If you've visited a kindergarten recently, you may have seen children playing in an indoor water table: a sturdy work table with a low rim around the perimeter to hold a very shallow pool of water. And they love it, but at an indoor table they must exercise enough self-discipline to create quiet little water worlds and not a big wet mess; either that, or they need an adult there the whole time making sure things don't get out of hand.
An outdoor table allows for more rambunctious play, not to mention a less complicated design; indoor tables are typically built kid-waist high and require a rigid frame and legs. The water can also be a little deeper. Accordingly, the plans that follow are for an outdoor water table for kids. You'll save time, trouble and weight (filled with sand or gravel, rocks, and water, it will be heavy enough.)
Size and Depth
Build it on flat ground and block it to be perfectly level so the kids can play in it much as they play in the sandbox. The table should be long enough to present an independent play area at each end but be narrow enough that children ranged along opposing sides can reach in and play together. Again, observe a pair of kids playing dolls or cars on the rug and measure the distance from the belt of one to the other. I've found that a 2' x 4' table is fine for small kids, 2 1/2 x 6' good for older ones. Do not be tempted to make it so big the children are tempted to climb in, splash around, and bust it up.
If small kids have (even forbidden) access to a hose, they will eventually fill the water table to brimming. And despite being told not to, they will eventually go wading in it. A small child could conceivably slip, fall ...and a toddler can drown in even an inch of water. Unless you will have an adult in constant attendance, don't give them the chance to come to grief. If your youngest is under age 3, build a table with a low rim or drill drain holes all around so water can never get more than an inch deep. If the youngest is over age 6, water can be up to 4" deep. However, the table isn't meant to be a pool, but a miniworld with shallow, play oceans and rivers. I think that a box with 3" sides containing an inch or so of gravel and drain-hole drilled to give a maximum standing-water depth of 2" is best. The kids can have fun and you needn't worry. You can block up one end a couple of inches to give a shallow and deep end and enough slope to make little rivers through the gravel or sand when the hose is left on in a trickle. Kids can use wood blocks to dam the stream in 3"-deep pools to give a most satisfying, little waterfall. (We also provide a supply of little disposable bathroom-size paper cups for pouring. Otherwise, a succession of cooking measures, coffee mugs, and dangerous glass drinking vessels found their way out to the table.)
Build a 2 1/2'-Wide x 5'-Long x 4"-Deep Box
You will need:
- Electric circular saw with plywood-cutting blade.
- Electric drill/screw driver with Phillips-head drive bit and 1/16" drill bit.
- Long, measuring steel and pencil, or chalk and string snap line.
- Hammer and nail set.
- Caulking gun with 1 tube of outdoor-grade construction cement for wood, and 1 tube of (waterproof) adhesive, clear acrylic caulk.
- Sanding block or electric sander and sandpaper.
- Staple gun and 3/8" stainless steel staples (for sheet-good waterproofing).
- One 4' x 8' sheet of 1/2"-thick outdoor-glued plywood (smooth-one-side).
- Four 2' x 3' x 8' clear fir or spruce wall studs (straight in all dimensions).
- Fifty 1 1/2" long, #8 stainless-steel Phillips-head drywall screws.
- Twenty 1" long, #8 stainless-steel Phillips-head drywall screws.
- Twenty 3" galvanized finish nails.
- Twenty 1" galvanized finish nails.
- Paint or clear finish; 20' marine rubber bumper stock (or 4 or 5 old bicycle tires).
General assembly notes:
a. With 1/16 " drill bit, drill pilot holes through plywood to start all nail and screw holes.
b. Apply a bead of construction cement in all wood joints.
1. Cut ply into:
- One 5' 4" x 2' 6" wide bottom panel.
- Two 5' 4" x 6" wide side panels.
- Two 2', 6" x 6" wide end panels.
- Eight 6" triangles for corner gussets.
2. Cut framing from 2" x 3" studs, the sides first.
Lay the bottom panel on the ground and cut two lengths of 2" x 3" to be as long as it is. These will be the sides of the frame.
3. Fasten side-frame boards to the plywood bottom panel.
With smooth, finished face of the bottom ply facing up, set a 2" x 3" frame side board under each long edge, the 2" x 3"s "on edge"—with wider 3" surface facing out. Be sure outer edges of frame boards are even with edges of the bottom sheet. Fasten with screws 6" from end and placed every 6' ; screws will be through ply and down into the 2" x 3"s.
4. Cut frame ends and cross braces to fit bottom panel. Turn bottom panel over. Measure and cut 2" x 3"s to fit between ends of the frame boards just screwed on. Measure and cut 5 other lengths of 2 x 3 to form a ladder shape of cross braces between frame sides.
5. Tack fasten ends and braces. Arrange frame ends and cross braces in a ladder shape on underside of bottom panel. Cement and tack in place with long, easily removed nails through 2" x 3"s and into ply.
6. Reinforce underside of corners. Cut four triangular braces from scrap ply and place one at each corner. Use cement and short finish nails to fasten.
