Hall House Kitchen Rafter Consolidation & Repair
Salisbury, NC: 2005
During a series of repairs to the 1820s free-standing kitchen at the Josephus Hall House in Salisbury, NC, the owner wanted the local carpentry crew to receive training in the use of consolidants for in-place conservation of deteriorated structural members. Beginning with the triage process to group similar repairs, the carpenters worked with conservators on the full range of repairs necessary to address deterioration at the intersection of ceiling joists and rafters on the overhanging roof.
Most of these carpenters had some experience with epoxies, but not as a penetrating consolidant. Training was made more challenging by the 100-degree summer temperatures which was speeding up the cure rate of the epoxy, compromising the epoxy's strength and ability to penetrate. While the problems relating to epoxy formulations and temperature were nothing new, the project did incorporate a modern roofing material in a unique way to assist in the triage process. This integration of new materials to assist in saving historic buildings is one of the things that makes this work so interesting. And TPO definitely proved itself as yet another instrument in the conservator's toolbox.
In order to consolidate timbers in mid-air, everything from metal containers to EPDM bags had been used to hold the epoxy. Metal boots were reusable, but expensive and time-consuming to make. EPDM was quick to fit, but sagged. TPO on the other hand, was fiber-reinforced on a grid and thus relatively rigid and, because it could be easily cut and quickly welded using a high-temperature heat gun, it allowed the creation of tight-fitting boots that could be re-used from one rafter to the next.
Once the timbers were consolidated, the crew was shown how to quickly make wooden extensions to fit what remained of deteriorated rafter and joist ends using paper templates and a jigsaw. Creating custom-fit dutchmen for consolidated timber ends saved considerably more original building fabric than cutting back timbers to sound material and sistering on new timbers would have. By organizing the work, batching similar repairs, and using a toolkit that included penetrating epoxies and TPO for boots as well as common carpentry tools, these preservation-minded repairs were fast and cost-effective.