Instantly estimate volume (m³) and weight (kg / tonnes) of aggregate for driveways, sub-bases, concrete, drainage & landscaping projects.
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Aggregate Volume & Weight Formula Explained
Our guide uses standard civil engineering formulas to convert your area dimensions into volume and weight. Here is the exact method used.
Formula Used by This Aggregate Guide
Volume (m³) = Length (m) × Width (m) × (Depth mm ÷ 1000)
Weight (kg) = Volume (m³) × Bulk Density (kg/m³)
Tonnes = Weight (kg) ÷ 1000
Where:
L= Length of the area in meters
W= Width of the area in meters
D= Depth of aggregate layer in millimeters (divided by 1000 to convert to meters)
Density= Bulk density of the selected aggregate type (kg/m³)
Worked Example:A 6m × 3m garden path, 75mm deep, using pea gravel (1,580 kg/m³):
Volume = 6 × 3 × (75 ÷ 1000) =1.35 m³
Weight = 1.35 × 1,580 =2,133 kg
Tonnes = 2,133 ÷ 1000 =2.13 tonnes
+10% buffer =2.34 tonnes recommended to order
For irregular shapes, divide the area into rectangles, estimate each one separately, then add the volumes together. For more on sub-base concrete slab design, see our Concrete Slab Guide .
Why Use Our Free Aggregate Guide?
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18 Aggregate Types
Covers gravel, sand, limestone, granite, recycled aggregate, MOT Type 1, ballast, pea gravel, and more with 2026 density values.
Metric & Imperial
Switch between meters/millimeters and feet/inches at a click. Useful for working with both UK and international project specifications.
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Worked Examples – Aggregate Estimate for Common Projects
Real-world examples showing how to estimate aggregate for driveways, paths, and sub-bases.
Example 1: Residential Driveway Sub-Base (Crushed Stone)
Length of Driveway 12 m
Width of Driveway 3.5 m
Aggregate Depth (Loose) 150 mm
Aggregate Type Type 1 MOT Crushed Stone (1,750 kg/m³)
Volume 12 × 3.5 × 0.15 = 6.3 m³
Estimated Weight 6.3 × 1,750 = 11,025 kg (11.025 t)
10% Buffer 1,102.5 kg extra
12.13 tonnes
Example 2: Decorative Garden Path (Pea Gravel)
Path Length 8 m
Path Width 1.2 m
Gravel Depth 60 mm
Aggregate Type 10mm Pea Gravel (1,580 kg/m³)
Volume 8 × 1.2 × 0.06 = 0.576 m³
Estimated Weight 0.576 × 1,580 = 910 kg (0.91 t)
10% Buffer 91 kg extra
1.0 tonne
Example 3: Concrete Slab Sub-Base (Hardcore/Recycled Aggregate)
Slab Length 6 m
Slab Width 4 m
Sub-Base Depth 100 mm
Aggregate Type Recycled Crushed Concrete (1,350 kg/m³)
Volume 6 × 4 × 0.10 = 2.4 m³
Estimated Weight 2.4 × 1,350 = 3,240 kg (3.24 t)
15% Buffer (uneven ground) 486 kg extra
3.73 tonnes
Types of Aggregate Used in Construction & Landscaping (2026)
Understanding which aggregate to use is as important as estimating how much you need. Each material has different properties, strengths, and applications.
Crushed Stone / Crushed Gravel
Produced by mechanically crushing large rocks such as limestone, granite, or basalt. Angular particles interlock under compaction, providing excellent load-bearing capacity. Widely used as a sub-base for roads, driveways, buildings, and industrial floors.
Natural Gravel
Naturally rounded stones sourced from riverbeds or glacial deposits. Smooth, rounded shape makes it easier to spread but less stable under load than crushed stone. Used in concrete mixes, drainage layers, garden paths, and decorative surfaces.
Sand (Sharp & Soft)
Fine granular material essential in concrete, mortar, rendering, and plastering. Sharp sand (coarser, angular) is used in concrete; soft sand (finer, rounder) in mortar, pointing, and rendering. Also used as blinding and pipe bedding.
