How to Build a Tree House with One Tree

At one time or another, almost every child dreams of having a tree house. If you have only one tree on your property capable of supporting a house, your tree house will need to have a small footprint. However, this doesn't mean you can't make a tree house just right for spending long afternoons reading books or playing games with friends.

  • Measuring tape
  • 3 beams, 2 by 6 inches
  • 15 beams, 2 by 4 inches
  • 4 plywood sheets, 48 by 72 inches by 1/2 inch
  • 1 plywood sheet, 48 by 72 inches by 3/4 inch
  • Box of 3-inch wood screws
  • 9 lag screws
  • Power saw
  • Power drill
  • Ladder

Measure and Cut

Find an area in your tree where you can anchor your tree house to three points relatively level with one another. This might be on three limbs, the trunk and two points of a bent limb or any other arrangement that results in a triangle.

Measure all three sides of the triangle. Cut your 2-by-6 beams to match the length of each side of the triangle.

Cut three of your 2-by-4 beams to each match the length of each side of your triangle.

Cut the remaining 2-by-4 beams to 5 feet in length.

Floor and Ceiling

Arrange your 2-by-6 beams in a triangle corresponding to the triangle you planned in the tree. Lay them on the 2-inch sides, and screw them together with two screws at each end (for a total of four screws at each joint, two going in each direction).

Place the triangle on your sheet of 3/4-inch plywood, and outline it with a pencil. Cut out the floor along the outline.

Mount the triangle of plywood on your frame using one screw in each corner and an additional screw for every 2 feet of beam length.

Arrange three 2-by-4 beams (the same as you did with the 2-by-6 beams) in a triangle, and assemble them as you did the larger beams.

Place the triangle on a sheet of 1/2-inch plywood. Outline, cut and mount the plywood to this triangle just as you did with the thicker wood.

Wall Frames

Construct a rectangle using two of the 5-foot lengths of beam and two beams of the same length as one another (i.e. the matching pairs you cut to fit the length of your triangle sides).

Cut a piece of 1/2-inch plywood so that it is as wide as the custom length side of the square and 70 inches long.

Mount the plywood sheet on the rectangular frame. The 60-inch-long sides should be flush, and the sheet should overlap on one side by 6 inches and on the other by 4.

Screw the plywood sheet in place using one screw at each corner and one for every 2 feet of beam length.

Repeat steps one through four for the other two walls.

Cut a hole 2 feet wide by 4 feet high in one wall to serve as a door. If you want, you can cut out windows (usually 1 or 2 feet square) in the same or other faces.


Mount the floor in place using three lag screws per beam. Once mounted, test the floor and mounting using your adult body weight. If it's secure under your weight, it should be safe for your kids.

Hoist up the smallest wall frame, and set it in place with the 6-inch overlap pointing toward the ground. Use the overlap to mount it on the floor, using two screws at each corner and two more screws per 2 feet of beam length.

Hoist up and mount the other two sides just as you did with the smallest.

Hoist up the ceiling panel. It should nest in place within the top overlaps. Mount the walls to the ceiling panel with one screw at each corner.

Encourage your kids to decorate their tree house with paint, scrap carpet, handmade art or anything else they can think of.

Tips and Warnings

  • You will also need to see to a means of ascent up the tree. This could be a rope ladder, regular ladder, cargo web or even series of rock-climbing holds.

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