1. Choose a firm, level, well-drained site and mark out the area, approximately 1950mm square. Dig a 30mm deep channel for the bottom log of each wall.
2. To make the four walls, lay out logs in pairs, with the end of the top log overhanging the bottom log at one end by 150mm (Fig. 6). Measure and mark in 300mm on the top log at the overhanging end (approximately 150mm on the set back bottom log), and 150mm from the other end of each top log. Drill a 10 mm vertical hole through both logs at these points. Due to the combined thickness of the two logs, the width of the bottom log may need to be reduced around the bottom of the holes with a hammer and chisel to allow the bolt to fit. Fix together with 300 x 10mm bolts with the washers and nuts on the underside of the wall.
3. Fit the assembled log walls in position as shown (Fig. 6). Drill 10mm holes through the top logs of each wall at the corners and the bottom logs of the connecting walls. Bolt together as before.
4. Line the bottom of the pit with Weed Mat from your Mitre 10 store. This material effectively restricts weed growth while providing good drainage.
5. Now you can add the sand. You may also wish to add a corner seat as indicated, using 150 x 25mm treated pine cut to size and fixed with 75mm galvanised bullet head nails.