and Doors At window and doors, cut the panels (if necessary) to fit the openings, allowing 1/4" for expansion. If the panel is uncut or cut down in the "V"- shaped groove of a piece of vertical siding, simply insert it into the J-channel, locking the other side onto the previously applied panel. A furring strip should be installed to prevent panel detachment. If the panel is cut on the flat surface, install undersill trim, backed by furring, into the J-channel. The flat surface of the vertical siding should be snap lock punched and fitted into the undersill trim. The panel is further secured above and below the windows and above the door when the panel is fastened in place. Corners Install the undersill trim or J-channel into the receiver of the corner post. If the panel is cut in the bottom of the V-groove, insert it into the J-channel. A furring strip should be provided prior to panel insertion. This will prevent the panel from detaching. If the panel is cut on the flat surface, install undersill trim, backed by furring, into the J-channel. Punch snap locks along the cut edge of the panel at 6" intervals and snap it into the undersill trim. Gable Ends Begin by fastening J-channel along the inside edge of the roof. Install vertical base on top of previously installed J-channel at the base of the gable. Attach either vertical siding starter strip or two back-to-back regular starter strips, centered with the peak of