ATLA News On-line
Newsletter Issue 7 No 4  November 1998

Compost Bins from Demolition Materials 

by Graham McKenzie


Tararua Wind Farm
Open Weekend

Build Your House with Water?

Embodied Energy Content
in NZ Materials

The GMO Controversy

Notice Board



Graham MacKenzie, an ATLA member from Wanganui, describes how to construct a compost bin from demolition materials, using the same plan that he has been using and improving upon for the last 40 years.


1. Bins must have roofs on at all times. A roof ensures aerobic bacteria action; no roof means anaerobic action, with loss of all nutrients. The roof of the bin is the same as the back size. Overlap roofing iron, or whatever you use, for rain cover. It is important to keep rain out or compost turns to sludge. Black plastic is optional to rainproof gap between top front and roof.

2. The bin must be situated with its back to the south-west.

3. The sides and back are constructed so that they can be turned upside down when the bottom of them starts to rot.

4. When making compost, pack the sides with your feet but never the centre.

5. The wooden tie is placed over the top planks to stop the bin from bulging.


1. Use urine, not water, if compost is dry.

2. No soil, apart from what clings to roots.

3. No lime: Use stinging nettle ie. calcium.

4. No ashes

5. No raw sawdust; only what has been well soaked in urine.


3D View


Side elevation

Front elevation


Sides (2)

2  -  4" x 6" x 1"

4  -  4" x 3" or 4" x 2"

4  -  6" x 6" x 20mm tanalised ply             (marine)

4  -  4" x 6" x 1" or similar

2  - uprights of whatever, nailed offset of centre so different lengths of side boards can be joined. Same with the back.


4  -  4" x 1" or a bit over.

1  -  upright, as above.

Space boards so there is a half inch cap or more, on sides and back.

Roof as above frame and iron.

Wooden tie

1  -  4'4" or 4'6" of 2" x 1"

2  -  5" x 2" x 1" blocks nailed on with        4' between them.

Bottom tie

4' x any width 1" thick or more, nailed 2" above the ground.


6   -   No.8 wire hooks

12 -   fence staples

2  -   roof hinge pins ie. 1/4", 5/16",            3/8" etc.

1  -   4'6" wide x 4'6" long black plastic fastened to the front of the bin on a 4'6" piece of 2" x 1". It sits in front of the spreader on the 6" square ply and should give the roof enough pitch to shed rain.

4  -  bricks or similar to sit bin on to keep it a little off the ground.

Removable front boards to retain compost; as many as required.