100 Year Old Church Uses New Technology to Revive Windows

After 100 years of serving as a place of worship and community, St. Mary’s Catholic Church in Potsdam, NY, needed a renovation. The intention was to refurbish and reglaze only the stained glass, including the 23-foot-high Gothic unit with the Rose Window above the main entrance. However, it was discovered that the windows were badly deteriorated, and a new plan was required.

In 2010, stained glass was carefully removed from the original windows, and Marvin replicated the frames of the 15 Gothic Revival windows, including the 15' x 23' Rose Window prominently displayed on the church’s facade. The windows, originally built in three layers of old-growth pine, were replicated with six layers of Honduran Mahogany With staggered finger joints for a strong and layered profile. The Rose Window consisted of 816 individual pieces, each engineered to micro-accuracy to accommodate reglazing.

After more than a century of weathering, shifting and settling, no two openings were alike, so a variety of state-of-the-art digital measuring techniques were used to create a precise fit — as well as full-size frame rubbings and glass tracings. Measurements for each new window needed to be exact to accommodate fixed stone and glass dimensions. To achieve these exacting measurements, Jerry MacNeil Architects Limited employed tacheometric survey software in combination with rectified photography to capture measurements digitally. BIM and CAD/CAM technology, cyber models, and cutter designs downloaded directly to Marvin’s CNC equipment allowed window fabrication to be a paperless process.

With an intense spirit of collaboration and a project filled with pride, the workers performed a carpentry tradition well-known in European history — each worker signed the concealed edge of the Rose Window before its installation.


Architect: Jerry MacNeil Architects Ltd.

Contractor: J.T. Erectors