1. Mortar harder than the brick

This is the most destructive mistake in the trade, and the most common on older Chicago homes.

The principle: mortar is supposed to be the sacrificial element in a wall. It should be softer than the masonry units around it, so that thermal expansion, moisture movement, and minor settlement are absorbed by the joint. A joint is inexpensive and straightforward to replace when it wears out. That's the design.

The mistake: using a modern, high-strength, Portland-rich mortar because "stronger is better." On a hundred-year-old Chicago common brick or a soft hand-molded greystone unit, that mortar is now harder than the brick beside it.

What happens: the physics invert. The joint no longer yields, so all that movement has to be absorbed by the brick instead. The brick face spalls at the joint edges, flaking and crumbling along every line of mortar. Every freeze cycle takes a little more.

Why it's the worst one: it is not reversible. Repointing can be redone; brick faces cannot be put back. A "stronger" repair quietly destroys the wall it was sold to protect.

How to spot it: repointed joints that look crisp and grey and modern while the brick immediately beside them is flaking, powdering, or has lost its face. On pre-1930s masonry, soft lime-rich or low-Portland mixes are usually correct — see our guide to mortar matching for tuckpointing and historic masonry restoration and lime mortar.

2. Joints not cut deep enough

The principle: a repointed joint needs real depth for the new mortar to key into — generally about two to two and a half times the width of the joint, cut back until sound mortar is reached. On a standard residential joint that lands somewhere around three quarters of an inch.

The mistake: cutting a shallow groove, or barely scratching the surface, because grinding is the slowest and least pleasant part of the job.

What happens: the new mortar has almost no surface area to bond to and no mechanical key. It sits in the joint like a filling with nothing gripping it. A few freeze-thaw cycles later it crumbles and falls out — and underneath, the original failing joint has been letting water in the whole time.

How to spot it: mortar that has crumbled out within a couple of years, or joints that look shallow and flat rather than recessed and compacted.

This is why a job that finishes suspiciously fast is not a bargain. The grinding is the job. Our post on how long tuckpointing takes walks through realistic timelines.

3. Skim pointing — smearing new mortar over old

The specific, widespread version of mistake #2, and it deserves its own entry because it's the single most common bad masonry job in Chicagoland.

The mistake: rather than cutting anything out, a thin layer of fresh mortar is smeared across the face of the existing failing joints, sometimes riding up onto the brick.

What happens: it looks fantastic for a season or two — uniform, clean, brand new. Then it sheets off in flakes, because it was never bonded to anything but soft, failing material. Meanwhile the original joint has continued admitting water for that entire time, and the skim coat has been holding that water against the wall.

How to spot it: mortar riding onto the brick faces, joints that look "painted on," a joint profile that doesn't match the untouched sections of the wall, or a wall where the mortar looks newer than the brick in a way that reads flat rather than recessed.

4. Caulk where mortar belongs

The principle: mortar goes in joints that are designed to hold still — the bed and head joints between bricks. Flexible sealant goes only in joints designed to move: expansion and control joints, window and door perimeters, coping joints, penetrations, and transitions where masonry meets a different material.

The mistake: running a bead of caulk into open mortar joints, cracks, or along a brick course because it's fast and it stops the visible draft.

What happens: the sealant has no business bonding to two brick faces across a static joint. It fails at the bond line, but before it does, it holds water in the joint instead of letting the masonry dry — which is worse than the open joint was. And it makes the eventual proper repointing harder, because every trace of it has to come out first.

How to spot it: rubbery, glossy, or discolored material in the brick joints rather than mortar. Our post on caulking vs. tuckpointing covers the distinction, and masonry caulking in Chicago covers where sealant genuinely belongs.

5. Film-forming sealers that trap moisture

The principle: masonry always carries some moisture, and it has to be able to release it as vapor. Any sealer used on Chicagoland brick must be breathable and vapor-permeable — a penetrating product that soaks in and disappears.

The mistake: applying a glossy film-forming "waterproofer," a masonry paint, or an elastomeric coating to the outside of a brick wall.

What happens: the coating locks existing moisture inside the brick. Winter comes, that trapped water freezes and expands roughly nine percent, and it has nowhere to go — so it pushes the hard fired face off the brick. The product sold as protection is what caused the spalling.

How to spot it: a visible sheen or film on the brick, paint on masonry that's bubbling or peeling, and spalling concentrated on the coated elevations. See is masonry waterproofing worth it.

6. Sealing before repairing

Closely related, and a sequencing error rather than a materials one.

The mistake: applying sealer to a wall whose mortar joints are still failing.

What happens: the overwhelming majority of water entering a brick wall comes through failed joints, not through the face of the brick. Sealing the face does nothing about that path — it just coats it, conceals it, and slows the wall's ability to dry out afterward.

The correct order is always: fix the water paths (repoint, replace spalled brick, address the lintel, crown, coping, and caulking) → fix the drainage (gutters, downspout discharge, grade) → clean and dry → then seal, if sealing is warranted at all.

If a contractor proposes sealing a wall with visibly failing joints and doesn't raise repointing first, that tells you a great deal about the rest of the work.

7. Aggressive cleaning

The principle: fired brick has a hard outer face and a softer interior. Limestone has a durable weathered skin. Both are protective, and both are thin.

The mistake: sandblasting, or high-pressure washing at settings meant for concrete, to make an old wall look bright.

What happens: the protective face comes off with the dirt. What's left is porous, absorbent material that drinks far more water than it did before — so it spalls faster, effloresces more, and deteriorates on a much shorter clock. On carved or tooled historic stone, it also erases detail permanently.

