Building expansion joints are a necessity to accommodate differential movement between structures to prevent damage to both the structure, as well as building cladding and finish systems. Expansion joints within the realm of the building enclosure can be some of the most complicated detailing within a project; however, many times there is simply not enough information at the time the design documents are prepared to provide a completely integrated system. This is particularly true when a new structure is to be constructed adjacent to an existing structure where as-built conditions are not known. Further, multiple subcontractors/trades are often involved. How is an expansion joint concept turned into a constructable air, water-tight, thermal and fire-rated system that is both continuous at transitions, fully integrated with adjacent systems, and still accommodate necessary movement, sometimes in multiple directions? Additionally, who is responsible for taking the design concept to this level of detail; the design of record, the manufacturer, the contractor(s), the enclosure consultant, a collaboration of these entities?

Using two case studies this presentation will outline both challenges and solutions to tackling complex building expansion joints. With both case studies, the design documents provided only the expansion joint path and a general concept for detailing these joints. Details outlining the interface between horizontal and vertical joints, at inside and outside corners, and transitioning between materials require significant more in-depth analysis to achieve design objectives. This presentation will demonstrate the use of three-dimensional sketches and computer rendering to convey step-by-step installation at complex geometries and how these tools can assist with design team collaboration and conveying complex information to the installing contractor(s). The majority of the expansion joint design presented includes concepts that provide two lines of defense against water leakage and air infiltration and allows for drainage between the primary and secondary seals, as well as maintain the thermal and fire barrier. The presentation will include unique building products and methods for combining conventional materials to create successful transitions that also provide necessary movement capacity. The importance of mockups at difficult transitions to evaluation constructability and convey critical detailing objectives with the contractor will be highlighted. Finally, recommendations for developing and implementing a testing program to evaluate the air and water-tightness of installed expansion joints will be reviewed.

1. Discuss methods to integrate vertical and horizontal expansion joints constructed with different assemblies or materials.
2. Identify potential resources to assist in design and development of air and water-tight expansion joints.
3. Recognize critical areas of expansion joints that may require more in-depth analysis to achieve design objectives.
4. Develop a testing program for building expansion joints based on the needs of the project and complexity of the design.