The Problem
The homeowner noticed mortar crumbling along the entire north and west facades of their 1938 Georgian Colonial near Sheridan Road. Years of direct Lake Michigan exposure had taken a heavy toll. Mortar joints on the north face were recessed over 3/4 inch deep, and several joints on the west side had lost mortar entirely, leaving open gaps where water could enter the wall cavity freely.
A previous contractor had patched sections of the east wall with Portland-heavy Type S mortar roughly ten years prior. That patch was already cracking and had caused spalling on adjacent soft brick - a textbook example of why mortar type matters on pre-war homes.
Our Solution
We removed deteriorated mortar to a uniform depth of 3/4 inch across all four facades using hand grinders with diamond blades set to the correct depth. No rotary saws - the original brick on this home is soft Chicago common brick that chips easily under aggressive cutting.
The replacement mortar was a custom-blended Type N lime-based mix matched to the original 1938 mortar composition. We pulled mortar samples from a protected interior joint to get the original sand color and aggregate size right. The final blend used natural sand from a local quarry to match the warm tan tone of the original joints.
All 280 linear feet were packed in two lifts (layers) per joint - the first lift filled to half depth, allowed to firm up, then the second lift brought the joint flush. Each joint was tooled with a concave jointer to match the original profile. This two-lift method ensures full bond strength and eliminates the voids that cause premature joint failure.
The Result
The completed tuckpointing restored the facade to its original 1938 appearance. Mortar color matches within a shade of the original joints in protected areas. The previous Type S patch on the east wall was removed and replaced with correct Type N mortar to stop further brick spalling.
We documented the mortar formula used so future repairs can match exactly.
