How to Strengthen Double Doors

Double doors allow for greater volumes of traffic and make a breeze of moving large objects, such as furniture and appliances.

Adding extra barrel bolts and upgrading the deadbolt adds strength to double doors.Adding extra barrel bolts and upgrading the deadbolt adds strength to double doors.
One drawback to double-door installations is a reduction in security. The joint between the two doors, both hinged on their outside edges, is significantly weaker than the joint between a typical single door and its jamb. There are several things that you can do to reinforce double doors to increase their security and help them last longer.

Remove the screws from the interior face plate of your deadbolt lock with a screwdriver. Remove the lock tumbler by pulling out on both sides. Remove the screws in the face plate around the bolt on the edge of the door and pull the bolt from the door.

Replace the 1 to 1/4-inch standard bolt with a long throw deadbolt, available at your local hardware store. Insert the new bolt, replace the screws in the plate on the edge of the door, insert the two halves of the tumbler through the hole in the bolt and thread the mounting screws. Tighten them with a screwdriver.

Remove the bolt receiver plate on the opposite door, across from the deadbolt. Use a 1-inch paddle bit to deepen the bolt receiver hole to 2 1/4 inches. Add a brass reinforcement receiver bracket over the edge of the door to reinforce the 2 inches on either side of the bolt and cover the gap to prevent prying the bolt. Attach it to the door's edge with screws provided with the bracket.

Set a barrel bolt latch 3 inches from the knob edge at the bottom of the passage door. The stationary door probably already has a small one. Choose a 1/4-inch bolt at least a 3/4-inches long. Mark the screw holes from the bolt bracket onto the face of the door and drill a 1/4-inch deep pilot hole in each spot with a 1/8-inch bit. Drive the screws in with a screwdriver to attach the bolt to the door face.

Mark the end of the bolt on the floor where it hits to position the receiving hole. Drill a 3/4-inch deep hole with a 5/16-inch bit. Drop the bolt into the hole and turn it to the latched position. Test the deadbolt to make sure the placement is accurate, file the edge of the hole with a round rasp if needed to allow the deadbolt to open and close smoothly.

Add a second barrel bolt at the top of the passage door in the same way, add a top barrel bolt to the stationary door if it doesn't already have one, using the same procedure.

Replace the screws on the jamb side of the hinges on both doors with 3-inch treated deck screws to anchor the hinges to the frame behind the jamb. Run the screws in flush, and do not over-tighten.

Things You Will Need

  • Screwdriver
  • Barrel bolt latches
  • Long throw deadbolt
  • Corded drill
  • 1-inch paddle bit
  • 5/16-inch bit
  • Brass reinforcement plate
  • 3-inch treated deck screws

About the Author

Mark Morris started writing professionally in 1995. He has published a novel and stage plays with SEEDS studio. Morris specializes in many topics and has 15 years of professional carpentry experience. He is a voice, acting and film teacher. He also teaches stage craft and lectures on playwriting for Oklahoma Christian University.