The subject of driveway surfacing doesn’t come up in conversation very often – except after a storm if you live in a hilly locale with loose material on your driveway. Then you will most likely be staring unhappily at a pile of gravel, at either the top or bottom of your driveway and grousing about this to all your friends!

Gravel Driveways
I left the domain of concrete driveways decades ago and have been living with a gravel driveway ever since. There is more to creating a good gravel driveway than you think: ours took a couple of years to get it right. First the 50m length was graded with a grader not a bobcat. The grader driver formed the drive to include a central camber. Take a good look at any road – it is higher in the centre than the edges. This is called camber and allows the rain to be shed to the gutters rather than sitting around in puddles. This is a most important step and should not be neglected. Then the driveway was spread with road metal also known as blue metal or B grade crushed rock. This is gravel made from bluestone with an average size of between 10mm and 20mm. It is the cheapest gravel available in our area and contains some ‘fines’ (a small amount of clay and fine gravel) that helps to hold it all together. Every area of Australia has their own version; be it gravel made from bluestone, granite, sandstone, limestone, quartz or scoria (you could also use recycled crushed concrete/bricks in this situation). The use of river pebbles on a driveway is to be avoided. Pebbles are rounded and so never lock together in the manner of sharp edged gravels. They are difficult to walk on and get moved around a lot by car tyres. I know, because I grew up with a pebbled driveway!

Back to our driveway, after the blue metal was laid, it was then compacted with a roller and left for 12 months to stabilise. We could have chosen to have the last step to be done then and there, but as there was no hurry (and it gave us time to save up) we were advised that letting it sit was the best option. The last step involved spreading granitic sand (also called decomposed granite) on the driveway. In our area it is a pale sandy colour and complemented the honey tones of the weatherboards on our house. This was also rolled and little lumps and bumps smoothed out on the same day while it was still damp. Once granitic sand has dried out, it sets like concrete and it is very hard to change any levels, so the trick is to get it right the first time.

Our driveway has weathered the years very well and has never developed wheel ruts, although we have noticed that the ‘fines’ in the gravel tend to settle in the lower areas. These are very sticky after rain so we just learnt to avoid stepping in them. Potholes have developed where the car is consistently parked and these require special treatment. You can’t just throw some granitic sand in the holes because after the next rain it will just wash out. You need to scrape the holes back to the road metal, fill the hole with fresh road metal and compact it well (a car driven back and forth works okay) then you can top it off with a layer of the granitic sand also compacted.

You can also purchase some gravels pre-stabilised so they stick together and to the base better than the untreated product. Cement or lime is often added as a stabiliser. Its worth noting that there are also several products on the market for applying to a granitic sand driveway or path after it is laid, which helps with stabilisation. The best part of a gravel (ie porous) driveway is that water is generally held onsite soaking into the soil and thus reducing the load on our stormwater system. This is a very valid point in this day and age. With regard to weeds, I find that twice a year, spot applications of glyphosate takes care of the few weeds that appear.

Partly Sealed Driveways
The product called Grasscrete has come a long way since it was first invented in the 1970’s. Remember the small blocks of concrete in amongst a sea of grass? This was the first stab at trying to stabilise a surface for cars, yet still have the effect of lawn. The concrete takes the weight of the car allowing the grass to grow in uncompacted soil. There are now a range of options available and they are a great idea for allowing the rain that falls onsite to stay onsite. New products made from recycled plastic form an interlocking honeycomb structure and are laid on a bed of compacted gravel. We installed this in a pathway at our place and it has worked very well. This product can be used in driveways but will only look good if you have the water to keep the grass alive.

Sealed Driveways
If you have a gravel driveway and wish to seal it, there are a few options. Laying asphalt is a good way of solving loose gravel problems forever but requires a well-made and compacted gravel base to be created first. Asphalt is applied as a ‘hot mix’ (bitumen coated gravel is poured onto the drive, raked out and compacted) and you will have a classy smooth driveway that looks particularly good when edged with pavers. The cheaper option is to go for a bitumen ‘spray seal’ (hot liquid bitumen is sprayed onto a compacted gravel bed and then covered with a thin layer of gravel) but beware fly-by-night operators. A friend had a spray seal done on her driveway and it didn’t last, due in part to poor preparation. Both asphalt and bitumen come in a limited range of colours and is said to be cheaper than concrete.

If pouring a fresh concrete driveway, a stamp can be pressed into the wet concrete to give the appearance of crazy pavers, slate or clay/concrete pavers in various patterns and colours. If you already have a concrete driveway there is a lot you can do to change it (beyond concrete paint) as long as your concrete is in good condition. There are companies that specialise in the application of stencils which make the existing concrete look like it is actually pavers or slate in a range of colours.

Clay or concrete pavers look great on a driveway but again preparation is the key. You can lay pavers on a base of sand for a footpath, but for a driveway you really need to lay the pavers on concrete so you have double the cost paying for both concrete and pavers. An impervious driveway (bitumen, concrete or pavers) needs special attention paid to drainage. Strip drains can be laid across the driveway to catch surface flow, but this needs to be directed somewhere. Beware the steep slippery driveway after rain! Concrete and pavers can be sealed with a clear solution that contains very fine grit which helps stop you slipping.

Driveways are a necessary evil in my opinion. I look at mine and think of all the plants that could be grown in that space! Instead I have to reserve it for a car. I guess if we’d had boys if would have been used for cricket, but with girls it was the place to learn to ride a bike or run up and down with a kite. I guess there are some benefits to having a nice smooth drive after all!