How much Type 1 do I need? Tonnage by area and depth
Type 1 is ordered by the tonne but designed by depth, which is where most over- and under-ordering happens. The arithmetic is simple once you know the bulk density and remember that loose material shrinks when it is compacted.
The calculation
Compacted MOT Type 1 has a bulk density of roughly 2.0–2.1 tonnes per cubic metre. So: area in m² × depth in metres × 2.1 = tonnes needed.
Worked example: a 60 m² driveway at 150 mm compacted depth is 60 × 0.15 × 2.1 = around 19 tonnes — one full 8-wheel tipper load.
Quick rule of thumb: one tonne covers about 5 m² at 100 mm compacted depth, or about 10 m² at 50 mm.
Our aggregate calculator does this for you across Type 1, capping and bedding materials if you would rather not do the sums.
Allow for compaction and for the dig being uneven
Loose material occupies roughly 15–20% more volume than the same material compacted. If you calculate on loose volume you will end up short.
Excavations are never as neat as the drawing. Add 5–10% on top of the calculated figure for over-dig, soft spots and losses.
Rounding up to a full load is often the sensible call — part loads carry the same vehicle movement as full ones.
Depths that are actually specified
Patios and foot-traffic paths: 100 mm compacted.
Domestic driveways, cars and light vans: 150 mm compacted.
Heavier vehicular use, yards, or soft clay subsoil: 200–300 mm, often over a capping layer of 6F2 or 6F5.
Compact in layers of no more than 200–250 mm — one deep lift will not compact through, whatever plant you use.
Ordering it
Give tonnage, the delivery postcode, when you need it and how a lorry gets in. Say if there is anything overhead — a tipper needs about 7 m of clearance to raise its body.
If arisings are going out, ask for a two-way load: the lorry removes your muck to a licensed facility and returns loaded with Type 1.
Atlas Stone Supplies delivers Type 1 nationwide by tipper, grab or bulk bag. Request a quote with your tonnage and postcode.
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