Asphalt and tar surfacing quotes from local contractors

Asphalt, tar and chip seal: what you're being quoted for

Most South Africans say "tar" for any black road surface, but very little of it is tar any more. What gets laid on driveways today is almost always asphalt: crushed stone bound with bitumen, mixed hot and rolled flat. True coal tar has largely disappeared from road building. The word stuck; the material didn't.

That matters when you compare quotes, because different companies use the same words for quite different finishes.

Why asphalt rather than paving?

Asphalt goes down quickly over large areas, has no joints for weeds to grow through, and is usually cheaper per square metre than pavers once the area gets big: long driveways, estate roads and parking yards. It's also easy to sweep and to drive on straight away once it's been rolled and has cooled.

The trade-offs: it softens in strong summer heat, so heavy vehicles parked in one spot can leave dents; petrol and oil drips break down the binder over time; and patch repairs are visible. On a short driveway in front of the house, many owners still choose paving for looks. For a long or wide area, asphalt usually wins on cost.

What a good surfacing job looks like

As with paving, the surface is the last and thinnest part of the job. Asphalt is laid in a layer only a few centimetres thick, so it depends entirely on the base underneath for its strength.

• Base preparation. The existing ground is excavated, any soft material removed, and a layer of crushed stone or gravel is laid and compacted to support the weight of vehicles.
• Shaping for drainage. The base is shaped with a fall or a crown so water runs off the surface. Water standing on asphalt, or soaking into the base underneath, is what causes potholes.
• Priming or tack coat. A bitumen coat is sprayed before the asphalt goes down, so the new layer bonds to what's underneath.
• Laying and rolling. The asphalt arrives hot and has to be spread and rolled while it's still workable. A proper roller, not just a plate compactor, matters for anything larger than a small patch.
• Edges. Kerbs or a well-compacted shoulder stop the edges crumbling. Unsupported edges are where asphalt driveways start to break up first.

Resurfacing an existing driveway

If your tarred surface is cracked but not breaking up, it can often be overlaid with a new layer rather than dug out. If there are potholes, soft spots or areas that sink when you drive on them, the base has failed, and those sections need rebuilding before any new surface goes on. A new layer over a failed base will crack along the same lines within a season.

Ask each contractor to tell you which parts they plan to patch, which to dig out, and which to overlay. Quotes that simply say "resurface" for one price aren't comparable.