MOT Type 1 Limestone — The Complete Guide

MOT Type 1 is the UK's most widely used sub-base material for driveways, paths, roads, and hardstanding. If you're laying any kind of hard surface, MOT Type 1 is almost certainly what you need underneath it.

What is MOT Type 1 Limestone?

MOT Type 1 is a crushed limestone or granite aggregate that conforms to the Highways Agency's Specification for Highway Works — hence the "MOT" prefix. It consists of a graded mix of crushed stone particles ranging from 0mm to 40mm in size. The mix is carefully graded so that smaller particles fill the gaps between larger ones, creating a dense, stable, load-bearing layer when compacted. Unlike single-sized aggregates, MOT Type 1 compacts to form a solid base that won't shift or settle over time.

Common uses

Driveway sub-base beneath block paving, tarmac or resin
Road and car park construction
Patio and path sub-base
Hardstanding areas for vehicles and machinery
Commercial and industrial groundworks
Footings and trench backfill

Sizes & grades

Standard MOT Type 1 is graded 0–40mm. This means the material contains particles from dust up to 40mm stones. It should not be confused with Type 2, which has a different grading and is less suitable for heavily trafficked areas.

How much do you need?

For a standard driveway sub-base, you'll typically need a compacted depth of 100–150mm. To calculate tonnage: multiply the length (m) × width (m) × depth (m) × 2.1 (tonnes per m³). For example, a 5m × 3m driveway at 150mm depth needs 5 × 3 × 0.15 × 2.1 = 4.7 tonnes. Always add 10–15% for wastage and compaction.

Pro tip

Always compact MOT Type 1 in 100mm layers using a vibrating plate compactor. Compacting in one deep pass won't achieve the required density and can lead to settlement.