Pea Gravel (6–10mm)
Small, smooth, rounded pebbles 6–10mm in size. Ideal for drainage layers, French drains, soakaways, pipe bedding, and decorative garden paths. Water passes freely through the voids due to its uniform size and rounded shape.
Type 1 MOT Hardcore
A well-graded crushed rock aggregate (0–40mm) conforming to the UK Highways Agency’s Series 600 specification. The industry standard for sub-base construction under driveways, patios, roads, and any paved surface that must support vehicle loads.
Granite Aggregate
One of the hardest and most durable aggregates available. Used in high-specification concrete mixes, road surfacing, and heavy-duty industrial sub-bases. Higher density than limestone or gravel, with excellent resistance to polishing and wear.
Shingle & Decorative Pebbles
Larger rounded stones in various colours and sizes used for garden landscaping, driveways, ornamental borders, and low-maintenance ground cover. Available in natural tones and coloured varieties. Provides excellent drainage and weed suppression.
Recycled Aggregate (2026)
Crushed concrete, brick, and demolition waste reprocessed for reuse as sub-base material. In 2026, recycled aggregate is increasingly specified on UK and international projects to meet sustainability targets and reduce waste sent to landfill. Cost-effective and widely available.
Ballast (All-in Aggregate)
A pre-mixed blend of coarse gravel and sharp sand used to make concrete on-site. Contains both fine and coarse particles in the correct proportions for a standard concrete mix when combined with cement and water. Convenient for small pours.
Crushed Limestone
A widely available, lower-cost alternative to granite aggregate. Excellent for sub-base construction, road base, and agricultural use. Slightly lower hardness than granite but still highly suitable for most construction applications. Popular in Pakistan and the UK.
Basalt Aggregate
Dense volcanic rock aggregate with very high PSV (Polished Stone Value), making it ideal for road surfacing where skid resistance is critical. Also used in high-strength concrete mixes and railway ballast where durability and load resistance are paramount.
Crushed Asphalt / Planings
Recycled asphalt planings from road resurfacing. Used as a sub-base or driveway surfacing material. When rolled and compacted, asphalt planings bind together to form a semi-hard surface. Very cost-effective; widely available across the UK and Pakistan.
Aggregate Size Guide – Which Grade Do You Need?
Aggregate is sold in different grades defined by particle size. Choosing the correct grade is essential for performance. This updated 2026 size guide covers all common UK and international specifications.
- Size / Grade: Fine Sand; Particle Size: 0 – 2 mm; Typical Application: Mortar, rendering, plaster, bedding; Recommended Depth: 25 – 50 mm; Key Property: Smooth finish, fine joints
- Size / Grade: Sharp Sand; Particle Size: 0 – 4 mm; Typical Application: Concrete, paving, screed; Recommended Depth: 25 – 50 mm; Key Property: Angular, high bond strength
- Size / Grade: Pea Gravel; Particle Size: 6 – 10 mm; Typical Application: Drainage, pipe bedding, paths; Recommended Depth: 75 – 100 mm; Key Property: Free-draining, smooth
- Size / Grade: 10mm Gravel; Particle Size: 10 mm; Typical Application: Concrete mix, footpaths, blinding; Recommended Depth: 75 – 100 mm; Key Property: Compact concrete mix
- Size / Grade: 14mm Gravel; Particle Size: 14 mm; Typical Application: Concrete, decorative driveways; Recommended Depth: 80 – 120 mm; Key Property: General purpose
