Crushed Concrete Calculator UK

Table of contents

• What is the Crushed Concrete Calculator UK?
• How sub-base dimensions, compacted layer depths, aggregate material grades, and delivery formats calculate tonnage requirements
• Example Calculation: Estimating compacted volume, total tonnage, 850kg bulk bags, and tipper delivery costs for a 50m² sub-base
• Major UK Crushed Concrete & Aggregates Cost Drivers: Type 1 Recycled vs Primary MOT Type 1, 6F2 capped stone sizing, soil compaction factors, and grab truck access
• Smart Aggregate Procurement & Groundwork Strategies: Calculating compaction ratios, optimizing tipper vs bulk bag loads, and specifying geotextile separation membranes
• The Essential UK Crushed Concrete Sub-Base Audit Checklist
• How to use the Crushed Concrete Calculator UK
• Frequently Asked Questions (FAQs)

Use this Crushed Concrete Calculator UK to estimate total compacted sub-base volumes in cubic metres (m³), required crushed aggregate tonnage, equivalent 850kg jumbo bulk bag quantities, and estimated supply delivery charges for civil engineering, driveway, patio, and building foundation projects across the United Kingdom. Designed for UK groundworkers, civil engineers, driveway installers, builders, and DIY renovators, this tool evaluates material requirements based on sub-base ground length and width in metres, compacted layer depth in millimetres (mm), aggregate grade specification (Type 1 Recycled 40mm to dust, 6F2 / 6F5 Hardcore 75mm to dust, or Clean Crushed 40mm without dust), and supply delivery format (Loose Grab / Tipper Load or Jumbo Bulk Bags).

What is the Crushed Concrete Calculator UK?

The Crushed Concrete Calculator UK is a precision civil engineering sub-base material estimator and aggregate budgeting tool engineered for UK groundworks, driveway construction, and structural foundation projects.

By entering your sub-base ground length and width in metres, specifying your required compacted layer depth in millimetres, selecting your target crushed concrete grade, and choosing between loose tipper haulage or jumbo bulk bag delivery, this tool calculates exact compacted volumes, tonnage including a 10% compaction and wastage buffer, aggregate bag counts, and material supply fees under current UK highways specification standards (MCHW Volume 1 Specification for Highway Works).

How sub-base dimensions, compacted layer depths, aggregate material grades, and delivery formats calculate tonnage requirements

The calculator evaluates complete crushed aggregate material volumes, compacted weight conversion rates, and delivery costs by combining sub-base ground dimensions with aggregate grade density factors, compaction settlement buffers, and supply haulage formats:

To deliver accurate tonnage figures and material cost estimates aligned with current UK quarry prices, recycled aggregate suppliers, and highways construction standards, the tool applies the following mathematical algorithms:

• Compacted Sub-Base Volume Formula:
  • Compacted Volume (m³) = Length (m) x Width (m) x [Compacted Depth (mm) / 1000].
• Aggregate Density Factors & Material Grades:
  • Type 1 Recycled Crushed Concrete (40mm down to dust / 1.90 tonnes/m³): High-density crushed concrete and hardbound aggregate screened from 40mm down to dust, interlocking under heavy roller compaction to form a solid sub-base for driveways and highways.
  • 6F2 / 6F5 Crushed Hardcore (75mm down to dust / 1.85 tonnes/m³): Coarse crushed concrete capping layer containing stone up to 75mm, ideal for stabilizing soft subgrades and deep fill trench foundations.
  • Clean Crushed Concrete (40mm open-graded / 1.65 tonnes/m³): Crushed aggregate washed free of dust fines, forming a permeable, free-draining stone layer for land drainage trenches and SuDS-compliant sub-bases.
• Compaction Settlement & Wastage Buffer (+10% Allowance):
  • Operating a heavy vibrating roller or wacker plate compresses loose aggregate fines into air voids, reducing volume by roughly 8% to 12%. The tool multiplies raw tonnage by 1.10 to ensure sufficient bulk supply.
  • Gross Tonnage (Tonnes) = Compacted Volume (m³) x Grade Density (t/m³) x 1.10.
• Supply Delivery Formats & Cost Calculations:
  • Loose Tipper / Grab Lorry Delivery (£32.00 / tonne average): Bulk aggregate delivered loose by 8-wheel tipper (up to 20t) or grab truck (up to 16t) for large-scale driveway or site groundworks.
  • Jumbo Bulk Bags (£45.00 / bag average): Standard 850kg (0.85 tonne) crane-offloaded jumbo bulk bags designed for sites with tight access or residential driveway storage.

Example Calculation: Estimating compacted volume, total tonnage, 850kg bulk bags, and tipper delivery costs for a 50m² sub-base

To observe how sub-base ground dimensions, compacted layer depths, material grade densities, and delivery formats interact during a UK driveway preparation project, consider this 50m² sub-base scenario.

