Liberty Pet Door For Doors (Double Flap) - Installation Instructions

Installation Instructions

Double Flap Door Mount Instructions

installation video image
Installation icon Difficulty High
Installation icon Steps 11
Installation icon Time Required 2-3 hours
Installation icon Sections 06
Installation icon Flags 03


  • 1 Installation Template
  • Short Screws (2-1/4")
  • Long Screws (2-3/4")
  • 4 Screw Covers
  • 1 Installation Magnet
  • Outside & Inside Flap Frames
  • 1 Sill Plate
  • 1 Tube of Silicone
  • 1 Locking Cover


  • Pencil
  • Drill with 3/8" (9,5 mm) drill bit
  • Level
  • Measuring Tape
  • Jigsaw or Reciprocating Saw

Please read instructions & notes thoroughly before installation.

Double Flap Door Mount

Step 1 Prep Your Door

  • If you have not yet measured your pet, review this guide to ensure the pet door will work.
  • If possible, remove the door from its hinges using a screwdriver and hammer to tap out the hinge pins. Lay the door flap for installation. Tape the provided template to the door. The top edge of the cut-out line should be at least 3” (7,6 cm) above the pet's shoulders.
  • Be careful not to cut too close to the bottom of the door as you may reduce the door's strength. Level the top edge of the cut-out line.

Step 2 Drill the Holes

  • Once you are certain the pet door will work with your door, make sure the template is level, and mark the outline with a pencil. Remove the template and drill holes through the corners just inside of the lines using a ⅜” (9,5 mm) drill bit.
  • Make sure your drill is kept level and drills all the way through the door.

Step 3 Saw An Opening

  • Using a jigsaw, cut along the marked lines, making sure to cut straight.
  • We recommend applying masking tape along the outside of the lines to protect your door from scratch marks as you cut with the jigsaw.

Step 4 Place Sill Plate

  • Ensure the weather-stripping is firmly pressed in the groove on both frames. Weather-stripping indicated in red.
  • Depending on your door model, you may have a sill plate. Rest the sill plate at the bottom of the cutout with the weather stripping facing up and the outer leg on the outside of the door.

Step 5 Caulk U Shape Tunnel

  • Apply caulking to seal the tunnel to the inside frame.

Step 6 Check Weatherstripping

  • Ensure the weatherstripping is firmly pressed in the groove on both frames. Weatherstripping ends on the side for the inside frame, while the outside frame has an open area at the bottom to allow water to flow outside down the sill plate. Weatherstripping is indicated in red.

Step 7 Position the Frames

  • Place the inside frame with the tunnel on the inside of the door just resting on top of the sill plate weatherstripping. Take the exterior frame and place it on the outside of the door fitting inside the tunnel.

Step 8 Position Screws

  • Select appropriate screws and insert them into the pet door from the inside.
  • Do not fully tighten screws until all four screws are inserted and the pet door is leveled.
  • Use the included installation magnet to help align the screws.

Door Width Screw Length
1-⅜” (3.5 cm) Short Screws (1-¾”)
1-¾” (4.4 cm) Long Screws (2-¼”)

Step 9 Screw Door Into Place

  • Once the pet door is leveled, tighten the screws so that the weatherstripping compresses.
  • Do not overtighten.

Step 10 Attach Screw Covers

  • Push the four screw covers in by hand to cover the screws.
  • If need be, use the wooden end of a hammer rubber, or other non-metal tool to tap in the hole plugs. You can also place a wood block on the hole plug and tap the block with a hammer.

Step11 Seal With Silicone

  • Apply silicone where the two frames meet. Also apply silicone where the outside frame meets the door.


The best way to install the pet door is to have it straddle the recessed area of one of the panels. Have the pet door sit on the flat area in the middle, side, and below the recessed panel. The frame will cross the recessed area on the top, so you will be left with a gap. The easiest way to fill this gap is to get battens or shims from a local hardware store, and cut them to fit.

When that gap is mostly filled, caulk the remaining areas to seal the doggy door to the surface of the people door. If the space is very irregular you can also use a squishy foam weather stripping, which will compress down for a tight fit. When finished, use caulking to seal the door.