How to Install a Cat Flap

When installing a cat flap, first consider the cat. Pet doors come in several sizes, so make sure the door is not too small for the cat to use. If the cat is not an adult, choose a door that the cat will not outgrow. Most large pet doors can accommodate a pet of up to 30 pounds. If there are larger pets in the house with restricted outside or room to room access, the pet door should be large enough only for the cat.
Pet doors may have manual, magnetic or infrared locks. Locks can be helpful when restricting the cat's movement. Magnetic and infrared locks come with a key that can be attached to the cat's collar. Sensors or magnets in the pet door unlock only for the pet wearing the collar key. This prevents strays from entering the home.

Things You'll Need

  • Square or ruler
  • Pencil
  • Tape measure
  • Drill
  • Jigsaw, keyhole saw or scroll saw
  • Coarse sandpaper (60 to 80 grit)
  • Screwdriver
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Instructions

    • 1

      Establish the height of cat flap by measuring from the floor to the lowest point of the cat's belly while the cat is standing. The standard height for adult cats is about 5 inches.

    • 2

      Transfer the height to the door by measuring from the bottom of the door up. Mark the height with a pencil to indicate where the bottom of the cat flap will touch.

    • 3

      Find the center of the door and of the cat flap by measuring the width of each and dividing by 2. Mark with a pencil.

    • 4

      Line up the center of the door with that of the cat flap at the previously determined height. Mark corners with a pencil. Note: Some cat flaps come with a template. Substitute this for the cat flap, and trace the whole template instead of only marking the corners.

    • 5

      Use the square or ruler to draw straight lines between corner marks. Drill holes at each corner of the square or template outline.

    • 6

      Begin inside one of the drilled holes and cut along the lines with a jigsaw, keyhole saw or scroll saw. Smooth the rough edges of the hole with sandpaper.

    • 7

      Fit the inner frame -- the side with the lock and/or flap --- into the hole, inside the door.

    • 8

      Place screws into screw holes and tighten with the drill. Do not overtighten.

    • 9

      Fit the outer frame into the hole on the outside of the door, and screw into place as above.