A new guide published by APA – The Engineered Wood Association describes how builders can increase the structural and energy performance of a home with a raised-heel truss construction system. Building with raised-heel trusses results in both savings for the builder and an energy-efficient, structurally superior residence for the homeowner.
A raised-heel truss is identical to a conventional truss except that it is raised higher, with a “heel” that extends up from the top of the wall and elevates the truss at the building’s edges. Raising the truss higher has two big advantages over typical truss construction: it simplifies attic ventilation and it leaves ample room for insulation above exterior wall top plates. With the added space, the truss doesn’t compress attic insulation over the top plate and compromise its insulation value, a common weakness of conventional truss systems.
The energy code allows for use of less insulation for the entire ceiling system when a raised-heel truss system is used, allowing builders to reduce material costs while increasing energy efficiency. Home Energy Rating (HERS) studies also indicate that with consistent ceiling insulation, the home maintains a more stable interior temperature that results in a noticeably more comfortable home, as well as lower utility bills.
The system also features structural advantages, according to APA. Wall systems that combine raised-heel trusses with overlapping continuous plywood or oriented strand board (OSB) sheathing have better resistance to lateral forces, such as high winds or seismic activity, than those fastened with conventional wall-to-truss connections.
Key components of the raised-heel truss system are described in the new guide, Raised-Heel Trusses for Efficient, Cost Effective, Comfortable Homes, Form R330. The guide is available for free download from the APA website at www.apawood.org/raised-heel-trusses. Printed copies of the guide are also available for $2 per copy and can be ordered through the website.