Your Guide to Building a Cedar Sandbox for Your Kids

What You Need to Build a Cedar Sandbox

• 2 – 2” x 4” x 8’ cedar boards
• 9 – 5/4” x 6” x 8’ cedar deck boards
• Penetrating waterproofing sealant
• 108 – 2” exterior deck screws
• 24 – 50-lb bags of sand
• Miter saw, Circular saw or handsaw
• Tape measure
• Drill with drill bits and screwdriver
• Framing square
• Pencil
• Rafter square
• Paintbrush
• Medium-grit sandpaper
• Flat shovel and post-hole digger
• 8 – 2×4 x 12” (side supports)
• 8 – 5/4×6 x 5’ (side walls)
• 4 – 2×4 x 24” (corner supports)
• 4 – 5/4×6 x 22” (seats)
• 4 – 5/4×6 x 11” (seats)

Getting Started

1. Cut your lumber to the appropriate size You may get this done at the store that you purchase the board from. Simply make the cuts you will need to install the seats.


2. Seal the lumber Use a penetrating waterproofing sealant to paint the lumber. Allow it a few hours to dry completely.


3. Set up the box components Take four of the deck boards and set them up into a square on a flat surface. See that the boards overlap each other on all four corners so that all four sides of the box have the same dimensions. Square the corners up with a framing square and use two deck screws to secure each of the corners. To prevent splitting, drill pilot holes. Create two identical boxes by repeating the steps with the second four boards.


4. Begin to assemble your sandbox Turn one of the boxes over and place it over the other one. Make sure the corner joints are in alternate directions. Measure the boxes diagonally from one corner to the other and adjust it so that you get the same length for both the diagonals.


5. Install the corner supports Next, you will need to install a corner post to the inside of each corner of the cedar sandbox. Check the underside of the sandbox to ensure that the top of the sandbox and the support post is in the same level or slightly below. Use two deck screws per board to secure the support posts and ensure that they fit snugly. Carry out the same process on the other corners.


6. Add your side supports Use the deck screws to attach two side supports on each inner side of the sandbox from the outside. The side supports should be perpendicular to the sandbox. Be sure that they are slightly below the bottom edge or at the same level of the top of the sandbox. Attach the side supports to the cedar sandbox using four decking screws, two in each deck board.


7. Mark the spots for the seats With the sandbox still upside down, slide two deck board scraps under a corner. The edge should be aligned with the tip of the corner. The rafter square should ensure that both boards maintain a 45° angle to the sides of the cedar sandbox. Mark the outer edges of the sandbox, and number the corner and the underside of the boards so that you know which corner goes with which seat. Carry out the same process with the other corners.


8. Cut your seats and seal them Use the marked lines to cut the seat and sandpaper the edges to take away any splinters. Use the waterproof sealant to paint the seats and leave them to dry.


9. Prep the location Now place the cedar sandbox in the location you wish to set it up in. Use a flat shovel to make the surface leveled and take away any tree roots or sod.


10. Get your cedar sandbox going Turn the sandbox over to the right side and set it in place. Add a marking on the ground for the corner posts and keep the sandbox aside. Dig the holes for the corner support using a post-hole digger or a shovel. Skip this step if you aren’t planning on currying the corner supports. Place the corners of the sandbox into the holes and adjust it until it is at the same level of the ground in all directions. Place the landscape fabric under the sandbox and tuck it in lightly to weight the sides down. Backfill the support holes after pushing the fabric away from the corners. Make sure the soil is tightened well.


11. Add your seats Drill pilot holes in your sandbox corners and install the seats using deck screws until all corners are done. Touch up the seats and screw heads using waterproofing sealant.


12. Add the sand to your new cedar sandbox You’re all done! Now all you have to do is add the sand, a few toys, and watch your kids have a whale of a time!