- Size / Grade: 20mm Gravel; Particle Size: 20 mm; Typical Application: Concrete mix, driveways, sub-base; Recommended Depth: 100 – 150 mm; Key Property: Most common concrete aggregate
- Size / Grade: 40mm Crushed Stone; Particle Size: 40 mm; Typical Application: Road base, heavy sub-base, fill; Recommended Depth: 150 – 250 mm; Key Property: High load capacity
- Size / Grade: Type 1 MOT (0–40mm); Particle Size: 0 – 40 mm; Typical Application: Driveway & road sub-base, UK standard; Recommended Depth: 150 – 300 mm; Key Property: Locks together under compaction
- Size / Grade: Type 2 MOT (0–75mm); Particle Size: 0 – 75 mm; Typical Application: Bulk fill, general sub-base; Recommended Depth: 200 – 400 mm; Key Property: Lower grade than Type 1
- Size / Grade: Shingle / Decorative; Particle Size: 10 – 20 mm; Typical Application: Landscaping, garden paths, borders; Recommended Depth: 50 – 75 mm; Key Property: Decorative, low maintenance
- Size / Grade: Ballast (All-in); Particle Size: 0 – 20 mm; Typical Application: On-site concrete mixing; Recommended Depth: N/A — mixed into concrete; Key Property: Combined fine & coarse aggregate
- Size / Grade: Railway Ballast; Particle Size: 28 – 50 mm; Typical Application: Railway track bed, heavy drainage; Recommended Depth: 250 – 350 mm; Key Property: Very high load resistance
Aggregate Bulk Density Reference Table 2026
Bulk density varies by aggregate type, moisture content, and compaction. These standard 2026 reference values are used to convert between volume and weight. Always confirm exact figures with your supplier for large orders.
- Aggregate Type: Loose Dry Sand; Bulk Density (kg/m³): 1,400 – 1,500; Tonnes per m³: 1.40 – 1.50; State: Loose, uncompacted; Typical Use: Mortar, rendering
- Aggregate Type: Compacted / Wet Sand; Bulk Density (kg/m³): 1,600 – 1,750; Tonnes per m³: 1.60 – 1.75; State: Compacted; Typical Use: Bedding layers, screeds
- Aggregate Type: Pea Gravel (10mm); Bulk Density (kg/m³): 1,520 – 1,600; Tonnes per m³: 1.52 – 1.60; State: Loose; Typical Use: Drainage, pipe bedding
- Aggregate Type: Natural Gravel (20mm); Bulk Density (kg/m³): 1,520 – 1,680; Tonnes per m³: 1.52 – 1.68; State: Loose to medium; Typical Use: Concrete, driveways
- Aggregate Type: Crushed Stone / Gravel; Bulk Density (kg/m³): 1,600 – 1,750; Tonnes per m³: 1.60 – 1.75; State: Loose; Typical Use: Sub-base, roads
- Aggregate Type: Type 1 MOT Hardcore; Bulk Density (kg/m³): 1,700 – 1,800; Tonnes per m³: 1.70 – 1.80; State: Loose (compacts higher); Typical Use: Driveway sub-base
- Aggregate Type: Crushed Limestone; Bulk Density (kg/m³): 1,700 – 1,800; Tonnes per m³: 1.70 – 1.80; State: Loose; Typical Use: Sub-base, concrete
- Aggregate Type: Granite Aggregate; Bulk Density (kg/m³): 1,750 – 1,900; Tonnes per m³: 1.75 – 1.90; State: Loose; Typical Use: High-spec concrete, roads
- Aggregate Type: Basalt Aggregate; Bulk Density (kg/m³): 1,650 – 1,800; Tonnes per m³: 1.65 – 1.80; State: Loose; Typical Use: Road surfacing, concrete
- Aggregate Type: Recycled Crushed Concrete; Bulk Density (kg/m³): 1,200 – 1,500; Tonnes per m³: 1.20 – 1.50; State: Loose; Typical Use: Sub-base, fill, 2026 builds
- Aggregate Type: Recycled Brick / Hardcore; Bulk Density (kg/m³): 1,200 – 1,350; Tonnes per m³: 1.20 – 1.35; State: Loose; Typical Use: Bulk fill, general infill
- Aggregate Type: Ballast (All-in Aggregate); Bulk Density (kg/m³): 1,400 – 1,500; Tonnes per m³: 1.40 – 1.50; State: Loose; Typical Use: On-site concrete mixing
- Aggregate Type: Crushed Asphalt Planings; Bulk Density (kg/m³): 1,500 – 1,650; Tonnes per m³: 1.50 – 1.65; State: Loose; Typical Use: Driveway topping, sub-base
Aggregate Coverage Guide – How Much Per Square Metre?