7. Carefully turn ply over again. Set screws through bottom panel and down to the frame members, screws about every 6". Now the bottom is framed.
8. Next, "box in" framed bottom with plywood side and end panels. Lay out the 5' 4" plywood side panels along the framed bottom, lower edge of side panels even with bottom edge of frame.
9. Lay out the plywood end panels. Arrange and (as needed) trim ends of sides and ends so all corners meet in a butt joint (end of one meets side edge of the other). Fasten sides and ends to frame with screws 6" apart, 1/2" up from lower edge. Remove tack nails from underside.
10. Cut and install corner cleats to strengthen up side of corners. Trim about a foot of scrap 2" x 3" to be a 1/2" square. Measuring in the box, cut four approx. 3" cleats—one to fit into each corner, upper end even with the rim. Drill staggered holes 3" in from corners and fasten cleats with glue and 1" screws through ply into cleats.
11. Caulk and water seal the box. Directions on waterproofing is explained below.
12. Install triangular top corner braces: Apply glue to bottom of remaining four plywood triangles and tack one at each corner of box, edges even with outside of box. Use small nails through triangle and into edges of plywood side and side panels and a long nail down into corner cleat. Countersink nails well into ply. Sand edges. Caulk all joints inside and out and water seal the plywood.
The table needn't be completely waterproof, but it makes for a better job, dryer kids, and less water waste if it is. Here are three options:
A good bead of sticky, clear acrylic caulk along insides of all seams will seal a well-fastened water table if wood surfaces to be caulked are dry and dust free. But, under repeated soakings, the caulk will work loose and plywood will deteriorate unless covered with a waterproof finish. Better is to caulk and then paint with clear outdoor varnish or several applications of sky blue, glossy, latex-enamel paint intended for house trim.
Better yet is the old way of sealing canoes and covering aircraft. Get ahold of enough lightweight canvas, blue denim, or any open weave, hard-finished fabric to cover the sides and bottom, plus a gallon or two of marine (canoe) paint or airplane dope. Sky blue is the best color. Cut fabric into panels to fit bottom and all sides with a good inch of overlap at seams and over the top of side and end panels. Along bound edges of the fabric, snip off enough 2" wide fabric tape to place over seams. Double-over cut edges and staple edges of fabric panels to the wood, snugging well and stapling into corners and pulling fabric over flat areas as tight as you can. Then apply successive coats of paint (under the second coat put painting tape over seams) till you have a smooth surface. Let the children help paint too; they love it, and modern latex enamels wash off little hands and out of clothes so long as you don't let them dry hard.
You can do a more modern job by replacing the fabric with more costly, but vastly stronger, fiberglass mat and replacing canoe paint with two-part epoxy resin—obtainable with directions at any boating-supply house. The resin comes in two parts; mixed together and with color added, it is applied over the fiberglass just as paint goes over cloth and will make a glossy minipool. (DO NOT let small kids help apply the resin, which is caustic and emits vinegary fumes till cured.)
Kids need something to make land out of. Sod looks good for a few minutes but quickly becomes sodden and gets the water muddy. Crushed rock is arguably the best, as its corners and many angular faces help it stay put better in water than sand or gravel. The heavier pebbles in gravel make more stable land areas under water than sand. Kids will bring in rocks, clumps of sod, grass and leaves, and who knows what all else, and the table can look a proper mess at the end of a day's play. It is easy to move gravel around under water with the hose to wash out peanut butter sandwich leavings, while fine sand grains will compact and hold trash.
Unless you want to enforce school-type discipline, the kids will splash and throw water. Crushed rock or gravel will stay put on the bottom while sand will splash out with the water, to get into silky young hair and small eyes.
Crushed rock and washed gravel are available from any aggregate-supply outlet. You won't want a dump truck full and you can buy it in bags, or you can get crushed marble and other decorative rock at most large nurseries. For a small table, you might find it easiest to buy fish-tank-bottom gravel from the pet store. The cheapest is natural stone, though the kids love to mix up a variety of virulent neon colors that hurt my eyes. Adding a new bag of a fresh color once in a while will enliven a slow afternoon.
Remember when you were a kid, how fascinating it was to play in a little stream? You could dam it up, float sticks down it, and imagine you were Tom Sawyer rafting the Mississippi. Block up one end of the water table an inch or two, with shorter supports every few inches downhill, hold the end of the garden hose in one corner with a brick, and leave the water on in a small flow. Let the overflow run over at the other end or drill drain holes to control water level. Experiment so water flow is strong enough to flow through but not so strong it erodes "land" areas. If it is the dry season, you can conserve water by running the overflow to your garden or permanent plantings.
You can attach elaborate faucets and drain cocks, but they just add weight. And you'll want to be able to move the table each day, lest the lawn under it become a swamp. A 1 1/2" hole in the bottom with a sink drain plug will ease emptying. A pair of 2" x 3"s with ends cut in an up angle and screwed to the bottom of the table, with a rope loop at one end, will make one-parent moving easier.