Chicago Brick Repair: Efflorescence, Tuckpointing, and Lintel Cracks

Vintage Home Maintenance Series · Part 3 of 7

Brick is the signature of Chicago's housing stock. Bungalows, two-flats, courtyard buildings, and greystones with brick sides and backs have stood for a century or more, and with the right care they'll stand for another. The catch is that "the right care" for century-old masonry is often the opposite of what a modern contractor reaches for first.

This guide covers the four masonry problems we see most in older Chicago homes: worn mortar, white powder on brick, cracks above windows and doors, and painted masonry. It's part of our complete guide to vintage home maintenance in Chicago.

Why Old Chicago Brick Needs Soft Mortar

Much of Chicago's older brick, especially the "Chicago common" brick used on side and rear walls, was fired at lower temperatures than modern brick. It's softer and more porous. Original mortars were lime-based: soft, flexible, and vapor-permeable.

In that system, the mortar is the sacrificial element. Moisture moves through it and evaporates out of the joints, and when the wall expands, contracts, or settles, the mortar absorbs the stress. Every few decades the joints wear back and get repointed. The brick itself lasts.

Repointing with hard, cement-rich mortar (such as Type S or Type N on very soft brick) reverses that relationship. Water can no longer escape through the joints, so it moves through the brick instead, carrying salts to the surface and freezing inside the brick face. The result is crumbling, spalling brick — damage that's far more expensive to fix than mortar.

Mortar Types at a Glance

When Does a Brick Wall Need Tuckpointing?

In Chicago, "tuckpointing" is used for what preservationists call repointing: raking out deteriorated mortar and replacing it with new mortar. Signs it's time:

• Mortar recessed more than about 1/4 inch behind the brick face
• Mortar that crumbles or turns to sand when scratched with a key
• Open joints, or gaps where you can see daylight or into the wall
• Loose bricks, especially at parapets, chimneys, and the tops of walls
• Damp interior plaster on exterior walls after rain

What Good Repointing Looks Like

• Matched mortar. The new mortar is softer than the brick and matches the original's color, texture, and joint profile. Many masons can analyze the existing mortar or mock up samples.
• Proper raking depth. Old mortar is removed to a depth of about 2 to 2.5 times the joint width, down to sound mortar — not just skimmed over.
• No damage to brick edges. Aggressive grinding that widens joints or chips brick edges is a sign of a rushed job.
• Mortar packed in layers and tooled to match the original joint, then kept damp and protected while it cures.
• Right season. Avoid freezing weather and extreme heat; spring and fall are ideal.

What Is the White Powder on My Brick?

That white, chalky residue is efflorescence: water-soluble salts carried to the surface by moisture moving through the masonry. When the water evaporates, the salts stay behind. Efflorescence itself is cosmetic, but it's a reliable sign that too much water is moving through the wall.

The source of that water is the real issue. Common culprits:

• Hard mortar from past repointing, forcing moisture out through the brick instead of the joints
• Leaking gutters or downspouts soaking the wall from above
• Grading and splash-back keeping the base of the wall wet (see Part 2)
• Failed copings or chimney caps letting water into the top of a wall
• Basement walls with water pressure from saturated soil outside

To clean it: brush it off with a dry, stiff natural-bristle brush on a dry day. Avoid pressure washing and water, which dissolve the salts and drive them back into the brick. Avoid acid cleaners on historic masonry unless a preservation-minded mason recommends a specific product. Then fix the water source — or the efflorescence will come back.

What Causes Cracks Above Windows and Doors?

Zigzag, stair-step cracks running up from the top corners of a window or door opening usually point to the lintel: the steel angle that carries the brick over the opening. After decades of moisture, the steel rusts. Rust takes up several times the volume of the original steel, so the lintel swells and lifts the brick above it, cracking the joints. Other signs include rust stains, a lintel that looks bowed or layered with flaking rust, and bricks bulging over the opening.

