StyleGuard® Flange Double Hung Window Installation Instructions

For Double-Hung Windows with Flange (Also similar instructions for StyleGuard® Fixed Windows with Flange)




STEP 1: Prepare the Opening

Note: Installation of fixed picture windows with nail fins is the same as that for double hung, except for operation of moveable window sashes that are not on fixed windows.

  • Ensure the rough opening is 1/2” larger than the window to be installed and that the rough opening is plumb and square. See Detail 1.

Note: The frame size of the window does not include any protruding nail fins.

  • Close and and lock the sash(es) to help keep the unit square.
  • Place the sill anchor plate on the pre-cast sill, and position it approximately 5/16” back from the outside edge of the buck. Shim to level if necessary and secure the sill anchor plate to the pre-cast sill with #10 x 2” Tapcon® masonry fasteners. See Detail 2.
  • Run a bead of silicone caulk on the outside surface of the wood buck and pre-cast sill where the window flange will
    make contact as shown in Detail 2.

STEP 2: Install the Window

  • Set the window into the opening from the outside so that the flange makes contact with the outside surface of the wood buck and pre-cast sill. See Detail 3. Make sure the sill anchor plate interlocks with the bottom of the window to assure integrity of the sill under negative and positive pressure. See Detail 4.

  • Center the window in the opening and check to make sure it is plumb and square. Take diagonal measurements to ensure the unit is square. Opening the bottom sash of the double hung window approximately 1/4” will provide visual confirmation of proper setting, that the reveal between the frame and sash (A & B) are equal the entire width. See Detail 5.

  • Shim as required between the rough opening and the window frame at pre-punched installation hole locations.
  • Secure the window in the opening through the pre-drilled holes in the head and jambs using Tapcon® masonry fasteners. To access the installation screw holes, use a putty knife to remove the snap-in cover or screw track cover as shown in Details 6 and 7. Replace the covers after the screws are set. All fasteners must have a minimum 1-1/2” penetration into the masonry.

STEP 3: Finishing

  • From the exterior, caulk along the flange of the window to ensure a watertight seal as shown in Details 6 and 7.
  • Operate the window (for double hung) to confirm proper installation.
  • Apply fiberglass insulation to the cavity between the window and rough opening structure.


  • Do not use expanding or spray-in foam products. If the installer used one of them, make sure jambs remain straight to ensure the operation of the window is not impeded.
  • If using brick or stone exteriors, leave a 1/8” gap from the window to allow for brick and mortar expansion. Use a backer rod and silicone caulk to seal the gap.
  • Do not use brick wash after windows are installed. Doing so will void the window warranty.
  • Windows should never be stored in an area where temperatures will exceed 140° F. Doing so will void the window warranty.
  • Windows should never be painted. Doing so will void the window warranty.

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