How much MOT Type 1 do I need for a driveway?

For a standard UK driveway carrying cars, a sub-base depth of 150mm is recommended. For a 50m² area at this depth, you would need approximately 17–18 tonnes of MOT Type 1, which accounts for compaction.

What is the difference between MOT Type 1 and Type 3?

MOT Type 1 contains 'fines' (dust) which helps it compact into a solid, impermeable mass. MOT Type 3 is 'open-graded' (it has fewer fines), allowing water to drain through it. Type 3 is mandatory for permeable SuDS-compliant driveways.

What does 'MOT' stand for?

MOT stands for the Ministry of Transport. Materials labeled 'MOT' meet the specific engineering standards required for use in public highway construction in the UK.

How much does a bulk bag of aggregate weigh?

In the UK, a standard 'Jumbo' bulk bag typically contains between 800kg and 850kg of material. Most professional calculations assume 0.85 tonnes per bag.

How much MOT Type 1 do I need for a driveway?

For a standard UK driveway carrying cars, a sub-base depth of 150mm is recommended. For a 50m² area at this depth, you would need approximately 17–18 tonnes of MOT Type 1, which accounts for compaction.

What is the difference between MOT Type 1 and Type 3?

MOT Type 1 contains 'fines' (dust) which helps it compact into a solid, impermeable mass. MOT Type 3 is 'open-graded' (it has fewer fines), allowing water to drain through it. Type 3 is mandatory for permeable SuDS-compliant driveways.

What does 'MOT' stand for?

MOT stands for the Ministry of Transport. Materials labeled 'MOT' meet the specific engineering standards required for use in public highway construction in the UK.

How much does a bulk bag of aggregate weigh?

In the UK, a standard 'Jumbo' bulk bag typically contains between 800kg and 850kg of material. Most professional calculations assume 0.85 tonnes per bag.

Sub-Base Calculator

Calculate tonnage for MOT Type 1, Type 3, and Scalpings.

Project Area (m²)

Target Compacted Depth (mm)

Driveway: 150mm | Patio: 100mm

Sub-Base Material

Tonnage Report

MOT Type 1: This is the industry standard for sub-bases. It is a 'graded' material ranging from 40mm down to dust, which interlocks perfectly when compacted.

Foundation Logic: The Importance of Sub-Base

Structural Integrity

A driveway or patio is only as good as the ground beneath it. Skipping or undersizing the sub-base is the #1 cause of sinking paving and cracked concrete in the UK.

Our **aggregate calculator** uses industry-standard densities for crushed stone, helping you order exactly what you need to ensure a stable foundation.

Depth Guidelines

Domestic Patio100mm Depth

Domestic Driveway150mm Depth

Commercial / Heavy200mm+ Depth

The Compaction Factor

When you spread 'loose' aggregate, it contains a lot of air. Using a vibrating plate compactor (wacker plate) or a twin-drum roller forces the air out and interlocks the stones.

**Crucial:** This process reduces the volume. You will typically need **20% more material** in its loose state to achieve your final target compacted depth. Our calculator includes a 10% allowance, but for heavy compaction, always round up your order.

SuDS Compliance

If you are building a new driveway over 5m² without a soakaway, you must use **MOT Type 3** and permeable paving to comply with UK flood prevention laws.

Geotextile Membrane

Always lay a heavy-duty geotextile membrane (weed suppressant) before the MOT. This prevents the sub-base from sinking into the soft sub-soil (mud) over time.

Pro Tip: 8-Wheel Grabs

If you need more than 10 tonnes, stop buying bulk bags. Ordering a 'loose' load from a local quarry via an 8-wheel grab or tipper lorry can save you up to 50% on the material cost.

Sub-Base & Aggregates FAQ

Technical Disclaimer

Aggregate densities vary by quarry and moisture content. This tool provides an engineering estimate. Always verify weights with your supplier before ordering large quantities.