The Problem
The owner of this 1928 brick bungalow in Uptown Park Ridge was concerned about the limestone window surrounds. Mortar at the joint line between brick and limestone on the two front windows had cracked and pulled away, leaving visible gaps. The main brick joints on the front facade were also receded, with the north-facing side showing the most deterioration - typical of a home with mature trees that keep the north wall in shade and shade-damp longer through the winter.
A previous tuckpointing job on the rear of the house had used a standard pre-mixed mortar that was too hard for the limestone. Two of the limestone blocks on the rear showed hairline cracks at the joint line, which confirmed that the wrong mortar had been applied against the stone.
Our Solution
We addressed the brick and limestone joints differently, as they required different mortar compositions.
For the brick joints on the front facade and the north side wall - 175 linear feet total - we used a Type O lime-rich mix matched to the original 1928 mortar color. Joints were ground to 3/4 inch depth with a hand grinder and packed in two lifts. The original profile on this bungalow was a slightly weathered, nearly flush joint, which we replicated with a flat jointing tool.
For the limestone-to-brick transition joints at the window surrounds, we used a lean lime putty mortar without Portland content. This mortar is softer than the stone, which means any stress from seasonal movement is absorbed by the mortar joint rather than transmitted into the limestone face. These joints were filled in a single lift due to the narrow profile and struck flush.
The Result
The window surround joints are sealed without any hard mortar against the limestone. The brick joints on the front and north facades read consistently and match the color of the remaining original mortar in the protected interior joints. The owner appreciated that we called out the earlier incorrect repair on the rear elevation so they understood the risk and could plan to address it separately.