How to spot it: brick with a uniformly rough, matte, sandy surface across a whole elevation; stone with softened, blurred edges where tooling used to be crisp.

Historic masonry gets cleaned with the gentlest effective method, not the fastest one.

8. Repairing the symptom while the cause keeps working

The most expensive mistake, because the money spent is entirely wasted.

The mistake: patching a crack, replacing spalled bricks, or repointing a section without diagnosing why it failed.

What happens: the cause is still there. Some common ones in Chicagoland:

• A rusting steel lintel over a window or garage opening. Corroding steel expands to several times its thickness and lifts the brick above it. Patch the crack and it reopens within a season — see failing lintels and cracked brick above windows.
• A gutter or downspout dumping water at one corner of the house.
• Grade sloping toward the foundation, or soil and pavement sitting too high against the wall.
• A cracked chimney crown or missing cap letting water down the inside of the chimney.
• Failed coping on a parapet, running water down inside the wall — the reason so many "roof leaks" survive a new roof.
• Active foundation movement, which is a structural question rather than a masonry one.

The test to apply: if your mason explained why the damage happened before proposing what to do about it, you're in good hands. If the conversation went straight to scope and price, be careful. Our guide to step cracks in brick walls is essentially a long version of this point.

The eight, at a glance

Mistake	Why it fails	Reversible?
Mortar harder than brick	Brick becomes the sacrificial element and spalls	No — brick faces are lost permanently
Joints not cut to depth	New mortar has nothing to key into	Yes — redo it properly
Skim pointing	Bonded only to failing material; sheets off	Yes — cut out and repoint
Caulk in mortar joints	Holds water against the wall; fails at the bond	Yes — remove and repoint
Film-forming sealer	Traps moisture; freeze cycle spalls the face	Partly — damage already done is permanent
Sealing before repairing	Coats the leak path instead of closing it	Yes — repair, then reseal
Aggressive cleaning	Strips the protective face off brick and stone	No — the face doesn't come back
Ignoring the cause	Symptom returns; money entirely wasted	Yes — diagnose and fix the cause

Two of those eight are permanent. That's the case for getting it right the first time.

Why Chicagoland punishes these mistakes specifically

Every one of these errors would be survivable in a mild, dry climate. Here they aren't, for three reasons.

Freeze-thaw cycling. Water absorbed into masonry expands about nine percent when it freezes. We get repeated hard cycles — sometimes several in a single week — so any mistake that puts or holds extra water in a wall gets tested dozens of times a winter.

The age and softness of the housing stock. The bungalow belt, the greystones, the two-flats and three-flats, the brick storefronts — most built between roughly 1890 and 1930 with soft, locally-fired common brick and lime-based mortar. That masonry is genuinely durable when treated correctly and genuinely fragile when treated like modern brick. It is exactly the material that hard mortar and aggressive cleaning ruin.

Wind-driven rain and lake-influenced moisture push water at walls horizontally rather than letting it run down the face, finding every joint that isn't right.

How to protect yourself when hiring

Ask questions that a competent mason will answer specifically and an incompetent one will answer vaguely:

• "How deep will you cut the joints, and why that depth?"
• "What mortar type and mix are you using, and how did you decide?" (On pre-1930s brick, an answer that doesn't mention the brick's softness is a bad sign.)
• "What caused this damage?" — before any scope discussion.
• "Are you sealing anything, and what's the order of operations?"
• "How will you clean the masonry?"
• "What will you do about the gutter / lintel / grade?"

A written scope should say where the work happens, what is being removed and replaced, what materials are being used, and how the joints will be finished. Our post on how to hire a masonry contractor in Chicago goes deeper, and what a masonry estimate should include covers the paperwork side.

And be skeptical of speed. A crew that repoints a two-story house in a day and a half skipped the grinding.

Maintenance that keeps a good repair good

Even correct work needs the water managed around it:

• Keep gutters clear and downspouts discharging well away from the foundation.
• Maintain grade sloping away from the house; don't let soil or mulch build up against the brick.
• Keep snow from being piled against foundation walls.
• Check the chimney crown and cap and the coping on any flat-roofed building — the top of the masonry is where water gets in.
• Look at the wall each spring after the freeze-thaw season, especially north and west elevations and the bottom three courses.
• Re-seal on schedule if the wall was sealed with a breathable product.

Our masonry maintenance checklist for Chicago lays out a full cadence.

Related services

If you're looking at work that didn't hold, the correction usually falls under tuckpointing and repointing, brick repair, brick replacement, lintel repair and replacement, chimney repair and rebuilds, parapet wall repair, limestone and sill repair, caulking and joint sealant, masonry waterproofing, residential masonry restoration, or historic masonry restoration.

The bottom line

Masonry repair that fails within a few years didn't fail because of Chicago weather. It failed because a step was skipped — usually the joint depth, the mortar hardness, or the diagnosis. Six of the eight mistakes here are correctable. Two of them — hard mortar against soft brick, and aggressive cleaning — permanently destroy original material, which is why the first repair matters more than most homeowners realize.

Paul Lally's Masonry Inc. is a family-owned, insured masonry contractor serving Chicago and the Chicagoland suburbs since 1988 — tuckpointing, brick repair and replacement, chimney repair and rebuilds, lintel replacement, masonry restoration, and waterproofing for residential and commercial properties. Built on Craftsmanship. Backed by Experience.

If you've had work done that isn't holding, we'll walk it with you and tell you honestly what was done, what needs correcting, and what can be left alone. Our family name is on every job we do.

Free on-site estimates — call (708) 448-8866 or request an estimate online.