On Monday, October 9th, scaffolding came down from St. Norbert’s Catholic Church after completely enclosing the tower and spire for five months. This followed an extensive restoration effort by masons, sheet metal workers, roofers, and window restoration specialists to stabilize and restore the 130 year-old tower and ensure its preservation for another century.
Through our relationship with the Diocese of Madison, Wisconsin, BEPG was engaged by the church in 2017 to complete a building envelope assessment of the entire church. Amongst other concerns, the church reported that they had been experiencing masonry falling from the tower, leading to life-safety fears for parishioners entering the church through the tower. BEPG quickly moved to have a protective canopy installed at the primary entrance of the tower while further inspection was completed. Upon further inspection by BEPG staff, severe deterioration of the stone and mortar was discovered, necessitating a substantial masonry restoration effort.
Quarried from a nearby quarry in the hills surrounding Roxbury, the stone used for both the 1860s church building and 1890s tower is a tan and orange-hued limestone with lots of color and texture differentiation, giving the church an incredibly unique visual character. Many of the buildings in the immediate and surrounding areas use the same limestone. In fact, at the time the church and tower were built, Wisconsin was the 12th largest supplier of stone in the country, becoming a major stone supplier to Chicago following the great fire of 1871.
BEPG’s primary goal for the church’s restoration was to preserve as much of the building’s original character, including keeping as much of the original stone in place as possible. Along with the mason, our staff thoroughly surveyed the entire tower to determine what stone restoration work was required. Where necessary, stones were removed and replaced, with the stone tooled to fit with the surrounding masonry as seamlessly as possible.
Finding a good match for the stone was difficult, as the original quarry was closed decades ago, and no local quarries provided a good match. The search was further complicated by the textural complexity of the original stone, as well as the different cuts of stone, including both textured and smooth stones. With the help of the masonry subcontractor, an excellent match was found at a Milwaukee supplier, who supplied all the replacement stone for the rehabilitation work.
Where stones were deteriorated but salvageable, loose stone was removed and a potassium-silicate stone consolidant was used. The waterborne treatment saturates and reacts with the stone, producing a strong but invisible crystalline bond. This process provides structural stability to minor delaminations and pores in the stone without damaging or changing the visual character of the stone.
Identifying a suitable mortar was just as important as finding a matching stone. The original mortar was a white-colored mortar, though much of this mortar is now tinged with tan due to leaching from the stone. Additionally, over 150-plus years, many pointing repair efforts had been undertaken, using unsympathetic mortar colors and compositions. Mortar samples were taken from the building and sent to an independent petrographic lab for analysis. The lab returned recommendations for the composition of the replacement mortar, including a primarily lime-based mixture rather than the common portland cement mortars used in modern masonry work. If an overly hard mortar (such as a Type O mortar) was used to repoint the building, it would eventually lead to accelerated deterioration of the limestone. Based on these recommendations, BEPG specified a Pozzolan Hydraulic Lime (PHL) repointing mortar, with aggregate mixture and sizing to best compliment the color of the stone.
BEPG is thrilled with the results of the masonry restoration efforts at St. Norbert’s Church. In addition to masonry work, the tower restoration included structural repairs and stabilization, as well as full slate reroofing and stainless steel trim.