Tarmac Driveway Installation Guide

A professionally installed tarmac driveway can last upwards of 20 years. Modern "SMA" (Stone Mastic Asphalt) mixes now offer even greater resistance to scuffing and stone loss, providing a sleek, jet-black finish that significantly boosts kerb appeal.

What Does the Work Involve?

• Site Excavation: Removing the existing surface and digging down to a depth of approximately 200mm–250mm to ensure a stable foundation.
• Sub-base Installation: Laying and compacting a thick layer of MOT Type 1 crushed stone to provide structural integrity and prevent sinking.
• Edging Restraints: Installing concrete kerbs, block paving borders, or metal edgings to keep the tarmac contained and prevent lateral spreading.
• Drainage Provision: Fitting linear drains (Aco drains) or soakaways to ensure the driveway complies with UK surface water regulations.
• Base Course: Applying a thick layer of larger-aggregate tarmac (usually 20mm) to provide the primary strength.
• Wearing Course: Laying the final, finer-textured tarmac layer (6mm–10mm) and compacting it with a heavy vibrating roller for a smooth finish.

Typical Costs

Prices for tarmac driveways are generally calculated per square metre. Total costs will vary based on whether you are "overlaying" an existing surface or requiring a full "dig-out" and new sub-base.

Factors affecting the price include the distance from the asphalt plant, the complexity of the driveway shape, and the necessity for significant groundworks or tree root removal.

How Long Does It Take?

• Small Driveway (Resurface): 1 day. Minimal preparation required before the final pour.
• Standard Driveway (Full Install): 3–4 days. This allows for excavation, sub-base compaction, and two-stage laying.
• Large/Complex Projects: 5–7 days. Usually involves significant drainage work or intricate decorative edging.
• Curing Time: You can usually walk on it after 24 hours, but vehicles should be kept off for 48–72 hours depending on the temperature.

DIY or Professional?

Tarmac installation is not a DIY project. It requires heavy machinery, including excavators and vibrating rollers, and the material must be laid while hot (around 140°C) to bond correctly.

Professional installers have the "hot-lay" accounts at local plants; DIYers are usually restricted to "cold-lay" bags, which are only suitable for temporary pothole repairs and will not last as a full driveway surface.

Choosing the Right Tradesperson

• Look for contractors who are members of the Marshalls Register or similar trade bodies.
• Ensure they have public liability insurance of at least £2 million.
• Red Flag: Be wary of "door-knockers" claiming to have "leftover tarmac" from a nearby road project; this is a common scam using inferior materials.
• Question: "How deep will the MOT Type 1 sub-base be?" (It should be at least 150mm for a standard driveway).
• Question: "Are you SuDS compliant?" (They must explain how water will drain off the surface).
• Question: "Do you provide a written guarantee against sinking or cracking?"

UK Regulations

• SuDS (Sustainable Drainage Systems): Since 2008, you must have planning permission to lay a non-permeable driveway over 5 square metres unless the water drains into a lawn, flowerbed, or soakaway.
• Dropped Kerbs: If you are creating a new access point across a public footway, you must apply for permission from your local council and use an approved contractor.
• Part V Building Regs: Ensure any new driveway does not create a trip hazard or impede access for people with disabilities.

Common Problems

• Scuffing: Turning car wheels while stationary on fresh tarmac can cause "power steering scuffs." Avoid full-lock turns for the first few months.
• Puddling (Birdbaths): Caused by poor levelling during the laying process. This indicates a failure in the base or wearing course.
• Weed Growth: Usually happens from the edges or through cracks if the sub-base wasn't treated with weedkiller or a geotextile membrane.
• Cracking: Often the result of an insufficient sub-base or heavy vehicles (like delivery lorries) using a driveway designed only for cars.

Frequently Asked Questions

Can I tarmac over my old concrete driveway?

Yes, provided the concrete is stable and not badly cracked. An "overlay" involves cleaning the concrete, applying a tack coat (glue), and laying a new tarmac skin, though this will raise the height of your driveway.

Is red tarmac more expensive than black?

Yes, red tarmac is significantly more expensive. The pigment and clear binder required can increase material costs by 20% to 50% compared to standard black bitumen.

How long does a tarmac driveway last?

With a proper sub-base and professional installation, you can expect a lifespan of 15 to 20 years. Regular sealing every few years can extend this further.

Do I need planning permission for a tarmac drive?

Only if the surface is non-permeable and the water drains onto a public highway. If you install a soakaway or drain the water into your own land, you generally do not need permission.

Why is my new tarmac driveway "soft"?

Tarmac stays flexible for several months, especially in summer. It takes time for the oils to evaporate and the binder to fully harden. Avoid using ladders or high-heels on it during very hot days.