b'Integral J-Channel InstallMost brands of uPvc replacement windows with mounting fins, are available with an integral J-Channel (siding return) molded into the windowframe profile. These built-in J-Channels can bewide and decorative, others can be thinner. However,each variation serves the same purpose: to enable diversion of water from around the window withoutinstalling a separate J-Channel and/or drip cap.Installation of a window with a built-in J Channel is straightforward and can be done with either theBarrier Method or Drainage Method of flashing.The diagrams here show Method B where flashingis first attached to the wall, then a second layer overthe fin, and optional building paper layer installedover the total wall, overlapping the flashing.The goal no matter which method is used is to properly overlap the flashing on the wall and finallyoverlap the second flashing layer over the mountingfin. In this way, water is directed around and downthe sides of the new window, properly draining andpreventing water intrusion.Remember: Do not seal the bottom fin to allow waterthat may enter or condense inside the opening, tohave a proper patch to drain and eventually dry.There are more than one style of Integral J-Channel frame profiles.Step 1: Step 2:Apply adhesive-backed Mount window usingflashing along sides nails along the jambsand bottom of opening. and Simplex-type cap nails along thetop to accommodateexpansion as shown.Place horizontalApply bead of bedding flashing over sealant on jamb flash- top of headering and along header nailing flange,to set the window. Do overlappingnot apply along sill. jamb flashing.Window Fitters Guide to Window Installation1012020 AWDI, LLC Do not reproduce without permission'