Build a DIY Dog Door Insert for Sliding Glass Doors

A DIY dog door for a sliding glass door can be assembled by framing a purchased pet flap with 2x2 lumber and attaching screen material to create a removable panel that slides into the existing door tracks.

Why Build a Custom Insert Instead of Buying One

Commercial sliding glass dog doors often cost several hundred dollars, while a homemade version using scrap wood and a basic flap unit keeps expenses lower. The approach allows exact sizing to the track height and width without permanent changes to the door frame. It also permits easy removal when the panel is not needed.

Materials and Tools Required

Obtain an extra-large dog door flap unit, replacement screen material or a screen repair kit, three 14-inch lengths of 2x2 lumber, and two 76.5-inch lengths of 2x2 lumber. Additional items include paint, a staple gun, staples, small nails or wood glue, and a drill with screws. These components create a stable frame that holds the flap and screen while fitting the track dimensions.

Measuring the Sliding Door Track

Measure the distance between the bottom screw holes on the flap unit to determine the width of the top and bottom frame pieces. Record the full height from the bottom track to the top inside track, then subtract half an inch from that measurement to allow the panel to seat properly. The resulting side pieces should measure 76.5 inches for a standard installation. Confirm that the 2x2 lumber will fit within the one-inch depth of the tracks on both top and side.

Cutting and Preparing the Frame Pieces

Cut the lumber to the recorded lengths. Apply paint to the wood before assembly to avoid later contact with the screen. Remove the solid insert from the purchased flap unit so the opening remains clear once the frame is complete.

Assembling the Frame Around the Flap

Position the bottom 14-inch piece against the flap and secure the flap sides with the supplied screws while holding the wood in place. Repeat the process for one long side piece, ensuring the bottom corners align. Add the top 14-inch piece and the second long side, then fasten the remaining screws. Place the final 14-inch piece across the very top of the assembly and attach it with one screw at each end to lock the corners.

Attaching the Screen Material

Cut screen to approximately 53 by 16 inches so it overlaps the opening. Lay the frame face down and staple the screen edges to the wood. Reinforce the staples by nailing thin scrap wood strips over the edges, keeping the strips inset from the outer perimeter so they do not interfere with track insertion.

Installing the Finished Panel

Slide the completed insert into the sliding door track by first pushing the top into the upper channel, then lowering the bottom into place. Shift the panel sideways into the side track where the sliding door normally closes. The sliding door itself can then be positioned to hold the insert securely from the opposite side. The panel remains removable for times when pet access is not desired.

Comparing DIY and Commercial Options

Ready-made patio panel pet doors from retailers provide spring-loaded adjustment and dual-pane options for better insulation, with prices starting around three hundred dollars. The DIY method trades some insulation performance for lower cost and full customization of height. Both approaches avoid cutting the glass or altering the door permanently.

Track height must allow enough clearance for installation; panels at the short end of an adjustment range can be difficult to seat over bottom track walls. Test fit before final assembly when possible.

Sources

• DIY Doggie Door Insert - SunnyMommy Creations
• Sliding Door Inserts - Dog Doors
• Sliding Glass Dog Doors