Understanding how moisture intrusion and structural movement affect masonry walls—and how engineered repairs restore stability.

If you work on older brick buildings, you’ve seen it—a wall that’s no longer straight.

It leans outward. Mortar joints crack. Doors and windows begin to bind.

At first glance, it may appear cosmetic. In most cases, it is not.

Bowing masonry walls are typically the result of long-term structural movement combined with moisture intrusion. Left unaddressed, the condition will continue to progress.

How Older Brick Buildings Are Constructed

Many older masonry structures are built with two layers of brick.

• Interior wythe: structural layer supporting floor joists
• Exterior wythe: outer layer acting as the building envelope

The exterior wall must be maintained. When it is not, water enters and becomes trapped between these layers, leading to deterioration of both masonry and structural components.

How Water Intrusion Leads to Structural Movement

• Mortar breakdown allows water entry
• Moisture becomes trapped within the wall assembly
• Brick begins to weaken
• Steel lintels corrode and expand
• Wood framing begins to deteriorate

Over time, this process reduces structural integrity and contributes to outward wall movement.

Project Example: Philadelphia Rowhouse

The following project illustrates how moisture intrusion and structural movement often work together in older masonry buildings—and how both must be addressed to achieve a lasting repair.

The Problem

As the interior support weakened, floor joists lost bearing and sagged approximately 3.5 inches across the span.

These unsupported joists began exerting outward pressure on the exterior wall, contributing directly to the bowing condition.

The Structural Repair

• Sistering of floor joists to restore structural capacity
• Reconstruction of interior masonry support
• Lifting and leveling of the floor system
• Installation of through-wall structural rods

Structural Star Bolts

Structural star bolts are used to stabilize masonry walls by tying the exterior wall back into the structure and distributing load across the brick surface.

• Steel rod runs through the wall
• Anchors into structural framing
• Exterior plate distributes load
• System is tensioned to stabilize movement

Engineering and Oversight

• Structural engineering design and review
• Multiple site inspections
• Permit approvals
• City inspections

Final Observations

Bowing brick walls in older buildings are rarely caused by a single issue. Structural movement and moisture intrusion are often directly connected.

Effective repair requires addressing both the structural condition and the source of deterioration. When properly engineered and executed, these systems provide long-term stabilization.

A version of this project breakdown is also available here: View LinkedIn Article

Bowing Brick Wall Repair Services in New Jersey & Pennsylvania

Structural wall movement and moisture-related issues are common across many areas we service. Our work includes projects throughout:

• Mercer County, NJ
• Middlesex County, NJ
• Monmouth County, NJ
• Bucks County, PA
• Philadelphia, PA