DIY materials lists: how to work out exactly what to buy (Australian sizes)
Short answer
Most DIY materials come down to three calculations: length (for timber and edging, rounded up to the lengths the shop sells), area (for pavers, tiles and membranes, plus an allowance for cuts), and volume (for soil, sand and road base, plus extra for compaction). Measure twice, plan around standard product sizes to cut waste, and convert volumes to tonnes when you're buying from a landscape supplier.
The most common DIY mistake isn’t a bad cut — it’s a second trip to the hardware store. These guides give you the full list for common jobs, in the sizes Australian stores actually sell.
The three calculations behind every list
1. Length — timber, edging, rails
Work out the total length you need, then plan it around the lengths the store sells (for example 1.8, 2.4, 3.0 and 3.6 m for sleepers). A bed designed around a 2.4 m sleeper wastes almost nothing; a 2.5 m bed wastes a lot.
2. Area — pavers, tiles, membranes, paint
Area = length × width (split odd shapes into rectangles). Then add an allowance for cuts and breakages: less for a simple straight-laid rectangle, more for diagonal patterns, curves and lots of edges. Check coverage rates on the product itself — adhesives, membranes and paints all state how many square metres a bag or tin covers.
3. Volume — soil, sand, road base, concrete
Volume (m³) = area (m²) × depth (m). Loose materials like road base shrink when compacted, so order extra. Landscape suppliers usually sell by the tonne, so multiply by the supplier’s density figure.
Guides in this series
- How many sleepers for a raised garden bed? — sleeper counts, fixings, soil volume and safe timber for vegetables.
- How much road base and sand for pavers? — depths, per-m² quantities and a 10 m² worked example.
Before you buy
- Check what needs a licence or approval first. Materials for a job you can’t legally do yourself are wasted money — see what you can legally DIY and council approval rules.
- Ask about delivery minimums for bulk materials — it’s often cheaper to order a little extra than pay a second delivery.
- Keep receipts and offcuts until the job’s finished.
Sources
Every rule on this page is taken from these official sources. If a rule has changed, please tell us and we’ll fix it.
This guide is general information, not legal or professional advice. Rules differ between states, councils and individual properties, and they change. Confirm with your state regulator or council before starting work, and if in doubt, get a licensed tradesperson.