The strapped cavity wall assembly shown in this detail creates an air space between the siding and the sheathing paper to facilitate drainage and drying of rain that penetrates past the wood siding. This approach to water penetration control is commonly referred to as a 'rainscreen' approach. The window placement in the wall assembly also provides a second line of defence with respect to the water penetration resistance of the window through the use of a self-adhesive membrane to provide sub-sill drainage.