Sandbox Bench Build - Relaxing Garage Woodworking

If you have a toddler, you know two things:

They love sand.
Neighborhood cats loves sand (for... other reasons).

You need a cover. A tarp is ugly and collects rain water. A heavy plywood lid is a back-breaker to move. The solution? A lid that folds open to become comfortable bench seats.

It is magic. Closed, it's a flat deck. Open, it's a play arena with seating for Mom and Dad.

Material Selection: Safety First

Cedar or Redwood: Do not use "Pressure Treated" lumber for a sandbox. The chemicals (copper azole, etc.) are safe for deck joists but maybe not for a toddler eating the sand. Cedar is naturally rot-resistant and smells nice.
Stainless Steel Screws: Standard deck screws will rust/streak eventually. Stainless costs 2x more but lasts forever.
Landscaping Fabric: To line the bottom.

The Build Process

Step 1: The Box

I built a simple 4x4 foot square box using 2x10 cedar boards.

Joinery: I used simple butt joints reinforced with lag screws.
The Bottom: I stapled heavy-duty weed barrier fabric to the bottom. This lets rain water drain out into the earth, but stops weeds from growing up into the sand. Never put a solid wood bottom on an outdoor sandbox—it will turn into a swamp.

Step 2: The Bench Mechanism (The Brain Teaser)

The lid consists of two sides. Each side has 3 sections connected by hinges.

Section A: Fixed to the box.
Section B: The "Backrest".
Section C: The "Seat".

When you lift the handle:

Section C folds back onto Section B.
Sections B+C fold up to form the backrest.
Gravity holds it in place.

Hinge Placement: This is critical.

Between A & B: Hinges on TOP.
Between B & C: Hinges on BOTTOM. If you get this wrong, it won't fold. Test with scrap wood first!

Step 3: Sanding and Softening

Kids fall. A lot. I took my router with a 1/4" round-over bit and softened every single edge. No sharp corners. I sanded everything to 120 grit to prevent splinters in little knees.

Step 4: Finishing

I chose TotalBoat Halcyon Varnish. It's a marine-grade clear coat. It seals the wood but is water-based and safe once cured. It keeps the cedar looking red and fresh instead of turning grey.

Filling It Up

I bought 15 bags of "Play Sand" from the hardware store. Tip: Don't use "Paver Sand" or "Construction Sand." They are gritty and dusty. Play sand is washed and screened.

Conclusion

This project took one Saturday to build and cost about $150. My son spends hours in it. And the best part? I can sit on the bench with my coffee and watch him play without having to sit in the sand myself.

It keeps the cats out, the debris out, and the fun in. A must-build for parents.