How to Build Trap Doors in Treehouse Decks

Every kid needs a place to escape the adult world from time to time. Treehouses have supplied this escape for children for generations. When constructing a treehouse, the issue of a safe entrance can be a concern. A trapdoor, accessible from the bottom, puts the young home owner in the center of the platform for a safe entry. The framing underneath the trap is where the main strength lies.

Cut your trapdoor with a circular saw.
  1. Determine where you will be installing your trap door and what size it will be. For this tutorial, we will assume a 16-by-16 inch square. Measure between the nearest framing members and cut two treated 2-by-4s to fit snugly between them. Cut two more to length at 14 ½ inches.

  2. Mark out the square on top of the treehouse deck with a carpenter's square and drill a 1/8-inch hole in each corner, so that you can locate the square from the underside of the deck. Line your square up so that two sides are parallel to the closest framing members. Draw lines between the holes on the underside of the platform to form a 16-inch square. Draw a second square around this one, ¾ inches larger on each side.

  3. Line up the two 2-by-4s that were cut to fit between the framing members between the two nearest framing members on either side of the trapdoor so that the outside edges of the 2-by-4s are in line with the outside square you drew. This places them with their centers directly underneath the trapdoor square.

  4. Drive 3-inch treated deck screws through the outsides of the framing members into the ends of the 2-by-4s. Use at least three screws in each end of each board. Position the two 14 ½ inch 2-by-4s to line up with their outsides on the two remaining lines of the outside square, perpendicular to the 2-by-4s you just installed. Screw them in position as outlined above.

  5. Set a circular saw to the depth of your plywood deck material and cut along one edge of the trapdoor square on top of the deck. Attach two 3-inch utility hinges , evenly spaced along this line bridging the cut, with ¾ inch self tapping panhead sheet metal screws. The self-tapping point and aggressive thread make them ideal for this application.

  6. Cut the other three sides of the trap door with the saw. Bore a one-inch hole two inches from the edge opposite the hinges, eight inches from either side of the trap door so that it is centered. Use the hole to lift the trap door up.