How to build a sandbox under your deck

We recently moved back into the city from the suburbs. We lucked into finding a house with a great deck in the back, a place for a garden and a double car garage (very rare downtown) but it's lacking a yard (in the back, we do have a front yard). Since there are a bunch of parks close by and the beach is just down the street it doesn't bother us much. But there are those times when you would like to send the kids outside play so my husband came up with this great idea to build a sandbox under our deck.

Here's the sandbox with the lid on. The lid is made of 2 pieces with one having rope handles to pull it out.
Here it is with the 1st piece out and stacked at the end of the deck.
And with the 2nd piece out - there is a sandbox. I was afraid the lid pieces were going to be very heavy but they - just a little awkward thanks to their length. But the being apple to cover the sandbox completely means that we don't lose any deck space for BBQs. Plus, it helps to keep the sand a little more dry, and stops the raccoons from using it as a litter box (euwh!).

Since it was my husband's project, he didn't think to take step-by-step photos of the process like I would have. But, here how it was made:

1. We located the stringers - the supports that run under the deck, perpendicular to the decking and decided where we would create the opening. Like studs in a wall, stringers are typically 16" apart - so remove 2 would give us a nice 4' opening.

2. Using a reciprocating saw, we cut the deck boards at both ends of what would be the opening, so the deck boards that remained were flush with the last stringer.

3. Next we removed the deck boards in between the two cuts - first by attempting to unscrew them, and when that didn't work, by prying/pulling/smashing them. We had hoped to reuse them, but unfortunately they didn't come off the deck structure very well without being destroyed (thanks to stripped screws). In fact, had they come off cleanly, we would have been able to do the entire project with just 2 new lengths of 2x6 and a couple of 1x6's - the rest would have all been reused.

4. With thee decking removed and the supports exposed, we removed two of the 2x6 stringers. The reciprocating saw again came in handy to cut the screws where the stringers were attached to the supports at either - meaning the wood could be reused, and the supports stayed in place.

5. Our deck is supported by two 2x12's that are spaced 48" apart, and run the length of the deck underneath the stringers. We cut 1x6's to fit in between 2x12's, and stacked them on top of each other at each end to close the opening under neath the remaining stringers - this created a perfect 4'x4' box to fill with sand!

In this picture, the wood to the left of the pink bucket is the top of the 2x12 support, and to the right of the pink bucket is the top 1x6 (the other is buried below the sand)

6. On the outside of the 2x12's, we built small benches - which also support the lid. The benches are supported by short lengths of 2x6 that are screwed into the 2x12 with metal hangers, and are attached to the outside supports of the deck with metal hangers.

7. For the lids, we simply built boxes using 2x6's the fit snuggly inside the outside deck supports and the remaining deck stringers, leaving a 2" gap in the middle, and a 2" gap on either end. Because the decking is 5/4" thick, we had to trim 5/4" off the bottom of each 2x6, so when the decking was put on top it would be level with the rest of the deck.

8. To make sure the deck boards on top the lids were cut to the right length, we placed the box-frames in gap, side by side, and then measured the length of each 1x6 deck board to go on top - using one length of wood for the entire gap. We attach each deck board to the box-frame first, before moving on to the next. Finally, once all of the deck boards were cut and attached, we removed the whole lid (at this point still one large piece). After chalking a line down the middle of the deck boards (in 2" gap that we left between the box-frames), and used a circular saw to cut the whole thing into two perfectly fitting pieces.

9. Finally, to make it easier to remove the first lid we attached two rope handles. The ropes are fed through a hole drilled in the 2x6 support on the underside of the lid, and then knotted. The second lid piece doesn't need rope handles, since it is easily moved once the first lid is removed.

Here is the sandbox when we want to use the deck for entertaining. It's a great that we can still have a sandbox in our small space.

The chairs fold up so they can be put to the side (they are a curbside find that I have to paint at some point to spruce them up) and the bbq can move over to the side.

I love that my hubby was so innovative to come up with such a great idea - now the kids aren't digging in my garden. The kids are happy to have a sandbox again, now I just have to figure out how to keep the sand out of the house.