2. Connect the sill flashing to a through cavity flashing component that is sloped to the exterior and directed over the cavity between the frame and the exterior cladding. The key difference from existing sill pan systems is the drainage component of the flashing is directed to the exterior of the cladding rather than behind the wall.
3. Apply a robust interior air and water seal through the use of sealant or low-expansion foam around the entire interior perimeter of the window to prevent air and water intrusion to the building interior.
These steps will better align the replacement window installation with the water-management installation principles for new construction and will go a long way to improving the moisture protection of the building envelope when replacement windows are installed.
Alan Hubbell is residential marketing manager, DuPont Building Innovations; Jim Katsaros is the building envelope integration champion for DuPont Building Innovations.