Quick reference for how many tonnes of aggregate you need per m² at standard depths. Based on 1,600 kg/m³ bulk density (adjust for other materials).
- Depth: 25 mm; Volume per m²: 0.025 m³; Kg per m² (1,600 kg/m³): 40 kg/m²; Tonnes per m²: 0.04 t/m²; Typical Application: Blinding layer, top dressing
- Depth: 50 mm; Volume per m²: 0.05 m³; Kg per m² (1,600 kg/m³): 80 kg/m²; Tonnes per m²: 0.08 t/m²; Typical Application: Decorative path, garden border
- Depth: 75 mm; Volume per m²: 0.075 m³; Kg per m² (1,600 kg/m³): 120 kg/m²; Tonnes per m²: 0.12 t/m²; Typical Application: Footpath, patio sub-base
- Depth: 100 mm; Volume per m²: 0.1 m³; Kg per m² (1,600 kg/m³): 160 kg/m²; Tonnes per m²: 0.16 t/m²; Typical Application: Standard driveway sub-base
- Depth: 150 mm; Volume per m²: 0.15 m³; Kg per m² (1,600 kg/m³): 240 kg/m²; Tonnes per m²: 0.24 t/m²; Typical Application: Heavy driveway, slab sub-base
- Depth: 200 mm; Volume per m²: 0.2 m³; Kg per m² (1,600 kg/m³): 320 kg/m²; Tonnes per m²: 0.32 t/m²; Typical Application: Road sub-base, commercial
- Depth: 300 mm; Volume per m²: 0.3 m³; Kg per m² (1,600 kg/m³): 480 kg/m²; Tonnes per m²: 0.48 t/m²; Typical Application: Heavy road base, deep sub-base
Handy Rule: How Much is One Tonne of Gravel?
At 100mm depth, 1 tonne of gravel (at 1,600 kg/m³) covers approximately6.25 m². At 50mm depth, 1 tonne covers approximately12.5 m². Use these quick references for approximate ordering before using the full guide above.
How Aggregate Is Used in Construction & Civil Engineering
Aggregate is the backbone of nearly every construction project. Understanding how it is used helps you specify the right material, depth, and grade for each application.
Sub-Base Preparation for Roads & Driveways
A correctly designed sub-base is the most critical factor in the longevity of any paved surface. A well-graded, compacted layer of crushed stone or Type 1 MOT distributes vehicle loads from the surface into the ground below. Without it, paving, concrete, and asphalt will crack, sink, and fail prematurely. TheUK Highways Authorityspecifies Type 1 MOT at 150–300mm compacted depth for public road construction.
Aggregate in Concrete Production & Mixes
Aggregate makes up 60–75% of total concrete volume by weight. Coarse aggregate (10–20mm gravel or crushed stone) provides structural bulk and compressive strength, while fine aggregate (sand) fills the voids between particles and improves workability and surface finish. The aggregate-to-cement ratio is critical to achieving the target concrete strength grade. For guidance on concrete mix design, refer toBS EN 12620:2013 – Aggregate for Concrete. Use ourConcrete Guidefor mix volumes.
Drainage Layers, French Drains & Soakaways
Single-size clean aggregate (10mm or 20mm gravel with no fines) is the standard material for drainage trenches, soakaways, French drains, and behind retaining walls. The uniform gaps between particles allow water to flow freely while supporting surrounding soil and structures. Always use clean, washed aggregate for drainage — any fine material (silt or clay) will rapidly block the voids and reduce drainage capacity to zero. For soakaway design guidance, seeUK Planning Portal guidance on drainage.
Gravel Driveway & Road Surfacing
Gravel and crushed stone are used as a finished surface for rural roads, farm tracks, and residential driveways. A depth of 75–150mm of compacted aggregate provides a durable, free-draining surface at low cost. Angular crushed stone is preferred over rounded gravel as its irregular shape interlocks when compacted, reducing surface migration. In 2026, self-binding gravel (a mix containing natural binders) has become increasingly popular for a stable, dust-free driveway surface that meets UK SuDS drainage requirements.