Example: A contractor prepares a 10.0m long by 5.0m wide driveway sub-base (50.0m² area) to a compacted depth of 150mm using Type 1 Recycled Crushed Concrete delivered loose via tipper truck.

• Input Project Specifications:
  • Sub-base Dimensions: 10.0m Length x 5.0m Width (50.0 m² Ground Area)
  • Compacted Layer Depth: 150mm (0.15m Depth)
  • Aggregate Grade: Type 1 Recycled Crushed Concrete (1.90 t/m³ Density)
  • Supply & Delivery Format: Loose Grab / Tipper Load (£32.00 / tonne)
• Step-by-Step Material Breakdown:
  • Compacted Volume (50.0 m² x 0.15m): 7.50 m³
  • Net Dry Tonnage (7.50 m³ x 1.90 t/m³): 14.25 Tonnes
  • Gross Tonnage including 10% Compaction/Waste (14.25t x 1.10): 15.68 Tonnes
  • Equivalent 850kg Bulk Bags (15.68t / 0.85t): 19 Jumbo Bags
  • Loose Tipper Material Cost (15.68 Tonnes x £32.00): £501.76
• Project Summary & Unit Rates:
  • Average Sub-base Material Cost: £10.04 / m²
  • Recommended Compaction Equipment: Vibrating twin-drum roller or 100kg wacker plate

The calculation demonstrates that laying a 50m² sub-base at 150mm compacted depth requires 15.68 tonnes of loose recycled Type 1 crushed concrete (or 19 jumbo bulk bags), costing £501.76 delivered via tipper truck.

Major UK Crushed Concrete & Aggregates Cost Drivers: Type 1 Recycled vs Primary MOT Type 1, 6F2 capped stone sizing, soil compaction factors, and grab truck access

Understanding aggregate grading standards, compaction ratios, and site delivery logistics ensures a stable sub-base while keeping material procurement costs efficient:

• Type 1 Recycled Crushed Concrete vs Primary Quarried MOT Type 1:
  • Recycled crushed concrete (produced from crushed demolition rubble and concrete structures) costs 30% to 40% less than primary quarried limestone or granite, offering an eco-friendly, cost-effective sub-base for driveways and patios.
  • Primary MOT Type 1 quarry aggregate provides perfectly uniform stone grading and frost-resistant properties, which may be specified for heavy commercial highways or high-load industrial hardstandings.
• 6F2 / 6F5 Capped Stone Sizing and Subgrade Stabilization:
  • Coarse 6F2 crushed hardcore (containing larger stone pieces up to 75mm) is ideal for filling deep subgrade trenches, capping soft clay sub-soils, or stabilizing muddy access tracks before applying a final 50mm Type 1 blinding layer.
  • Using 6F2 for deep fills reduces overall material expenditure compared to filling thick excavations entirely with finer, higher-cost Type 1 aggregates.
• Compaction Settlement Factors and Layer Lift Limits:
  • Loose crushed aggregate loses 8% to 12% of its volume when compacted as dust particles interlock into air voids under heavy vibration.
  • Compaction must be executed in maximum 150mm lifts (layers); attempting to compact layers thicker than 150mm in a single pass leaves uncompacted air pockets near the bottom, causing future surface subsidence.
• Site Delivery Haulage Logistics (Tipper vs Grab Lorry Access):
  • Delivering loose aggregates via 8-wheel tipper trucks (up to 20-tonne capacity) offers the lowest per-tonne material rate, provided the site has clear road access and tipping space.
  • Where access is restricted by narrow driveways, walls, or fences, hiring an 8-wheel grab lorry (up to 16-tonne capacity) allows the driver to crane-reach and deposit aggregate over obstacles directly onto the work area for a modest haulage premium.

Smart Aggregate Procurement & Groundwork Strategies: Calculating compaction ratios, optimizing tipper vs bulk bag loads, and specifying geotextile separation membranes

Applying structured material calculation rules and smart site preparation practices enables project managers and self-builders to optimize aggregate orders and prevent ground contamination:

• Always Lay Heavy Non-Woven Geotextile Separation Membrane:
  • Line the excavated soil subgrade with a heavy-duty non-woven geotextile membrane before spreading crushed concrete. The membrane prevents subgrade clay from churning up into the stone layer, preserving sub-base structural integrity.
• Bulk Order Loose Tipper Loads for Quantities Exceeding 10 Tonnes:
  • For projects requiring over 10 tonnes of aggregate, opt for loose tipper delivery instead of jumbo bulk bags to save up to £15 to £20 per tonne on material supply fees.
• Factor a 10% Compaction and Waste Buffer into Orders:
  • Multiply calculated dry cubic volume by 1.10 to ensure sufficient bulk tonnage is delivered, avoiding costly shortfalls and secondary delivery fees mid-compaction.

