Why Lintel Repair, Flashing, and Bricklaying Matter in Masonry Restoration

Peter Merlo

At RestoreWorks, we believe in equipping project stakeholders with the technical knowledge they need to protect their buildings from premature deterioration. That’s why we recently partnered with the International Masonry Institute (IMI) to host a hands-on masonry restoration workshop at their Addison, Illinois training center. One of the stations at the event focused on Lintel Repair, Flashing Installation, and Bricklaying, an essential system for preventing water intrusion and extending the life of commercial and historic masonry walls.

If you’re an architect, structural engineer, general contractor, or property manager overseeing masonry assets in the Chicago area, here’s what you need to know.

Why Flashing Matters: Managing the Inevitable Presence of Water

Water in masonry walls is inevitable. Moisture enters through porous materials, hairline cracks, and mortar joints, even when walls appear intact. The goal isn't to keep water out completely, but to capture it and direct it out before it causes damage.

That’s the role of a well-designed flashing system, which acts as a hidden drainage layer within the wall assembly. Flashing, along with components like end dams, weeps, and drip edges, diverts trapped moisture to the exterior, reducing risks such as:

Rust jacking from corroded steel lintels
Efflorescence and staining
Freeze-thaw damage
Degradation of embedded anchors and ties

As the National Institute of Building Sciences points out, “bad details lead to bad workmanship and ultimately poor performance.” That’s why flashing must be installed as a complete system, not an afterthought, especially when restoring aging masonry walls in moisture-prone climates like Chicago.

Instructor demonstrating components of a complete masonry flashing system, including stainless steel drip edge, end dams, weeps, and flexible flashing membrane, during a hands-on training workshop focused on moisture management in masonry walls.

Step-by-Step: How the System Comes Together

Here’s how our team demonstrated proper flashing and lintel repair during the workshop:

#1. Steel Lintel Preparation

Clean and coat the lintel with compatible corrosion-resistant paint.
Make sure it has a slight positive slope away from the wall, never backward.

#2. Sealant & Drip Edge Installation

Apply two continuous beads of sealant on the top face of the lintel.
Set a stainless steel or copper drip edge in place to channel water away from the wall face.

#3. End Dams

Install end dams at both ends of the lintel to stop water from running off the sides.
Flashing should always overlap end dams to create a watertight seal.

#4. Main Flashing Application
Two options were covered:

Thru-wall Flashing: Tuck the top of the flashing into the CMU backup and seal it, preventing water from getting behind.
Termination Bar: Mechanically fastened 12" (or higher if needed) above the lintel, sealed to the wall.

#5. Flashing Material Types

Stainless Steel/Copper Sheet Flashing: The gold standard in durability.
Flexible Composite Flashing: Easier to handle, no asphalt base, but must be stepped properly if used at multiple levels.

#6. Weeps and Drainage Accessories

Mesh weeps were highlighted as the best-performing option. They let water out and air in, supporting drying of the cavity.

IMI instructor presenting flashing materials—including flexible membrane, drip edge, and sealants—at the lintel and moisture control station during the hands-on masonry restoration workshop co-hosted by RestoreWorks.

Brick Installation & Joint Best Practices

Once flashing is in place, bricklaying begins. A few key points for long-term durability:

Mortar Joints Must Be Full: At least 80% solid to avoid shrinkage cracks and moisture tracking.
Head Joints should be tight and fully compressed.
Start at the center of the span and work outward, especially over steel supports.
After setting wall ties or anchors, be sure to seal over them to prevent leaks at connection points.

As Preservation Brief 1 from the National Park Service emphasizes, detailing at the mortar joint level can make or break a restoration project’s effectiveness, especially in freeze-thaw climates like Chicago.

Live bricklaying demonstration at the lintel station during a masonry workshop, showing full mortar joints, proper brick coursing, and installation sequencing over a steel lintel support embedded in the masonry wall.

Chicago-Area Buildings Deserve Better than Band-Aid Repairs

Too often, flashing is omitted or poorly installed in older masonry buildings. Without proper repair, moisture can compromise structural steel, stain façades, and lead to more costly interventions down the road.

At RestoreWorks, we’ve seen firsthand how implementing a complete wall system (starting with lintel prep and ending with solid brickwork) can transform a building’s long-term performance.

If your commercial property, campus, or multifamily building in the Chicago area shows signs of water infiltration, spalling brick, or rusting lintels, it may be time to open the wall and take a closer look.

Let’s Talk About Your Masonry System

Our team specializes in masonry restoration for historic, commercial, and institutional buildings across Chicago and Northwest Indiana. Whether you’re planning repairs or conducting exploratory work, we’re here to help you design a solution that lasts.

Get in touch to schedule an inspection or request technical input on your next project.

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Brick wall with a window sill, featuring red-brown bricks and a vertical seam.

The Role of Expansion Joints in Preventing Spring Water Damage

By Peter Merlo • March 26, 2026

Spring water damage often gets blamed on cracks, failed mortar joints, or deteriorated sealants. In many cases, the real issue starts earlier, at expansion joints that were never designed, detailed, or maintained to manage seasonal movement. For commercial and multi-family buildings in Chicago, expansion joints are a primary defense against moisture intrusion during spring thaw. When they fail, water finds its way behind masonry, into wall assemblies, and down to steel and concrete elements that were never meant to stay wet.