Platform Outdoor Sectional

Build the base frame from the side rails and cross members. Pocket holes (1-1/2" setting, 2-1/2" pocket-hole screws) work well, or you can countersink 2-1/2" self-tapping exterior screws instead. Use glue throughout and check for square as you go.

If you're using pocket holes, consider also drilling a set facing upward now for attaching the decking boards in the next step — it saves you working underneath later.

Attach the decking boards starting at the back and working inward, leaving a 1/2" gap between each board.

Attach the 2x2 cleats to the top of the decking using the 1-1/2" pocket-hole setting, 2-1/2" pocket-hole screws, and glue.

Attach the back board to both the 2x2 cleat and the 2x6 decking below it. Then split the remaining distance evenly and attach the center back boards.

We felt this back was plenty sturdy as built, but if you're concerned about the open end of the sectional, add a metal L bracket on the inside for extra security.