Start by placing flange first on head, then jambs and end at window sill. The nailing flange on a new-construction window is that metal or plastic apron-like piece that extends outward to let you nail the window against the house. It's how windows are meant to be installed. House wrap should go over top of the membrane. Re: How To Install a Window with a Nailing Flange Post by Shannon » Thu Nov 16, 2017 6:24 pm yup those are the types of products you need ,defiantly not paint primer. Also called nail fin. For the love of god, go with flange install. A … pre-cutting full window width at 45°. Reinforce corners with provided glue. Add the last piece of the membrane along the top of the window. I think it has been pretty well established through this thread that many (not all!) Take the tube of caulk, and spread a few beads between the nailing flange and the sheath. I think this is a much better solution than hanging the window away from the framing whether backed by plywood or just foam, particularly if you are using something like Zip sheathing which relies on its tape to lap over the nailing flange to establish a reliable water shedding assembly. feel that the reason for not nailing the top flange is that the top needs to be 'open' and not be 'forced' down with 'settling' as the new wood shifts and adjusts. Nailing fin — An independent accessory that attaches to a window jamb to help ensure window is installed properly, and will resist bowing and warping over time. Step 3: Snap-in flange on exterior groove of window frame. Add the window membrane to the sides. Finish installing the window by nailing the flange all the way around. Also called nail fin. Be sure to overlap the flange to cover the nails. The only situations in which a window should be installed without a flange are 1. replacing wooden sash windows with vinyl or 2. situations where the siding can't be easily cut, such as brick. How to Install a Replacement Window – Pella Series 20 from Lowes Home Improvement How To Install a Window with a Nailing Flange How to protect yourself from hurricane product fraud If the flange is nailed the top of the window would be pushed down with this settling. Note that replacement windows will not have a nailing flange; only new-construction windows will have this nailing flange. Step 2 - Install a Window Once you have fitted the caulk, take your window, and place it into the opening. Head flange should extend full window width.