THE CHALLENGE
75 Kneeland Street (the Hudson Building) is a 14-story building located in the Chinatown neighborhood of Boston. Each precast panel on the façade was deteriorating as a result of freeze/thaw weathering resulting from lack of air entrainment. Over the last 40 years the building had undergone a number of attempts to address the deterioration, however, in general, the repairs were mostly cosmetic and did not address the root cause of the deterioration.
CBI’S SOLUTION
CBI performed three services for this project; we provided engineering to assist with the shoring needs to remove/secure large concrete pieces being repaired, we performed onsite investigations from a 180 foot boom lift and binoculars from street level, and the third effort was to explore alternatives for façade restorations.
Prior coating applied to mask deterioration was accelerating the failure. Lack of flashing was also contributing to the deterioration because of the oxidation of steel lintels and leakage to the interior. Deterioration of the precast was mostly concentrated at the 14th and 15th floors and consisted of three general types; cracked/spalled precast, soft mortar joints, and displacement of the veneer. CBI removed the brick above the 15th floor at the parapet, designed and applied a new flashing system between the window head and coping and applied a flashing system made of elastomeric sheet goods and mastic.
Studies were conducted to consider the most reasonable replacement for the art deco including glass fiber reinforced plastic (GFRP). Without having a historical designation, comparisons were made with brick and EIFS replacements. Although, significantly more costly and time consuming, the Owners chose a full detail replication in precast concrete. There was extensive pre-planning and major efforts to make sure the existing art deco pieces were identically replicated.