How Lintel Replacement Works

1. Shore the wall and carefully remove the brick above the opening.
2. Remove the old lintel.
3. Install a new lintel that's primed and painted with a rust-inhibiting coating, or galvanized, with proper bearing on each side.
4. Install continuous flashing over the lintel with a drip edge and end dams, plus weep openings so water that gets into the wall can drain out.
5. Re-lay the brick with compatible mortar, reusing the original brick where possible.

It sounds dramatic, but it's routine work for an experienced mason. Waiting is what gets expensive: the longer a lintel rusts, the more brick above it is damaged. Patching the cracks with caulk or mortar without replacing the lintel doesn't stop the swelling.

Should You Paint Brick or Limestone?

Generally, no. Most paints form a film that traps moisture inside masonry. The water that used to evaporate from the surface now collects behind the paint, which leads to bubbling and peeling, damp walls, freeze damage, and eventually crumbling brick or stone. Painting also commits you to repainting every several years.

If your brick or limestone is already painted:

• Test a small area first to see how well the paint comes off and what's underneath.
• Use the gentlest effective method, typically a masonry-specific chemical stripper and low-pressure water rinse.
• Never sandblast or use high-pressure water on historic masonry. It strips the hard outer face of the brick and leaves it porous and vulnerable.
• Assume old paint contains lead in a home built before 1978, and follow lead-safe practices (see Part 5).
• If removal isn't practical, ask about a breathable mineral (silicate) paint for future coats rather than another layer of film-forming paint.

Masonry Inspection Checklist

Walk all four sides of the house each spring, after the freeze-thaw season. The sides and back, and the chimney, often show problems long before the front.

Hiring a Mason in Chicago

• Ask what mortar they'll use, and why. A mason experienced with vintage brick will talk about matching the mortar to the brick. One who says "Type S for everything" is a red flag for an older home.
• Ask how they remove old mortar. Hand tools or careful grinding that doesn't widen the joints or chip brick edges is what you want.
• Look at past work on buildings of similar age, ideally a few years after completion.
• Confirm licensing, insurance, and permits. Many masonry projects in Chicago require a City permit, and contractors pulling permits generally must be licensed with the City.
• Check for landmark status. If your home is in a Chicago Landmark District, exterior masonry work may require review by the Commission on Chicago Landmarks.

What Masonry Issues Mean When You Buy or Sell

Masonry shows up on nearly every inspection report for a vintage Chicago home. Most of it is normal maintenance, and buyers who understand that can negotiate calmly instead of walking away.

Sellers: Tired mortar and rusted lintels are visible from the sidewalk, and they color a buyer's first impression of the whole house. If you've had recent tuckpointing or lintel work, keep the invoices and permits. A well-documented masonry history is a genuine selling point for brick homes.

Buyers: Efflorescence and some worn joints are routine and fixable. Pay closer attention to widespread spalling, which often signals past hard-mortar repointing, and to bulging walls, loose parapets, or chimneys that lean. For those, get a mason's quote — or an engineer's opinion — during the inspection period.

Frequently Asked Questions

What's the difference between tuckpointing and repointing?

Technically, tuckpointing is a decorative technique using two contrasting mortar colors, while repointing is replacing deteriorated mortar. In Chicago, most people and contractors use "tuckpointing" to mean repointing.

How often does brick need to be repointed?

Well-matched mortar often lasts several decades, and exposed areas like chimneys and parapets wear faster than sheltered walls. Rather than following a schedule, inspect annually and repoint areas as joints deteriorate.

Is efflorescence harmful?

The salt deposit itself is cosmetic. It matters because it shows water moving through the wall, and that moisture can cause real damage. Find and fix the moisture source.

Can I seal my brick with a waterproof coating?

Film-forming sealers are generally a bad idea on old brick because they trap moisture. If a mason recommends a water repellent for a specific problem, it should be breathable, and the underlying water source should be fixed first.

Are cracks above windows a structural problem?

They're usually a localized problem with the lintel, not the whole structure. But they should be fixed promptly, because a rusting lintel keeps pushing brick out of place over time.

This article is for general informational purposes and is not a substitute for advice from a qualified mason, structural engineer, or inspector. Permit and landmark requirements change; confirm current rules with the City of Chicago Department of Buildings before starting work.