b'If the decision is to leave the old frame intact, and If there are no weep holes inmount the new window to it or over it, then the the left-in-place sill track, drillpreparation of the old frame should include provision at least two to allow trappedfor drainage, as previously described. water to drain to the outside.If the old frame is wood,The installed window shouldthen application of liquid have a flush frontal fin to over-flashing can be made to the lap the siding while the frame Goodremaining sill, painting it of the new window rests on thealong the bottom and up 4 left-in-place frame of the oldto 6 on each side. Apply the window. Installing mountingliquid so as to seal all joints blocks in the channels of theof the sill to the interior stool, old sill will help support andand to the jambs on each level the new window. side. This will keep water If the total frame is to bethat may collect under the removed, start by cutting new window from being back the siding to expose theabsorbed into the old wood old mounting fin. This willframe. allow the fasteners to be BetterFurther, application ofremoved from the fin, openingadhesive-backed flashing to the cavity to re-installation of the jambs and header will a finned window. Molding isprovide a diversion path for then re-installed, with appro-any water that comes into priate drip cap and flashing, the cavity. The adhesive- to mate up with the cut-backbacked flashing should be siding simulating brickmoldapplied to overlap the liquid- trim, as shown. Bestapplied sill flashing. If the new window frame isCutting deeper than the old frame,When the new window is Back then the new window needs tomounted, be sure that any to the be smaller in width and height to sit inside the left-sill angles or starter strips fin in-place wallboard and stool, as shown. An alterna-allow weeping of anytive is to kerf a groove in the brick mold to fit overcollected water out from the nailing fin whichunder the new windowswill offset the new win-sill. If the sill is capped, do dow towards the exteri-not caulk the underside to or so the interior face ofprevent trapping of water or the frame can sit in the Use pvccondensation under the sill same space as the old trim boardscapping.frame allowing the maximum width and height of thenew window, as shown. It is also recommended thatFor aluminum windows,where the mounting fin is a waterproof trim be used. under the siding (stucco or Important considerations are required whenother siding), you canleaving the old nail fin in place. See Page 44remove the existing windows for Guidance.operating sash, and then the stationary glass panel.Cutting the bar between thesash and glazing panelsRemovecreates an unobstructed the whole opening, leaving the old sill, windowheader and jambs in place.As before, use liquid applied Thepiecesflashing. The sill should be left cancoated, carefully sealing the make ajoints between the sill and The pieces leftwaterthe jambs. Apply the liquid can make water pathpath atup each side 4 to 6. at header and jambs. the sill.Window Fitters Guide to Window Installation372020 AWDI, LLC Do not reproduce without permission'