Garden Landscaping, Paths & Ground Cover
Decorative aggregates — pea gravel, shingle, slate chippings, and coloured stone — are widely used in garden paths, planting borders, rockeries, and ground cover. They suppress weeds, reduce water evaporation from soil, and provide an attractive low-maintenance finish. A typical garden application uses 50–75mm depth laid over a permeablegeotextile weed membrane (RHS guidance)for best results.
Pipe Bedding, Surround & Trench Backfill
Fine aggregate — pea gravel or sharp sand — is used to bed and surround underground pipes, protecting them from point loading, sharp objects in the backfill, and differential settlement. The bedding zone typically extends 150mm below and 150mm above the pipe crown. Specifications are set byCIRIA pipeline installation guidanceand BS EN 1610 for sewer construction.
Sustainable Recycled Aggregate Use in 2026
In 2026, recycled aggregate accounts for approximately 28% of aggregate consumption in the UK, according toMineral Products Association data. Recycled crushed concrete and brick from demolition is processed to meet BS 8500 and BS EN 206 specifications for use as sub-base fill in non-structural applications. Using recycled aggregate reduces the carbon footprint of construction, cuts material costs by 20–40%, and helps projects meet BREEAM and Net Zero Carbon targets increasingly required in 2026 planning conditions.
Blinding Layer Under Concrete Slabs
A blinding layer of fine sharp sand or fine gravel (25–50mm deep) is laid on top of the compacted sub-base before placing concrete. It provides a smooth, level platform for the damp-proof membrane (DPM) and reinforcement mesh, prevents puncturing of the DPM, and fills any surface irregularities in the sub-base. Without blinding, stones can pierce the DPM and compromise moisture protection of the slab above. See ourSlab Guidefor full slab and sub-base quantities.
Pro Tips for Aggregate Projects – 2026 Best Practice
Expert advice from construction professionals to get the best results from your aggregate project.
Always Order 10% Extra
Aggregate loses 10–15% of its loose depth during compaction. A 100mm loose layer becomes approximately 85mm compacted. Always add at least 10% to your estimated quantity before ordering to ensure you have enough after compaction and spillage.
Match Aggregate to Purpose
Angular crushed stone for sub-bases (it locks under compaction), rounded gravel for drainage (water flows freely), fine sand for pipe bedding (protects pipes), decorative shingle for gardens. The wrong aggregate in the wrong place reduces performance and wastes money.
Compact in 75–100mm Layers
Never try to compact more than 150mm in one pass — the bottom of a deep layer will not achieve adequate compaction. Apply aggregate in 75–100mm lifts and compact each layer before adding the next. This is especially critical for load-bearing sub-bases.
Check Moisture Before Compacting
Granular aggregate compacts best at optimum moisture content — not bone dry, not waterlogged. Dry material can be lightly wetted before compaction with a hose. Saturated or frozen ground should not be compacted — wait for it to drain or thaw first.
Use a Geotextile Membrane
Always lay a permeable geotextile fabric over prepared subgrade before placing aggregate. This prevents fine soil particles migrating upward into the aggregate (called ‘pumping’), which destroys drainage capacity and reduces bearing strength over time — a common cause of driveway failure.
Verify Supplier Bulk Density
Bulk density varies between quarries. The values in this guide are industry reference figures. For large orders over 20 tonnes, ask your supplier for their specific material’s bulk density certificate to ensure your weight and cost estimates are accurate.
Check SuDS Requirements in 2026
From 2024 onwards, new driveways in England over 5m² must incorporate sustainable drainage (SuDS). Permeable bound aggregate or gap-graded open paving systems may be required. Check with your local planning authority before ordering. SeeSUSDRAIN.orgfor 2026 guidance.
Confirm Access for Delivery
A standard tipper truck carrying 14–20 tonnes is large and heavy. Confirm the delivery route, road surface, turning space, and any weight restrictions on residential roads before ordering bulk aggregate. For tight access, bulk bags (850kg each) or smaller 6-tonne tippers may be more practical.
