How thick should asphalt be for a domestic driveway?

For a standard domestic driveway, the typical construction is 50-60mm of binder course (base layer) topped with 25-30mm of surface course (wearing layer), giving a total asphalt thickness of 75-90mm. This sits on top of a compacted sub-base of 150-200mm of MOT Type 1 aggregate. Heavier use driveways may need thicker layers.

What is the difference between surface and binder course asphalt?

Surface course (previously called "wearing course") is the top layer you walk and drive on. It uses finer aggregate (6-10mm) and has a higher bitumen content for a smooth, durable finish. Binder course (previously called "base course") sits underneath and uses coarser aggregate (20mm) to provide structural strength. The binder course is slightly less dense at 2.3 t/m3 compared to 2.4 t/m3 for surface course.

How much does asphalt weigh per square metre?

At a typical 25mm depth, surface course asphalt weighs approximately 60kg per square metre. At 50mm depth, it weighs around 120kg per square metre. Binder course is slightly lighter at approximately 115kg per square metre at 50mm depth. These figures help when estimating delivery requirements.

Can I lay asphalt myself or do I need a professional?

While small repairs (pothole filling, patch repairs) can be DIY, laying a new asphalt driveway is best left to professionals. Asphalt must be laid and compacted while hot (above 130 degrees C), requiring specialist plant and equipment. A professional team can typically lay a standard driveway in one day.

Asphalt Calculator

Calculate tonnes of asphalt for driveways and roads

Published by UltraCalculatorsLast reviewed: 29 Mar 2026v1.0Sources:Highways England - Design Manual for Roads and Bridges BS 594987 - Asphalt for roads and other paved areas Mineral Products Association (MPA)Report an issue

Asphalt (commonly called tarmac in the UK, though technically a different product) is the material of choice for driveways, car parks, and roads. It provides a smooth, durable, all-weather surface that can last 15 to 25 years with proper installation and maintenance. Getting the tonnage right before ordering is essential, because asphalt must be laid while hot and any shortfall means an emergency top-up delivery or an incomplete job. Asphalt is a composite material made from aggregate (crushed rock) bound together with bitumen (a petroleum-based binder). It comes in two main grades for construction: surface course and binder course. Surface course is the top wearing layer with finer aggregate, while binder course sits underneath and provides structural strength. For most domestic driveways, both layers are needed to meet BS 594987 standards. This calculator estimates the tonnage of asphalt required based on your area, depth, and layer type. It includes a 5% waste factor to account for edge trimming, compaction loss, and material left in the delivery vehicle. Results are shown in tonnes (how asphalt is sold in the UK) and lorry loads (standard 20-tonne capacity).

How to Use This Calculator

To calculate your asphalt requirements: 1. Enter the area in square metres. For a rectangular driveway, multiply length by width. For irregular shapes, calculate the bounding area and add a few extra percent to the waste allowance. 2. Enter the depth in millimetres. For surface course only, 25-30mm is typical. For binder course only, 50-60mm is standard. When selecting "both," enter the binder course depth and the calculator adds a 25mm surface course automatically. 3. Select the layer type. Choose "surface course" for resurfacing an existing sound base, "binder course" for the structural base layer, or "both" for a complete new installation. 4. Review the results. The calculator shows surface course tonnes, binder course tonnes, total tonnes, and the number of 20-tonne lorry loads needed. All figures include a 5% waste factor. 5. When ordering, discuss your requirements with the asphalt supplier. They can advise on the correct grade and confirm delivery logistics. Asphalt is temperature-sensitive; it must be laid above 130 degrees C, so plan delivery timing carefully.

How It Works

The asphalt calculation uses area, depth, and layer-specific densities: For surface course: Volume (m3) = area (m2) x depth (mm) / 1000 Tonnes = volume x 2.4 (surface course density) x 1.05 (5% waste) For binder course: Volume (m3) = area (m2) x depth (mm) / 1000 Tonnes = volume x 2.3 (binder course density) x 1.05 (5% waste) For both layers: Surface: area x 0.025 (25mm) x 2.4 x 1.05 Binder: area x (depth/1000) x 2.3 x 1.05 Total = surface + binder Lorry loads = ceiling(total tonnes / 20) The density difference between surface (2.4 t/m3) and binder (2.3 t/m3) course reflects the different aggregate sizes and bitumen content. Surface course uses finer aggregate with more bitumen, making it slightly denser.

Worked Examples

Example 1: Resurfacing a driveway (surface course only)

Inputs: Area: 30 m2, Depth: 50 mm, Layer: Surface course

Volume: 30 x (50/1000) = 30 x 0.05 = 1.5 m3.
Weight before waste: 1.5 x 2.4 = 3.6 tonnes.
With 5% waste: 3.6 x 1.05 = 3.78 tonnes.
Lorry loads: ceiling(3.78 / 20) = 1 load.

Result: You need 3.78 tonnes of surface course asphalt, delivered in 1 lorry load. For a project this size, a single delivery is sufficient. Ensure the existing base is clean and a tack coat is applied before laying.

Example 2: Complete new driveway (both layers)

Inputs: Area: 30 m2, Depth: 50 mm (binder), Layer: Both

Surface course: 30 x 0.025 x 2.4 x 1.05 = 1.89 tonnes.
Binder course: 30 x 0.05 x 2.3 x 1.05 = 3.62 tonnes.
Total: 1.89 + 3.62 = 5.51 tonnes.
Lorry loads: ceiling(5.51 / 20) = 1 load.

Result: You need 5.51 tonnes total: 1.89 tonnes surface and 3.62 tonnes binder. Both can be delivered on a single lorry (often as a "split load" with binder loaded first). The binder course is laid and compacted before the surface course.

Example 3: Small car park surface course

Inputs: Area: 500 m2, Depth: 75 mm, Layer: Surface course

Volume: 500 x 0.075 = 37.5 m3.
Weight before waste: 37.5 x 2.4 = 90 tonnes.
With 5% waste: 90 x 1.05 = 94.5 tonnes.
Lorry loads: ceiling(94.5 / 20) = 5 loads.

Result: You need 94.5 tonnes of surface course, delivered in 5 lorry loads. For a project this size, coordinate deliveries to arrive at regular intervals so the laying team can maintain consistent progress without material cooling in the lorry.

Asphalt work in the UK is best done between April and October when ambient temperatures are higher, allowing longer working time before the material cools. The minimum laying temperature is around 130 degrees C; below this, the asphalt cannot be properly compacted. A standard domestic driveway (30-40 m2) can typically be laid in a single day by a professional team with a roller and hand tools. Always ensure the sub-base is properly prepared (150-200mm of compacted MOT Type 1 for driveways) before any asphalt is laid. Asphalt prices in the UK typically range from 70 to 120 pounds per tonne depending on grade and location, with delivery charges on top. For the best result, hire a contractor who is a member of the National Federation of Builders or has SafeContractor accreditation. Get at least three written quotes and check references before committing.