How to Install a Doggie Door

Dog popping head out doggy door.
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What could be better than your dog letting itself in or out? That is the beauty of a weather-controlled doggie door that your dog can walk through when it wishes.

Store-bought doggie doors can be surprisingly expensive. Plus, with standard sizes, they might not be right for your dog's needs. Using simple materials and tools, you can create a safe, weather-resistant doggie door that eliminates the endless cycle of getting up to let the dog in and out. The soft rubber door flap is dog-friendly. Metal straps at the bottom of the flap meet a magnetic strip of tape on the frame, so the door will stay shut after the dog passes through.



  • Rubber doormat
  • (1) Two-by-four, 8 feet long, ripped to a width of 1 3/4 inches
  • (8) 2-inch screws
  • (3) 1/2-inch screws
  • (3) #6 gauge 3/4-inch bolts with matching lock washers and nuts
  • (2) #8 gauge 1/2-inch bolts with matching nuts
  • Trim, any style, minimum actual size 1 1/2 inches wide by 8 feet long
  • Exterior acrylic latex paint, any color
  • Magnetic tape, 1 inch wide by 30 inches long
  • Aluminum channel, 1/2-inch width by a minimum of 13 inches long
  • (2) #16 gauge metal straps, 1 1/2-inch wide by 12 inches long

Choose a Door Opening Size for Your Own Dog

Measure the width and height of your dog's torso to determine the door size that best suits your dog.

  • Small: An opening 5 1/2 inches wide by 8 inches high
  • Medium: An opening 8 inches wide by 12 inches high
  • Large: An opening 10 inches wide by 16 inches high

Cut Wood for the Frame

This rectangular wood frame will first act as a template for cutting an opening in the door and then will become a permanent frame for the door opening. Because exterior doors are 1 3/4 inches thick, you will need to rip (cut length-wise) a two-by-four to 1 3/4 inches. Most lumberyards can do this for you or you can use your own table or radial saw.

Next use your electric miter saw or hand saw to cut four pieces out of that lumber to create the frame.

  • Small: Cut two 8 1/2-inch pieces (width) and two 8-inch pieces (height)
  • Medium: Cut two 11-inch pieces (width) and two 12-inch pieces (height)
  • Large: Cut two 13-inch pieces (width) and two 16-inch pieces (height)

Build the Frame

You will build the doggie door frame separately from the house door, then you will insert the built frame in the house door. The four pieces will form a rectangle. The shorter (width) pieces will extend all the way across the width of the opening, with the longer (height) pieces sandwiched between the two width pieces.

Drill two pilot holes at the end of each piece. Add a few drops of wood glue at the very end of each of the two longer (height) pieces. Screw the width pieces into place and let cure for about two hours. After the glue has dried, paint it.

Make the Cut in the Door

The frame determines the size of the hole to cut in the door. Remove the house door from its hinges and place it horizontally on saw horses. Place the frame at the center of the door, 6 inches up and level with the bottom. Mark around the frame with your pencil. With the jigsaw or reciprocating saw, cut an opening in the door along the outline.

  • Small: 8 1/2 inches wide by 11 inches high
  • Medium: 11 inches wide by 15 inches high
  • Large: 13 inches wide by 19 inches high

Cut the Door Flap

Use the inner area of the completed frame as a template for determining the size of the door flap. Use either a light-colored Sharpie or painter's tape to mark the area since pencil will not show. Because the door flap needs to swing freely within the frame, step the measurements back by 1/16-inch on all sides. Remove the frame and cut with the utility knife.

Install Trim on the Frame

Install the trim on one side of the frame, similar to the way trim is installed around a window. Miter-cut the ends of the trim at 45 degrees. Extend the trim 1/2-inch beyond the frame, since this is necessary to hold the frame in the door. Nail in place with the cordless nailer or with a hammer and finish nails.

Attach Door Flap to the Frame

Cut a piece of the aluminum channel to the width of the door. Drill three holes in the channel, two about an inch from each end and one in the middle, then attach the channel to the top of the door opening.

Fit the rubber flap into the channel. Drill three 3/8-inch holes in the side of the channel, spacing them equally apart. Fit the bolts through the holes and secure the nuts and lock washers.

Attach the two 16-gauge metal straps to the very bottom of the flap, one strap on each side of the flap. The flap will be sandwiched between the straps. For small and medium doors, cut the straps to size with the hacksaw. Attach the straps to the flap with the two #8 gauge 1/2-inch bolts. Place these bolts at the very ends of the straps; if you place any bolt near the center, you risk scratching your dog's nose with the bolt.

Install the Frame

Fit the assembled frame into the hole in your door. Attach to the door by driving nails through the trim into the door. Cut matching trim for the other side and attach in a similar fashion. Apply a second coat of paint to all surfaces except for the flap and the aluminum channel. After the paint is completely dry, run two strips of magnetic tape to the bottom of the frame. Reattach the house door on its hinges with its pins.