The Problem
A spring hailstorm with documented quarter-size hail moved through the East Glencoe lakefront corridor in late April 2022. The homeowners of a 1928 Tudor Revival noticed the damage two years later when limestone panels above three first-floor windows began dropping thin flakes onto the window ledges below. By the time we assessed the property, the spandrel panels showed surface spalling across roughly 40 percent of their face area, and two of the Indiana limestone window sills had developed hairline cracks running parallel to the stone bed. The mortar joints along the limestone string course were also open at several locations where differential movement between the limestone trim and the surrounding brick had widened old joint failures.
Our Solution
We began with a tap survey of all limestone elements on the front facade, mapping hollow sections with chalk to define the full extent of friable material before any cutting began. Two of the three spandrel panels had sound substrate under the spalled face. The third had a 6-inch section of through-delamination that required a consolidant injection before any repair mortar could bond.
For the sound panels, we applied a penetrating consolidant to stabilize the friable zone, then built back the profile in two stages using an NHL 2-based repair mortar tinted with iron oxide pigment to match the warm gray of the original Indiana limestone. Each stage was allowed to reach initial set before the next layer was applied. The maximum build depth per lift was 3/8 inch to prevent shrinkage cracking.
The open joints along the string course and entry surround were raked to 3/4-inch depth and repointed with NHL 2 mortar matched to the original joint profile. At the brick-to-limestone transition courses, we used a slightly softer mix to account for the differential movement between the two materials. All repair mortar was kept back from the stone face by 1/16 inch and finished flush after initial cure.
The Result
The spandrel panels returned to a consistent flat face with no visible shadow lines at repair boundaries. Mortar color at the string course reads within one shade of the original joints in protected areas. The through-delaminated section on the third panel consolidated fully and accepted the repair mortar without rebonding issues. We recommended the homeowners document this repair with their insurance carrier given the confirmed hail event date, which they subsequently pursued.
Related: Limestone Restoration Services | Glencoe Service Area
