Downtown Woodstock's historic square is home to some of the finest brick commercial buildings in McHenry County. When the owner of a 1910-era storefront building contacted RCC Masonry & Concrete, the building's exterior was showing serious signs of age — but the wrong repair approach would have done more damage than the deterioration itself.
The Challenge: 100+ Years of Weathering
The three-story building had deteriorated mortar joints across approximately 60% of the front and side facades. Previous patch repairs — done decades ago with modern Portland cement mortar — had actually caused worse damage. The hard modern mortar trapped moisture against the softer historic bricks, causing accelerated spalling around every patched area.
Additionally, the building's decorative brick corbeling (stepped-out courses) at the roofline had several loose sections, and the stone window sills showed significant erosion. The owner wanted a restoration that honored the building's character, not a quick patch job.
Project Overview
Our Approach: Traditional Techniques for Historic Masonry
The key to this project was mortar selection. We formulated a custom lime-based mortar (Type O) that matches the softness and flexibility of the original mortar. This is critical: the mortar in a masonry wall should always be the sacrificial element — softer than the bricks so it absorbs stress from thermal movement and moisture cycling. When hard modern mortar is used on soft old bricks, the bricks crack instead of the mortar.
Phase 1: Removing Failed Modern Patches
Before repointing, we carefully removed all previous Portland cement patches and repointing. This was painstaking work — the hard modern mortar had to be ground out without damaging the surrounding historic bricks. We used thin diamond blades and hand chisels, avoiding the aggressive grinding methods that would be acceptable on newer masonry.
Phase 2: Brick Replacement & Corbel Repair
Approximately 45 bricks needed replacement due to severe spalling. We sourced salvaged bricks from the same era — matching the size (which differs slightly from modern standard bricks), color, and texture. Each replacement brick was individually selected and positioned to blend seamlessly with the originals. The decorative corbeling at the roofline was stabilized with stainless steel pins and rebuilt where sections had become dangerously loose.
Phase 3: Full Repointing with Lime Mortar
With all joints cleared to a depth of 1 inch, we repointed the entire facade with our custom lime mortar, color-matched to the original warm gray tone. Each joint was tooled to a slightly concave profile matching the original joint style. Lime mortar takes longer to cure than Portland cement (28+ days vs 7 days), so we scheduled the work to allow adequate curing time before cold weather.
The Result
The building looks like it's been carefully maintained for the past century — which is exactly the goal of proper historic restoration. The new lime mortar will continue to cure and harden over the coming months, developing a natural patina that matches the aged brick. More importantly, the building is now protected from water infiltration while remaining breathable — no trapped moisture to cause future spalling.
Historic Masonry Needs Specialist Care
If you own a historic brick building in McHenry County or Lake County, don't let a contractor use modern Portland cement mortar for tuckpointing — it will cause more damage than it fixes. RCC Masonry & Concrete understands historic masonry and uses the right materials and techniques for buildings of every era. Call (224) 441-5284 for a consultation.