Aggregate Unit Conversion Reference
Quick conversion formulas for switching between metric and imperial units when ordering or specifying aggregate quantities.
Millimeters → Meters
m = mm ÷ 1,000
Example: 150mm ÷ 1000 = 0.15m
Kilograms → Tonnes
t = kg ÷ 1,000
Example: 3,200 kg ÷ 1000 = 3.2 t
Feet → Meters
m = ft × 0.3048
Example: 12 ft × 0.3048 = 3.658 m
Inches → Millimeters
mm = in × 25.4
Example: 6 in × 25.4 = 152.4 mm
Cubic Meters → Cubic Yards
yd³ = m³ × 1.308
Example: 5 m³ × 1.308 = 6.54 yd³
Tonnes → Kilograms
kg = t × 1,000
Example: 7.5 t × 1000 = 7,500 kg
Cubic Yards → Cubic Meters
m³ = yd³ × 0.7646
Example: 8 yd³ × 0.7646 = 6.117 m³
Meters → Feet
ft = m ÷ 0.3048
Example: 10 m ÷ 0.3048 = 32.81 ft
kg/m³ → lb/ft³
lb/ft³ = kg/m³ × 0.0624
Example: 1600 × 0.0624 = 99.8 lb/ft³
Aggregate Standards & Regulations for 2026
Key British, European, and international standards that govern aggregate specification, testing, and use in construction — updated for 2026.
BS EN 12620:2013+A1:2022
The primary European standard for aggregates used in concrete production. Covers grading, shape, strength, and durability requirements for both coarse and fine aggregate. Mandatory for structural concrete in the UK and EU.
BS EN 13242:2002+A1:2007
Specification for unbound and hydraulically bound mixtures used in civil engineering work and road construction — including crushed stone, gravel, and recycled aggregate for sub-base applications.
UK Highways Series 600 (MCHW)
The Manual of Contract Documents for Highway Works specification for granular sub-base materials. Type 1 MOT must comply with Series 600 Table 6/1. Essential reference for road and driveway sub-base design.
BS 8500-1:2023 (Concrete)
The complementary British Standard to BS EN 206 for concrete specification. Covers aggregate requirements, exposure classes, and minimum/maximum aggregate sizes for different concrete applications in the UK.
BS EN 1610:2015 (Drainage)
European standard for the construction and testing of drains and sewers. Includes requirements for aggregate pipe bedding materials, granular surround specifications, and trench backfill procedures.
WRAP Recycled Aggregate Guidance
WRAP (Waste Resources Action Programme) publishes quality protocols for the use of recycled crushed concrete and mixed recycled aggregate in UK construction, helping projects meet planning sustainability requirements in 2026.
Aggregate Prices & Cost Estimation Guide 2026
Typical UK bulk aggregate prices for 2026 (delivered, per tonne). Prices vary significantly by region, order volume, and supplier. Always obtain 3 quotes for large orders.
- Aggregate Type: Type 1 MOT Crushed Stone; UK Price 2026 (per tonne): £28 – £42 /t; Bulk Bag (~850kg) Price: £55 – £80; Notes: Most economical sub-base choice
- Aggregate Type: 20mm Gravel (Natural); UK Price 2026 (per tonne): £32 – £50 /t; Bulk Bag (~850kg) Price: £60 – £90; Notes: Widely available across UK
- Aggregate Type: 10mm Pea Gravel; UK Price 2026 (per tonne): £35 – £55 /t; Bulk Bag (~850kg) Price: £65 – £95; Notes: Higher cost due to small particle size
- Aggregate Type: Sharp Sand; UK Price 2026 (per tonne): £30 – £48 /t; Bulk Bag (~850kg) Price: £58 – £85; Notes: Concrete and screed grade
- Aggregate Type: Decorative Shingle / Gravel; UK Price 2026 (per tonne): £45 – £90 /t; Bulk Bag (~850kg) Price: £75 – £130; Notes: Higher cost for washed, decorative grades
- Aggregate Type: Crushed Limestone; UK Price 2026 (per tonne): £28 – £44 /t; Bulk Bag (~850kg) Price: £55 – £80; Notes: Cost-effective, UK widely available
- Aggregate Type: Recycled Crushed Concrete; UK Price 2026 (per tonne): £14 – £26 /t; Bulk Bag (~850kg) Price: £35 – £60; Notes: 40–60% cheaper than virgin aggregate
- Aggregate Type: Granite Aggregate; UK Price 2026 (per tonne): £38 – £58 /t; Bulk Bag (~850kg) Price: £70 – £105; Notes: Premium price for premium durability
Aggregate Glossary – Key Construction Terms Explained
Understand the terminology used by aggregate suppliers, engineers, and contractors.
