b'window and into the interior. Second, no moistureshall enter the cavity where it can condense andbecome trapped.All gaps over 1/8 that are sealed with caulk, mustuse backer rod. All gaps over must be covered withtrim, or any means to block water penetration intothe opening.The preferred method for trim/sealing the interiorand exterior is Snap Trim.Pvc windows are fittedwith an accessory groove into which trim can snapthat will bridge any gap, and maintain drainage out of the cavity and away from the window as shown.Aluminum windows can utilize two piece aluminumsnap trim, where one piece is screw anchored to theframe, and the finish piece is snapped in place toeffect a complete trim cover of the perimeter joint.All snap trim is cut to where the header portion passes over the top edge of side pieces, and where the bottom piece fits between the 2 side pieces. This effects the proper shingle-style overlapdrainage.Exterior joints can be caulked, interior joints are bestleft un-caulked to maintain vapor barrier continuityin warm/humid coastal areas.AlterativeUsing snap-in trimnew windows can be mountedeasily - especially with pre-formedIf the stucco is damaged, the new installation will require a lot cast sills.of repair as shown. Be careful, put in new bucks, and you canminimize the problem, and comply with code.How to Finish the InstallationIt is important to seal the new window in the openingto direct any water away from the interior and intothe drainage system of the wall. That is usuallybehind the stucco, and down to the bottom weepwithin the wall.Two goals must be met. First, no water that entersthe installed window cavity should get behind theWindow Fitters Guide to Window Installation1372020 AWDI, LLC Do not reproduce without permission'