Understand the Probem: Conventional roof trusses have top chords that rest close to the wall plate, compressing the insulation at the building’s perimeter and creating an underinsulated cold spot.
Allow for R-Value: How high a heel? That depends on the insulation needs. In some climates, code-compliant houses may need room for 10 inches of insulation or more. For beyond-code, super-insulated homes, builders may want to pile insulation 2 feet or 3 feet deep.
Protect from Wind-Washing: In vented roofs, airflow through the vents can diminish the heat-trapping effect of insulation. Be sure to install baffles at the eaves to direct the flowing air into the attic, but not through the loose fiber.
Brace for Loads and Codes: Tall trusses may topple, so pay attention to the bracing. In high-wind or seismic areas, raised-heel trusses need special blocking and connectors. And even in a zone with no extra lateral loads, the code’s “braced wall” rules will govern how the truss is attached and braced. Your truss supplier’s engineers should specify the connections; your job is to follow their directions.