Step 1 Remove turf from selected area of your garden.
Step 2 Dig a narrow 70mmdeep trench around perimeter of area. Cut and place a length of treated pine garden edging into trench, 30mm above surrounding grass. Knock in pegs behind edging and screw them together.
Step 3 Using a power plane, slightly chamfer edges of sleepers to soften them.
Step 4 Determine dimensions of your sandpit. Cut 2 sleepers to go on 2 parallel sides and another 2 to fit between them on other sides. Place sleepers in position and butt them together in corners. Predrill using a long 4mm drill bit and screw together with bugle head screws.
Step 5 Fill sandpit with fine washed sand. Spread pine bark mulch in area between sandpit and garden edging.