DIY Wooden Sandbox with a Lid (Plans, Materials, Cost)

This DIY sandbox plan sticks to the things that make a backyard sandbox last: walls tall enough to keep the sand in, a bottom that drains, a lid that actually gets used, and sand that's safe to dig in. The 4x4 ft size matches the standard size from Frame It All, a sandbox kit maker, and suits one or two small children. Scale it to 5x5 or 6x6 with the tables below.

Wooden sandbox dimensions and cut list

Outside size 48 x 48 in, inside about 45 x 45 in, walls 9.25 in tall (one 2x10). Frame It All recommends walls of at least 8-10 in and 6-8 in of sand, so the sand sits a couple of inches below the rim.

Buy one 2x10 x 16 ft (or two 8 ft), one 4x4 x 4 ft, four 1x6 x 8 ft and two 1x4 x 6 ft (or one 1x4 x 10 ft). Each half of the lid is four 1x6 boards on three cleats.

Materials and cost

These are rough ranges; cedar prices swing widely by region and season, so price your local yard before you commit. Pine is cheaper but rots sooner in contact with damp sand.

Tools: circular or miter saw, drill/driver, staple gun, tape measure, square, level, sandpaper or a sander, spade.

How to build the sandbox

1. Pick and level the spot Choose level ground with some afternoon shade, away from where you'll spray fertilizer. Strip the grass in a 4x4 ft square and rake it level; check with a level on a straight board.
2. Cut and sand Cut the walls, corner blocks, lid boards and cleats. Round over every edge and corner with sandpaper so there are no splinters at kid height.
3. Build the frame Stand a 45 in short wall between the two 48 in long walls at each end. Set a 4x4 corner block inside each corner and drive three 3 in exterior screws through each wall into the block. Pre-drill near board ends so cedar doesn't split.
4. Square it Measure both diagonals; they should match. Nudge the frame until they do, then set it in place and check level again.
5. Fit the liner Lay landscape fabric across the bottom and up the inside of the walls about 3 in, and staple it there. Fabric drains; plastic sheeting doesn't. On heavy clay that stays wet, put a few inches of gravel under the fabric.
6. Build the lid halves For each half, lay four 1x6 boards side by side, spaced so the half is 24 in wide (gaps of about ⅝ in, which let damp sand air out). Screw three cleats across them with 1¼ in screws, setting the cleats 2 in in from the ends so they drop just inside the walls and stop the lid sliding.
7. Hinge the lid Hinge each half to the top of one long wall with two strap hinges, so the halves open outward like book covers and rest on the grass. Check that they meet in the middle without binding.
8. Fill with sand Pour the bags in, rake level and dampen lightly. Leave the lid open until the sand surface is dry, then close it.

How many bags of play sand do you need?

Volume (cu ft) = length (ft) x width (ft) x depth (ft). Frame It All works on roughly 100 lb of sand per cubic foot, so each cubic foot is about two 50 lb bags. Our figures below use the outside dimensions, which rounds up a little; that's the amount you want on hand anyway.

Larger sizes are our arithmetic on Frame It All's 100 lb per cubic foot rule. That's a lot of weight to carry; ask your store about delivery for 30+ bags.

Is play sand safe? Choosing sand for kids

• Buy sand sold for sandboxes. The American Academy of Pediatrics (on HealthyChildren.org) recommends natural river or beach sand and warns against sand made from crushed limestone, crushed marble or crushed crystalline silica (quartz), and against anything obviously dusty.
• Washed and screened is better. Products such as Quikrete Premium Play Sand are described by the maker as washed and screened for children's sandboxes.
• Keep the dust down. The concern with sand is breathing fine dust (respirable crystalline silica), not touching it. Quikrete's safety data sheet notes that keeping play sand damp eliminates the dust hazard. Pour bags outdoors, slowly, and sprinkle the sand with water before play on dry days.
• No federal standard. The AAP notes the CPSC has no standards or labeling rules for play sand. If you're unsure about a sand, the AAP suggests a lab test; EPA regional or state asbestos coordinators can recommend a lab.

Sandbox safety and upkeep

• Cover it when not in use to keep animals out. Frame It All calls a cover the single most important sandbox accessory for exactly this reason.
• Let wet sand dry before closing the lid. The AAP notes wet, covered sand can harbor bacteria.
• Rake it regularly and check for debris; keep pets out.
• No railroad ties. The AAP warns that cheap railroad ties splinter and contain creosote. Use untreated rot-resistant lumber or a non-wood frame.
• Mind the lid. Hinged lids pinch fingers. Adults open and close it, and nobody plays on or under a half-open lid.
• Top up and replace. Add sand as it gets tracked out, and replace it if it's soiled, smells or has gone muddy.

Variations and buying instead

• Bigger box: for 6x6 ft or larger, add a center stake or cross-brace halfway along each wall so the sand doesn't bow the boards, and make the lid in three or four sections so each piece stays light.
• Sandbox with lid and roof: four corner posts with a canopy give shade; brace them well and keep the frame low.
• Raised sand table: build the box on legs for toddlers who prefer to stand; it needs less sand.
• Kits: cedar or composite sandbox kits with covers (Frame It All is one maker) cut out the sawing. Compare the kit's wall height and whether a cover is included before you buy.

Once the sandbox years are over, the same frame makes a ready-made raised bed: lift out the sand, fill with soil mix and plant. If you're planning more backyard builds, see our garden projects, the little free library build or, for the grown-ups' corner of the yard, our guide to building a greenhouse yourself and the foundations that keep it level.

Planning more backyard builds?

Many families who build a sandbox end up wanting a growing space next to it. If that's you, start with our backyard greenhouse kits guide for placement and sizing, compare the best greenhouse kits overall, or see the cheap greenhouse kits that are still worth buying if the sandbox ate the budget.