What are Outriggers, and Why Do We Need Them?

 

As Matt Hoots of Sawhorse, Inc. and Chris Laumer-Giddens of LG Squared, Inc. explain in this video, outriggers are rafters or trusses that extend beyond the roof of the building. Outriggers create an overhang to protect everything below, especially for the upper half of the building, including siding, and windows.  Outriggers can also help manage solar gain. 

 

With deep window reveals, the outriggers at the #1920sMakeoverATL deep energy retrofit project are a bit more aesthetic, as this is a historic renovation where one goal is to bring back th home’s original look and respect the history, but they also provide back up, or a “belt and suspenders” for protecting the walls.  

 

Outriggers with continuous insulation prevent penetrations in the sheathing, which helps reduce the risk of air leakage and thermal bridging, and avoids interruptions in the insulation.  The result is a “clean intersection” with encapsulated sheathing to and down the wall. Structural insulation is preferable to foam and sealant as foam can delaminate or separate with future building expansion and contraction.  Likewise, sealant also dries and cracks.  Continuous insulation maintains the same temperature throughout, which means expansion and contraction will take place at the same rate. 

 

The outrigger is a simpler way to achieve the air barrier and provides more control.  Meanwhile the outrigger is the same thickness as a regular overhang, so there’s no design compromise.  Basically, you get the same look and eliminate “transition risk,” which is where different materials come together, and also where there’s often the greatest risk for air, water, vapor, and energy leakage.  

 

Do you have questions for Matt and Chris? Do you have additional information to share about outriggers? Reply below and share your thoughts!