Tension Lock System
Trillium Dell’s unique Tension Lock System is a cost-effective and non-invasive means of restoring the structural integrity of failed tension members. Approximately eighty percent of the barns and other timber frame structures we routinely assess have tension failures. These failures occur most often between the tie beams and posts due to failing foundations and roofs. This failure occurs when the tenon fails, allowing the joint to separate.
Traditionally, metal stirrup straps or other types of metal bracketry have been used to anticipate or stem this problem, rather than more labor intensive alternatives of employing wood to wood joinery in situ. The Tension Lock System mimics and improves this traditional precedent. Two round, cast iron discs grip the disconnected members. Once the failed tension member is pulled back together, these two discs are connected with a steel strap and two lag bolts, which looks nearly the same as a traditional metal bracketry repair. Importantly, the cast iron discs - and not through bolts - grip the timber face and hold the tension. Many repairs installed without these tension disks fail because the tension is held by the bolts alone, introducing a sheer plane upon which the timber splits.
While these repairs cannot overcome neglect, many historic timber frame structures could be saved using this low-budget restoration technique. The Tension Lock System is just one way Trillium Dell Timberworks works to save historic structures using common sense approaches within customers’ budgets.