Farm roads range from fully tarred roads built by qualified engineers to temporary dirt tracks created using small tractors.
Farms of all types and sizes depend on suitable roads so farmers can manage their land and run effective businesses – and in some cases, farmers are even being compensated by the South African government for taking matters into their own hands and fixing stretches of municipal road.
Here we offer a simple overview of the main steps involved in building and maintaining a farm road.
For much more detailed information on how to build a road, see this comprehensive guide from Forest Engineering South Africa. The guide is designed for forest roads but includes masses of useful information that’s relevant for all types of farm roads too.
Analyse the lie of the land
Before you start building a road, take a close look at a topographical map of the land. Ideally, you want the road to follow the path of less resistance, and avoid large obstacles and steep gradients. Once you’ve determined a suitable course, map it out from start to finish.
Create a roadway
Create the road by driving the mapped route several times, preferably with a heavy farm vehicle. Once you have a discernible track, clear away all the debris. We recommend using a motor grader for the most efficient outcome.
Once the road is clear of rubble, remove a thin layer of the topsoil with the grader blade, and widen the road to around 3 to 5 metres. Ensure fences are no more than 45 cm from the edge of the road. That way, the road will have little impact on the available grazing or crop propagation land.
Lay the foundation
A good time to lay a new road is in dry conditions. The material is less likely to mix with the top soil. As you want the thoroughfare to be higher than the surrounding area, it’s best practice to lay a foundation layer consisting of crushed rubble, or some other granular fill material, ranging in dimension from 200 to 250 mm.
At this stage, the intended slope of the road must be formed, and the material properly compacted with a drum or vibratory roller.
Grade the slope
The crossfall, or slope, of a road ensures water drains away from the surface.
There are two ways of sloping a road – by grading a crown in the centre of the road, with crossfalls on either side, or by creating a road which slopes in only one direction.
Out- or in-sloped roads are more suitable for temporary applications, and in locations where grades are 10 percent or less. Crowned roads function optimally in all conditions and locations, and are easier to maintain.
There are instances when the use of both sloping techniques is appropriate. On straight sections, a crowned slope with a crossfall of 5% on both sides is best practice. On curves, the slope is applied on only one side of the road.
Tip: You can find information on cut and fill slopes, minimum curve radius, and any other elements of road design and construction, in the South African Forest Road Handbook, a guide that applies equally to farm roads.
Lay the road surface
Once the required slope has been created, it’s time to lay the road surface. Shale and sandstone dust, or any other fine material with a diameter of between 40 and 60 mm, is suitable. Spread it evenly across the road to maintain the crown and slope, and compact the material.
Cut drainage ditches
Water that does not drain away from the road can degrade the surface, and create potholes, ruts and corrugation.
By cutting drainage ditches, 30 cm wide and 30 cm deep, on either side of a crowned road, and building water diversion ramps to lead water from one side of the road to the other, surface damage is kept to a minimum.
Maintain the road
Regular maintenance is required to remove excess loose material and rectify road defects. You can do this by dragging a heavy object, like a railway sleeper or iron beam, behind a bakkie or tractor.
Ensure the object is chained to the vehicle in such a way it follows at a slight angle to maintain the slope.
Streamline farm road maintenance: invest in a motor grader
If you want to build a farm road like a pro, and carry out routine maintenance with ease, a motor grader is the best investment you’ll ever make.
At KH Plant, we specialise in restoring Caterpillar 140G, 140H and 140K motor graders and components to as-new condition – so you can get the benefits of a new motor grader at a fraction of the cost of a new machine. Contact us for more information or to discuss your needs.
