Sandpits have always been a favourite with kids. But when the design also includes a gravel pit, a river of grass and raised walkways, you’ll have to drag them away from the fun.
When is a sandpit not just a sandpit? When it’s also an adventure playground. As well as the sand, this one has a quarry in the centre for large toy trucks, and there are raised walkways and upended logs that can be used as seats, a freeway for toy cars, or somewhere to have lunch. A shade sail provides shelter and it’s easily unclipped for cleaning. To keep the neighbourhood felines out, you can also cover the sand with a small piece of shadecloth held down by stones.
None of the dimensions are critical, so you can adapt them to suit your needs and space. Variations will also occur if you’re building on a slight slope as we did here. The cost of materials, excluding paint, is about $1000.
Gather your supplies
Corner poles (4) 100mm dia x 2400mm CCA treated pine
Stepping logs (4) 100mm dia x 2400mm CCA treated pine
Sandpit logs (11) 100mm dia x 2400mm CCA treated pine
A 200 x 100 x 2170mm
B 200 x 100 x 1875mm
C 200 x 100 x 2070mm
D 200 x 100 x 1980mm
E 200 x 100 x 910mm
F 200 x 100 x 1110mm
G 200 x 100 x 825mm
H 200 x 100 x 1110mm
I 200 x 100 x 1075mm
Walkway caps (not shown):
A 200 x 50 x 2280mm
B 200 x 50 x 1970mm
C 200 x 50 x 2300mm
D 200 x 50 x 2200mm
E 200 x 50 x 1120mm
F 200 x 50 x 1190mm
G 200 x 50 x 920mm
H 200 x 50 x 1280mm
I 200 x 50 x 1120mm
J 200 x 50 x 765mm divider (used on edge)
K 200 x 50 x 735mm divider (used on edge)
All ACQ treated pine. The stepping logs and sandpit logs are cut to shorter lengths, see steps 4 and 8. All dimensions are a guide only. Poles and stepping logs are CCA treated pine and need to be painted to be safe for kids.
- Step 1: Lay out and stretch the shade sail on the ground and mark the corners. Add an extra 150mm in each direction and mark in the pole positions. This little extra allows for the fittings. Mark the perimeter with set-out paint, here a 3.3m square. Then mark in the 1400mm-long stepping log diagonal at the front right and the back curve, using the dimensions on the diagram. Draw the curve freehand. For the ends of the internal curve of logs between the sandpit and gravel pit, measure roughly 1650mm from the front and 700mm from the left-hand side and 1600mm from the right-hand side and 700mm from the back. Mark in the curve. Also mark in the straight lines for the borders of the quarry rock area. None of the dimensions are critical, so you can adapt the shape to suit your needs.
- Step 2: Use a post-hole digger to make 600mm-deep holes for poles at each corner. The harder the ground, the stronger the post support, so persevere even if it’s tough.
- Step 3: Remove grass from the gravel pit area, and dig out a 250mm-deep hole where sandpit will be. Remove tree roots from excavations so you do not puncture weed mat once in place. Slightly increase depth around the edges of sandpit where logs are going to be installed, so they can be concreted in place. Also dig a diagonal trench at front right corner, to a depth of 200mm.
- Step 4: For stepping logs: From 100mm-diameter logs, cut 4 lengths each of 450, 500 and 550mm, and 2 of 600mm. To do this with a power saw, you’ll need to cut from both sides, as most saws won’t cut through the whole 100mm diameter in one hit.
- Step 5: Set out stepping logs on a bench, starting with a pair of 450mm logs, then adding two 500 and two 550mm, and the two 600mm logs. Then add pairs back down to the 450mm logs. Separate first pair so you have room to work. Align, then predrill a clearance hole through 1 and mark next with a long 7mm drill bit. Screw together with 125mm batten screws, then bring in next log (align bottoms with edge of bench to get right heights). Proceed with remaining logs, aligning and using a square so logs will be correctly aligned. If installing on a slope, stagger the bottoms of the logs slightly to make up the slope, so when installed the logs will still appear vertical.
- Step 6: Set the 14 logs into diagonal front trench. The assembly is quite heavy, so you’ll need 2 people to lift it into position. It will also tend to bend if carried flat, so it’s best to carry it vertically. Align in position, then use 3-4 bags of premixed concrete to set in place, making sure the log wall is plumb and centred to match the line of straight walls.
- Step 7: Set 4 corner posts in place, again using 2 people, one to hold each pole plumb and the other on concreting duties. These poles will give a head height under the shade cloth of about 1.8m – fine for little kids. For greater head height, use 2.7 or 3m poles. Prop with diagonal timbers if necessary. Let set.
