Tarmac Driveways: Costs, Lifespan and What to Watch For

The correct build-up starts, as with any driveway, below ground. The area is excavated to formation level, a geotextile membrane is laid where the subgrade is soft, and a compacted layer of MOT Type 1 stone forms the sub-base — typically 150mm for domestic cars, more where vans or deliveries are expected.

On top of that goes the tarmac itself, and this is where the quality difference shows. A proper domestic drive has two layers: a base course of coarser material around 40 to 50mm thick, then a surface course of finer 6mm asphalt around 20 to 25mm thick. Both are rolled hot while still workable.

A single thin layer of surface course laid straight onto old ground or an existing failed drive is the hallmark of a cheap job. It will look immaculate for a season and then crack, ravel and pothole once frost gets underneath.

Per square metre, tarmac is usually the cheapest full driveway surface. The economics change with size: on a large area the material and plant costs spread efficiently, while on a small drive the fixed cost of mobilising a hot lay team and a roller dominates.

Against block paving, tarmac is generally cheaper to install and faster, but it lacks the decorative options and cannot be lifted and relaid for a repair. Against resin bound, tarmac is cheaper up front but is not permeable, so it needs a designed drainage solution to avoid planning issues on front gardens.

One useful middle path is a tarmac base with a block paved border and apron. The border gives a solid, attractive edge restraint and lifts the appearance considerably for a modest extra cost.

Tarmac is impermeable. Under English planning rules, a front driveway over five square metres surfaced in an impermeable material and draining onto the highway requires planning permission. The standard solution is to lay the drive with a slight fall towards a linear channel drain connected to a soakaway, or towards a gravel or planted border that can absorb the runoff.

Soakaways need to be sized for the area they serve and sited a sensible distance from foundations — generally at least five metres from the house. On the heavy clay found across much of central Essex, soakaways drain slowly, so they need to be larger than the same design would be on the sandier ground nearer the coast.

Getting this right at the design stage costs a modest amount. Retro-fitting drainage to a finished tarmac drive that ponds at the garage door is expensive and rarely tidy.

Ravelling — loose stones lifting from the surface within the first year — usually means the mix was laid too cold or was under-rolled. Once it starts, it accelerates, because every dislodged stone exposes more edges.

Roller marks, wavy levels and visible joint lines across the middle of a drive suggest the material was laid in patches as it cooled rather than in a continuous run. Small tarmac driveways should ideally be laid in one operation.

Edges that crumble away within a couple of years mean no edge restraint was installed. Tarmac has no lateral strength at its perimeter, so it needs either a kerb, a concrete haunching or a block border to hold it. An unsupported tarmac edge is the most common single defect we are asked to repair.

Finally, be wary of any driveway offered from a van with leftover material from another job. There is no legitimate scenario in which a properly planned tarmac drive produces enough surplus to surface someone's home.

Tarmac needs very little routine care. Keep it swept, clear leaves and moss from the edges where water sits, and deal with weeds growing at the perimeter before they widen a crack.

Petrol, diesel and engine oil dissolve bitumen, so spills should be soaked up with sand or cat litter and cleaned promptly rather than washed in. Where a vehicle habitually leaks, a small area of block paving or a drip tray under the engine bay saves the surface.

Avoid pressure washing tarmac at high pressure — it strips the bitumen film from around the aggregate and shortens the surface life. A stiff brush and a proprietary cleaner is enough.

Sealing is available and restores the deep black colour of a faded drive. It is cosmetic rather than structural, and it must be applied to a clean, dry, sound surface. Sealing over a failing drive simply hides the failure for a season.

Isolated potholes and cracks in an otherwise sound drive are worth cutting out and patching properly — saw-cut square edges, remove the failed material, check the base, and reinstate in two layers. A cold-pour patch tipped into a hole is a temporary measure at best.

Where the surface is cracked in an interconnected pattern across large areas, the base has failed and patching is money wasted. At that point an overlay is only viable if the levels still work and the existing surface is stable; otherwise a full dig-out is the honest answer.

If the drive needs replacing anyway, it is worth reconsidering the surface. Many Essex homeowners who originally chose tarmac for cost move to resin bound at replacement time because the base can often be reused, which closes much of the price gap.