Header wraps are often used to provide continuity at the junction between wood framed floor systems and the concrete foundation wall.
Other systems for sealing this area include creating a structural air barrier by caulking the joints between framing members and the top of the foundation wall. Rigid polystyrene foam placed vertically between the foundation and the subfloor and caulked at both ends is a very popular approach in the atlantic provinces.
Finally, sprayfoam insulation applied to the rim joist cavity between the top of the foundation wall and subfloor will greatly reduce the amount of heat loss. These four systems are among the many, different approaches used by builders across the nation. Corners are always a challenge and require special care to ensure air barrier continuity.