How To Timber - Compost Bin





  1. This compost bin measures 98cm x 98cm x 90cm and has a cubic capacity of approximately 780L, the same construction method will work for a larger or smaller bin, however you may need additional support posts for a larger model.
  2. Cut 15cm x 2.5cm (6" x 1") timber into 18 lengths of 98cm (38.5").
  3. Lay 2 posts flat on the ground at a distance apart equal to the length of the boards (98cm). Starting from the top of the posts attach a board (using 2 screws per post) making sure it's flush with the edges and tops of the posts, attach the first board then ensuring the boards are tight up against each other work down the posts attaching 6 boards in total.
  4. Repeat this process with the other 2 posts and another 6 boards.
  5. You've now made 2 sides of the compost bin. Stand up one of the sides of the bin and ask a helper to hold it steady while you attach another board to the top (one screw for now), hold up the second completed side and attach the same board to the top of that, once you are happy that the board is in the correct position and not twisted (check by measuring the gap between the two sides at the top and the bottom - it should be even) you can screw the remaining 2 screws into the top board and fix the remaining 5 boards below the board you have just placed.
  6. You should now have a bin with 3 completed sides. Carefully position the bin, the open side will be the front, check that the bin is square (the diagonals should be an equal length and the open side should measure the same distance between posts as the rear side).
  7. Mark the position of the posts on the ground, remove the bin and dig 4 holes approximately 30cm deep, reposition the bin with the legs into the holes, the side boards should now be resting on the ground and the bin should be square and level (vertically and horizontally).
  8. Fix the posts into the ground with either concrete or a quick setting post mix (we recommend this).
  9. Measure the gap between the posts and cut 6 more boards to fit (make the boards approximately 3mm narrower than the gap to allow for expansion).
  10. Once the posts are set in the ground nail two batons to the front posts (open side) flush with the outside edge of the post and facing each other. Now hold one of the cut boards on the inside of the bin against the battens you've just fixed to the posts and mark a line for the position of the next two battens, remove the board and attach the battens set back slightly from the line you've just marked to ensure sufficient space for the boards to slide.
  11. You should now have gaps between the battens on each of the posts into which you can slide the remaining boards to form a removable front panel.



Notes

 

Additional bins can be attached to the first with shared central sides, therefore additional bins only require 2 fixed and one removable side.

If you prefer using a closed compost bin system, make two of the posts (must be on the same side as each other) 5cm higher than the sides of the bin, attach a batten across these and stretch a plastic sheet across the top. Alternatively you could make a lid using battens and gravel boards and place this over the top, the higher posts will allow water to runoff by creating a slope.

If the bin is to be relocated in the not too distant future, you can fix the posts by packing the gaps in the hole with stones, broken bricks etc, this won't be as strong, but it will be removable.



Tools

 

  • Drill driver
  • Spade
  • Bucket
  • Hammer
  • Spirit level
  • Saw



Materials

 

  • 4 of 1.2m (4') posts 10cm (4") square.
  • Enough 15cm (6") pressure treated timber boards to cut into 18 lengths of 98cm and 6 lengths of approximately 78cm (i.e. 8 x 3m boards).
  • Post fixing material a quick drying product such as postfix is slightly more expensive than concrete, but very fast setting and much easier to use.
  • Enough batten (pressure treated timber approx 2.5cm x 1cm (1" x .5") to make 4 x 90cm strips the timber you use for this must not be so wide that two strips plus the gap for the gravel boards is greater than the width of your post, if you can't source timber of a suitable width attach one set of battens overlapping the front of the posts so that they stick out slightly.
  • Screws 5cm (2") approx 72
  • Nails 5cm (2") approx 16