In short
Yes, if the existing surface is sound. A tarmac overlay can go over old tarmac or concrete that is firm, well drained and not moving, and Pavingexpert puts the minimum overlay at 25mm, bonded to the old surface with a bitumen emulsion tack coat. If the old drive is cracked through, sinking or breaking up at the edges, an overlay copies those faults into the new surface within a year or two and the money is better spent on a dig-out.
This is a job for our Tarmac & Asphalt service.
What an overlay is
An overlay is a new surface course laid directly on top of an existing hard surface instead of digging it out. The old drive becomes the base. It is quicker, cheaper and less disruptive than a rebuild, which is exactly why it is offered when it should not be.
When it is the right job
- The old surface is firm. Walk it after heavy rain. If nothing rocks, puddles or feels soft underfoot, the base is probably doing its job.
- The faults are on the surface. Fading, fine crazing, a rough or fretted top and shallow wear are surface problems and an overlay solves them.
- The levels allow it. Adding 25mm or more raises the drive. There has to be room at door thresholds, garage doors, manhole covers and the damp-proof course. Pavingexpert's guidance is that the finished surface stays at least 150mm below the damp-proof course.
- The edges are held. Tarmac needs a restraint at its edge. If the old drive has none, we add one before overlaying.
When it is a false economy
- Cracks you can fit a coin into. These run through the base. An overlay bridges them for a season and then the crack reflects up through the new surface.
- Sinking or rutting. The ground or the sub-base has failed. Covering it changes nothing.
- Breaking up at the edges or around covers. The base has lost its support there and the new surface will do the same.
- Water sitting on it. Standing water means the falls are wrong or the drainage is not working. An overlay will not correct falls unless it is designed to, and it can make the puddle bigger.
What a proper overlay involves
We clean the old surface, cut out and repair any failed patches so the base is continuous, deal with the edges and any covers, apply a bond coat so the two layers act as one, then lay and roll the new course. Pavingexpert is clear that the overlay must be bonded to the existing surface, and a dry, unbonded overlay is the one that delaminates and breaks up in sheets.
How we decide on yours
We look at the drive rather than the photograph. If it will take an overlay we quote for one and write down the repairs it includes. If it will not, we tell you and quote for the dig-out instead. Overlaying a drive that is past it is the job we most often get asked to put right, so we would rather lose the small job than do it badly.