Learn to make the triple-combo fort, swing and climbing wall.
Cedar is the most weather-resistant, but any decking will do. Lay it out evenly all the way across the deck frame. The edges should be flush with the 2x8s on both sides.
To make sure the edges are really straight, attach a temporary piece of scrap to the side of the frame and line up all the decking against it before nailing in place.
Made from six 10’ 2x6 boards, there will be three A-frames in total. Two of the A-frames attach to the outside of the deck on both ends, and the third sits atop the deck in the middle. Cut the 2x6s with a 40-degree angle on top and a 70-degree angle on the bottom. Use a circular saw to make the cuts.
The ridgepole is the long 2x6 that will sit across all of the A-frames. To make sure it stays in place, cut a notch in the top of each A-frame. Cut a small piece of 2x6 scrap and trace the shape onto the top of the A-frame pieces.
Secure the tops of the A-frames together with a temporary piece of scrap wood to keep them flush while you raise them. Once they’re upright, screw the outside frames to the side of the deck, and the inside A-frame to the top of the deck with lag screws.
Set the ridgepole in place to make sure they’re all the right height, then use a framing square to make sure they’re at a 90-degree angle to the deck and secure them in place with temporary scrap wood to keep them from tilting.
On the enclosed half of the structure, one wall will be a climbing wall and the other will be covered translucent roofing. For the roofing side, connect the two A-frames with horizontal 2x4s every two feet. Repeat this step for the climbing wall, but use 2x6s instead. Make sure all the boards are level.
On the open half of the structure, reinforce the ridgepole where the swing will be. Screw a 2x4 to the bottom of the ridgepole to make an upside-down T. This will keep the ridgepole from bowing and widen the base for the swing hardware.
Screw a 2x6 horizontally near the top of the outside of the A-frame on the swing side of the structure. This is called a collar tie and will keep the A-frame sides from shifting under the torque of the swing. Add a vertical 2x4 on top of that to cradle to further support the ridgepole. This support will look like an upside-down T. Repeat on the inside of the opposite A-frame, but do not include the vertical 2x4.
Do not install a collar tie on the center A-frame, as people would hit their heads on it.
Attach shiplap siding all the way up the outer A-frame on the enclosed side of the structure. This is partly for looks, but the siding boards will also help to stabilize the frame. Let the siding extend past the A-frame beams.
Use hex-head screws with neoprene washers to attach the roofing to the 2x4 side beams. Overlap the roofing panels by one corrugation to prevent leaking. Leave a small overhang on the outside edge to cover up the edges where you cut the shiplap siding.
Pre-paint three sheets of 4’x8’ plywood. We used bright colors on the exterior and chalkboard paint on the interior side. Measure and cut the plywood to cover the side of the structure where the 2x6 supports are. You’ll only use about a quarter of the third sheet of plywood. Level and hammer all three in place, then trim the edges if necessary. Leave a small overhang on the outside to cover the edges where you cut the shiplap siding. Add an aluminum flashing ridge cap on top to keep the rain out.
Measure and cut a piece of plywood to sit across the interior against the back wall, resting on two of the roof supports. If your roof supports aren’t the same height, use scrap wood on the lower side to support the desk. Screw it in place at all four corners.
At this point, you're finished building. Check out the back view of the structure.