- Step 8: For sandpit logs: cut thirty-three 750mm lengths of 100mm logs. Assembly of the 2 curved sandpit walls is easiest by screwing logs together in situ. It is done by eye and if the land slopes slightly there will be a slight fall in tops of logs. Screwing logs together is easiest with 2 people, one to hold each log in place and another to predrill and screw, again using 125mm batten screws. Once screwed together, align logs so they’re vertical and pour concrete around base. Haunch concrete around base on sand side of posts.
- Step 9: Cut the 200 x 100mm sleepers to their various lengths to form base of the walkways all around the perimeter and internal gravel pit. Each sleeper is a different length and they do not all have to be installed at once; you can add the caps and work in sections as you go. You’ll have to cut the 100mm-thick sleepers from the top and bottom surfaces, as most power saws will not cut them in one hit. While you’re in a cutting mood, use an angle grinder to cut the 1m lengths of 10mm steel rod in half so you have twenty-two 500mm lengths.
- Step 10: Use a long auger bit to bore centred 10mm holes through 200mm depths of sleepers in 2 places on short lengths and 3 on longer lengths. If your cordless drill can’t cope with the strain, you may need a power drill.
- Step 11: Level a bed for each sleeper, align and pin in place with 10mm rod. Use a heavy lump hammer to hammer in.
- Step 12: To build angled front gravel pit wall, mitre sleepers by setting power saw to cut at 22.5°. Cut from one side, turn over, align saw with cut, and cut from other side.
- Step 13: You can add caps as you go, or once all sleepers are set in place. To make them, cut 200 x 50mm pine to the lengths needed. Measure each one off the walkway sleepers as you go and cut mitres at ends where they meet. Most will be 45°, except at the angled quarry wall, which will be 22.5°. Where caps meet a round log or pole, scribe the ends to fit around by measuring and using a 100mm-dia offcut to pencil in the shape.
- Step 14: Cut out the circles with a jigsaw but take it easy, as cutting through 50mm of timber puts a strain on the saw. In some cases it will be easier to cut the corner mitre after the round is cut, so the exact length of cap can be marked when it is in position. Take off any remaining sharp corners so kids do not catch themselves on the timber.
- Step 15: Position caps on sleepers. Screw the caps to the sleepers, and also screw across mitres and into sides of logs to hold entire base structure together tightly. Use 175mm batten screws to screw 100mm sleepers together. Cut the 2 dividers (J and K) to suit the openings at ends of the sandpit area and screw to the sides of the sleepers just under the caps.
- Step 16: Use a plane or power sander to remove sharp corners and edge splinters. Also sand smooth the seating surfaces and seat edges.
- Step 17: To hang shade sail over area, bore 1 hole through top of each post, 50mm down from the top with diagonally opposite holes aligned. Use the long bit used for joining logs. Insert stainless steel eye bolts, add washers and tighten the nuts.
- Step 18: While only the logs and corner poles are made of CCA timber, it’s safest and more colourful to paint the whole play area. To coat logs, paint alternate singles or pairs of logs and let dry before painting the ones in between. This avoids paint bleeding into adjacent wet paint. The quickest way to paint the sleepers and seats of the walkways is to use a small roller. When rolling near the ground, use old cardboard at the base of the wall to avoid soiling the roller and painting the grass.
- Step 19: Pour 5-6 bags of 20mm gravel into sandpit and spread out. This provides drainage and levels the ground ready for the weed mat. Cut and nail weed mat to perimeter timber work, going about 200mm up sides, using galvanised clouts to hold it in place. Pour in about 0.5 cubic metres of washed builder’s sand – it’s clean and, when slightly damp, easy to mould into sandcastles. Turf the grass river, if needed.
- Step 20: Staple more weed mat to the ground in the gravel pit, using weed mat pins. Fold it at the sides to suit shape of the pit. Give the lucky stones a hose down, then put them in gravel pit.
- Step 21: Hook shade sail to posts using steel snap hooks; the cloth should be fairly taut. To keep cats out, cut a length of shadecloth to fit sandpit and hold down with stones.
You’ll also need
3 x 3m shade sail; set-out paint; post-hole digger; 125mm-long 7mm drill bit; 10mm-long auger bit; 75, 125 and 175mm batten screws; 16-18 bags premixed concrete; 10mm galvanised steel rod or reinforcement rod (eleven 1m lengths); 5-6 bags 20mm gravel; weed mat and pins; 0.5 cubic metres washed builder’s sand; 0.5 cubic metres lucky stones; 125mm stainless steel eye bolts (4); stainless steel snap hooks (4); exterior paint (see over page); turf (optional); 2m shadecloth (optional)