Masonry Repair - Norridge, IL

Masonry Repair - 1955 Concrete and Brick Retaining Wall

April 6, 2026 | near Forest Preserve Drive

Before

After

Location Norridge, IL

Service Masonry Repair

Scope 14-foot center section rebuilt, French drain installed, full wall repointed

Mortar Type Type S

Duration 5 days

Building 1955 concrete and brick retaining wall

The Problem

The owner of a Central Norridge home noticed the center section of their rear yard retaining wall had shifted visibly. The 1955 wall - a combination of poured concrete base with three courses of brick above grade - had bowed approximately 2.5 inches outward at the midpoint of its 22-foot run. Two vertical cracks ran from the top course down to the concrete base, and the mortar joints along the bottom course had been pushed open by root and frost pressure.

The wall had no drainage behind it. The original contractor had backfilled directly against the brick with compacted soil. After 70 years of water accumulation, the hydrostatic pressure behind the center section had exceeded what the original mortar bond could hold. The bowing and cracking were both symptoms of the same underlying problem.

Our Solution

The 14-foot center section, which included the most severe bowing, was demolished completely. The end sections, which were plumb and showed only surface mortar deterioration, were kept in place and the new center section was tied into them with stainless steel horizontal joint reinforcement.

Before rebuilding, we excavated 18 inches behind the demolished section and installed a French drain: 4-inch perforated pipe set in a bed of washed #57 gravel, wrapped in filter fabric to prevent soil migration into the gravel bed, and daylit to the rear corner of the property. The drain runs the full 14-foot length of the rebuilt section.

The new brick was set in Type S mortar - the correct specification for a retaining wall, which requires resistance to lateral load rather than the flexibility-focused properties of Type N. Weep holes were installed at 4-foot intervals along the base course. The remaining original sections on each end were repointed with Type S mortar to match.

The Result

The rebuilt center section is plumb and tied into the original end sections with mechanical reinforcement. The French drain and weep holes give water a path out, eliminating the pressure that caused the original failure. The full wall surface was repointed in matching gray Type S mortar.

Questions About This Project

Why do brick retaining walls bow outward and crack over time?

Brick retaining walls hold back soil that is frequently saturated with water. When there is no drainage system behind the wall, water pressure builds against the back face - a force called hydrostatic pressure. That pressure increases significantly after heavy rain or snowmelt. Without weep holes or a French drain to relieve the pressure, the wall eventually deflects forward. Once the mortar cracks open under the lateral load, the cracking typically accelerates through subsequent freeze-thaw cycles.

When is a bowed retaining wall repairable versus requiring a full tear-down?

A wall that has deflected less than 1 inch and shows only surface cracking in the mortar can sometimes be reinforced and repointed. Once deflection reaches 2 inches or more, or once vertical cracks have opened through the full wall thickness, the structural integrity of the brick-mortar bond is compromised and the affected section needs to come down. Attempting to straighten a significantly bowed masonry wall without rebuilding it is a temporary fix that typically fails within a few years.

What drainage is installed behind a rebuilt retaining wall to prevent recurrence?

We install a French drain system directly behind the new wall: a 4-inch perforated PVC pipe set in washed gravel, running along the full wall length, and daylit to a downhill outlet or swale. We also install weep holes through the base course of the brick at 4-foot intervals to allow any water that builds up to drain forward through the wall face rather than build pressure behind it. These two systems together eliminate the hydrostatic pressure that causes the original failure.