The Essential UK Crushed Concrete Sub-Base Audit Checklist

Following a systematic sub-base audit checklist guarantees proper excavation depth, secure geotextile separation, and maximum compaction density:

✅ Subgrade Excavation & Membrane Audit

• Verify Subgrade Formation Depth & Bearing Strength: Confirm soil dig-out reaches firm subsoil level, removing soft topsoil, organic matter, and tree roots across the entire formation bed.
• Inspect Geotextile Membrane Overlaps: Ensure non-woven geotextile fabric covers the entire excavated bed with a minimum 300mm overlap along all sheet joints.

✅ Aggregate Spreading & Compaction Audit

• Enforce 150mm Maximum Lift Layers: Confirm loose crushed concrete is spread and levelled in shallow layers no greater than 150mm before applying mechanical compaction.
• Audit Mechanical Roller / Wacker Pass Rates: Inspect compaction using a minimum 100kg vibrating plate or twin-drum roller, completing 4 to 6 passes per layer until no visible surface movement remains.

✅ Final Grading & Blinding Checklist

• Check Surface Cross-Falls & Levels: Verify the compacted sub-base surface maintains required 1:40 (2.5%) drainage falls and correct depth margins below finished paving or asphalt levels.
• Apply Sharp Sand / Grano Dust Blinding Course: Confirm a thin 15mm to 25mm blinding layer of sharp sand or grano dust is spread over coarse aggregate to seal surface voids prior to laying block paving or concrete slab foundations.

How to use the Crushed Concrete Calculator UK

1. Sub-base Ground Dimensions (Metres): Enter the total length and width of your sub-base area in metres (for example, a standard double driveway sub-base typically measures roughly 10.0m long by 5.0m wide).
2. Compacting Layer Depth (Millimetres – mm): Input your target compacted aggregate depth in millimetres—enter 100mm for garden patios and timber shed bases, 150mm to 200mm for residential vehicle driveways, or 250mm+ for heavy commercial roadways and parking areas.
3. Crushed Concrete Specification: Select your aggregate material grade—choose “Type 1 Recycled (40mm-dust)” for standard interlocking sub-base layers, “6F2 / 6F5 Hardcore (75mm-dust)” for coarse subgrade capping and deep trench filling, or “Clean Crushed (40mm No Dust)” for free-draining permeable stone beds.
4. Supply & Delivery Format: Choose your haulage option—select “Loose Grab / Tipper Load (£32/t)” for bulk site deliveries via tipper or grab lorry, or “Jumbo Bulk Bags (£45/bag)” for 850kg crane-offloaded bulk bags on sites with restricted access.
5. Review Crushed Concrete Material Estimate: Examine the results breakdown panel to view your total compacted volume in cubic metres, total tonnage including the 10% compaction buffer, equivalent 850kg bulk bag counts, and estimated material supply cost.

Frequently Asked Questions (FAQs)

How many tonnes of crushed concrete do I need per cubic metre in the UK?
One cubic metre ($1.0\text{ m}^3$) of compacted Type 1 recycled crushed concrete weighs approximately 1.9 tonnes. When factoring in the standard 10% compaction settlement and ground loss buffer during mechanical rolling, you should calculate roughly 2.1 tonnes per cubic metre of excavated sub-base volume.

What is the difference between Type 1 recycled crushed concrete and 6F2 hardcore?
Type 1 recycled crushed concrete is screened to a finer 40mm down to dust particle size, allowing it to interlock tightly under compaction to form a smooth sub-base directly beneath paving, concrete, or asphalt. 6F2 hardcore is a coarser 75mm down to dust aggregate designed for deep fill ground stabilization and subgrade capping.

How deep should a driveway sub-base of crushed concrete be?
For residential vehicle driveways supporting standard cars and vans, a compacted Type 1 crushed concrete sub-base layer should be between 150mm and 200mm deep, laid over a non-woven geotextile separation membrane and mechanically compacted in 150mm maximum lifts.

How much weight is in a jumbo bulk bag of crushed concrete?
Standard UK aggregate jumbo bulk bags typically contain 850kg (0.85 tonnes) of crushed concrete or aggregate. One 850kg bulk bag covers approximately 3.0 square metres at a compacted depth of 100mm, or 2.0 square metres at a depth of 150mm.

Sources

• Highways England – Specification for Highway Works (MCHW) Volume 1 Series 800 Road Pavements and Unbound Materials
• WRAP (Waste & Resources Action Programme) – Quality Protocol for the production of recycled aggregates from inert waste
• MPA (Mineral Products Association) – Technical guidance on recycled aggregate densities, compaction ratios, and grading standards

This calculator provides estimated compacted sub-base volumes, aggregate tonnage, jumbo bulk bag quantities, and material delivery costs for UK groundworks projects based on standard industry density benchmarks. Calculations serve as an estimation guide and should be verified through an on-site ground survey and aggregate supplier quote prior to placing bulk material orders.