Bulk Density (kg/m³)
The mass of aggregate per unit volume including the air voids between particles. Used to convert volume (m³) into weight (kg or tonnes) when ordering. Always lower than the actual particle density (solid density).
Coarse Aggregate
Aggregate particles retained on a 4.75mm sieve — typically 10mm, 20mm, or 40mm gravel or crushed stone. Forms the structural skeleton of concrete and provides compressive strength to the mix.
Fine Aggregate
Particles passing through a 4.75mm sieve — essentially sand. Fills voids between coarse particles, improves workability of concrete and mortar, and contributes to surface finish quality.
Sub-Base
A compacted layer of aggregate placed between the natural subgrade and the pavement surface. Provides load distribution, drainage, and a stable working platform. Critical to the long-term performance of any paved surface.
Compaction
Mechanical densification of aggregate using a vibrating plate compactor, roller, or wacker plate to remove air voids. Proper compaction is essential — poorly compacted sub-bases are the number one cause of premature driveway and pavement failure.
Type 1 MOT (Hardcore)
Graded crushed stone (0–40mm) specified for sub-base construction to UK Highways Agency Series 600 standard. The most widely used sub-base material in the UK, providing excellent compaction and load-bearing characteristics.
Geotextile Membrane
A permeable synthetic fabric placed between subgrade and aggregate to prevent soil contamination and migration of fines into the aggregate layer (pumping), while allowing water to drain freely. Essential for long-term drainage performance.
Grading / Particle Size Distribution
The range of particle sizes within an aggregate sample, determined by sieve analysis. A well-graded aggregate contains a range of sizes that achieve higher packing density and better compaction than single-size material.
Void Ratio
The ratio of void volume (air + water spaces) to the volume of solid particles. A lower void ratio after compaction indicates higher density. Typically 25–40% before compaction, reducing to 15–25% after.
PSV – Polished Stone Value
A measure of an aggregate’s resistance to polishing under traffic. High PSV (above 60) is required for road surfacing aggregates where skid resistance is critical. Basalt and granite typically have higher PSV than limestone.
SuDS – Sustainable Drainage Systems
Drainage approaches that manage surface water run-off at source. In 2026, SuDS compliance is required for most new driveways in England. Permeable aggregate surfaces are a common SuDS solution for residential and commercial projects.
Blinding Layer
A thin layer (25–50mm) of fine sand or concrete applied over a sub-base to create a smooth, level surface for the damp-proof membrane and reinforcement before pouring a concrete slab. Prevents piercing of the DPM by sharp stones.
Frequently Asked Questions – Aggregate Guide (2026)
Answers to the most common questions about estimating and ordering aggregate for construction and landscaping projects.
How much aggregate do I need per square meter?
It depends on depth. At 100mm, 1 m² requires 0.1 m³ of aggregate — approximately 160 kg (0.16 tonnes) at a density of 1,600 kg/m³. At 150mm, that increases to 240 kg (0.24 t/m²). Use the guide above to get exact figures for your specific dimensions and aggregate type. Remember to add a 10% compaction buffer to your order.
What is the difference between tonnes and cubic meters of aggregate?
