Tarmac Patching

It's a sad fact that a patch in tarmac, like many other drive surfaces that are laid wet, will almost certainly show up as a patch, whatever you do. But there are a number of methods of patching tarmac though and it's certainly cheaper than relaying the whole surface.

Pre-Mixed Tarmac For Smaller Holes

For patching small holes the DIY householder is probably better off using pre-mixed bags of tarmac available from builders' merchants. Although this is more expensive per square metre and you won’t get as good a finish as with proper tarmac, you won’t have all the mess and fuss associated with manipulating hot tarmac.

The pre-mixed tarmac is blended with a retardant that prevents the tarmac from setting and exposure to the air kicks off the setting process. It's best to allow the bags to warm up before they are opened as it helps the tarmac flow. No need for blowtorches or anything like that, just leave them in a warm room for a few hours or overnight.

Clean out the holes to be patched, removing any loose material and moisture. Then pour the tarmac mix in, tamping down and levelling in the same way as ordinary tarmac. Because of the retardant, which takes a while to evaporate, the patch will take a number of weeks to harden properly and even then may not be as hard as the surrounding surface, so take care with sharp pointed objects.

Larger Jobs

The second method of repair is, of course, to get proper tarmac in. This will almost certainly be cheaper and more worthwhile for a series of patches or a larger area.

With big holes you should cut out a rectangular area surrounding the patch using a power saw. Then chip out the remaining old tarmac with a cold chisel or bolster, or with a jack-hammer for a larger area. The sides of the hole should then be treated with cold pour, a jointing compound, to keep water out of the exposed areas.

Hot tarmac can then be spread into the hole and levelled with a heavy roller, which can be hired for the day if necessary.

Getting Hold of Hot Tarmac

The biggest problem is likely to be getting the tarmac. A delivery of a small amount of tarmac can be prohibitively expensive, as suppliers prefer to carry full loads. You could spread the cost by coordinating with neighbours who need to patch their drives, but all of them must be ready to take the tarmac when it arrives, so they will need to commit to doing all the initial preparation on the day.

If you are lucky you might find a local supplier who will load an amount into a trailer or pickup for you to take home and apply. If you do this, apart from the fairly obvious point that you should line the load bed to avoid the tarmac messing it up for ever, you will need to cover it with tarpaulin and old blankets or sacking to keep it hot during the homeward journey.

Keep Off!

With both methods if you can keep cars and feet off the area for a while then so much the better. This will prevent tarmac and aggregate sticking to them and being spread around the rest of the drive and into the house.