Church of the Immaculate Conception

Roof Structure Evaluation
Boston, Massachusetts

Constructed in the 1860s, the slate roof of the Church of the Immaculate Conception is supported by a structure of dimensional lumber roof framing supported by a series of heavy timber scissor trusses spanning the width of the church. Within the church nave, two lines of timber frames and columns support the roof scissor trusses. These trusses and frames used traditional construction methods, mortise and tendon wood joints secured with wood pegs. Gale evaluated the roof structure to determine the condition of all framing elements and to identify any observed deficiencies or damage. We also performed a series of structural analyses on the framing systems to determine the capacity of the roof framing system in its present condition. These analyses were also used to determine the extent of deficient framing when modern building load conditions were applied.