Cubic meters (m³) measure volume — how much space the aggregate occupies. Tonnes measure mass (weight). The relationship between them depends on the aggregate’s bulk density. For standard crushed stone at 1,600 kg/m³: 1 m³ = 1.6 tonnes. For granite (1,800 kg/m³): 1 m³ = 1.8 tonnes. Most UK suppliers sell aggregate by the tonne, so converting volume to tonnes is essential for ordering correctly.
How deep should a gravel driveway be in 2026?
For a residential driveway in 2026, the recommended specification is: 150mm compacted Type 1 MOT sub-base + 50mm compacted sub-base grit + 50–75mm finished gravel surface = total depth of 250–275mm. For light use (pedestrians and small cars), a simplified 100–150mm compacted sub-base with 50mm gravel topping may suffice. Driveways over 5m² in England now require SuDS-compliant permeable drainage — check with yourlocal planning authoritybefore starting.
How many tonnes of aggregate fit in a tipper truck?
A small 6-wheel tipper carries 8–10 tonnes. A standard 8-wheel tipper carries 14–18 tonnes. An articulated tipper can carry up to 26 tonnes. For smaller quantities under 2 tonnes, aggregate is also available in bulk bags (approximately 800–1,000 kg per bag) for drop deliveries where large vehicles cannot access. Always confirm the vehicle type and confirm site access is suitable before ordering.
What aggregate should I use under a concrete slab?
For a residential concrete slab sub-base, use Type 1 MOT or equivalent well-graded crushed stone at 100–150mm compacted depth. Top with a 25–50mm sharp sand or concrete blinding layer to provide a smooth surface for the DPM and reinforcement. Do not use topsoil, soft fill, or clay-contaminated material — these will settle and cause the slab to crack. For the concrete slab itself, use ourConcrete Volume Guide.
Does aggregate compact significantly after laying?
Yes — aggregate typically compacts by 10–25% depending on the material, layer thickness, and compaction equipment used. Type 1 MOT can compact by up to 20%. This is why you should always estimate the loose (pre-compaction) depth and then add a 10–15% buffer when ordering. Trying to compact more than 150mm in one pass results in poor density at depth — always compact in 75–100mm layers for best results.
Can I use recycled aggregate as a sub-base in 2026?
Yes, and it is increasingly common and encouraged. Recycled crushed concrete (RCA) meetingWRAP quality protocolsand BS EN 13242 can be used as a sub-base for driveways, footpaths, and non-structural applications. It is 30–50% cheaper than virgin aggregate and has a significantly lower carbon footprint. It should not be used in structural concrete mixes without specific engineering approval. Estimate the same way as standard aggregate — just use the correct recycled aggregate density of 1,200–1,500 kg/m³.
How is aggregate measured and sold by suppliers?
In the UK and Pakistan, aggregate is sold by the tonne for bulk deliveries (6–26 tonne tipper loads), by the bulk bag (approx. 800–1,000 kg) for smaller quantities, or by the 25kg and 50kg bag for very small amounts. Prices are always per tonne. Some suppliers also quote loose by the cubic meter (m³) — always clarify which unit they are quoting in. This guide gives you both m³ and tonnes so you can compare supplier quotes accurately.
How do I estimate aggregate for an irregular or circular area?
For irregular areas: divide the total area into rectangles and right triangles, estimate each section separately using the guide, then add the volumes and weights together. For a circular area: use the formula Area = π × radius² (e.g. a 3m radius circle = 3.14159 × 9 = 28.27 m²), enter this as Length × Width (e.g. 5.32 × 5.32 ≈ 28.3 m²) as an approximation, or use a circular area guide first to get the area in m², then multiply by depth and density manually.
What aggregate do I need for a soakaway or French drain?
Use clean, single-size, washed gravel — typically 20mm or 40mm rounded gravel with no fines. The gravel must be washed (no silt or clay fines) so that voids remain open for water storage and passage. Never use crushed stone with fines (like Type 1 MOT) in drainage applications — the fine particles will clog the voids immediately and the drain will fail. Line the soakaway pit with a geotextile membrane to prevent soil ingress. For soakaway design guidance, see theUK Planning Portal.