The ground at just about any building or work site has to be levelled before any work can begin. In this article, we offer a short guide to construction site grading in South Africa.
Effective grading depends on the right motor grader. At KH Plant, we specialise in rebuilding and selling Caterpillar 140G, 140H and 140K graders. Contact us to find out more.
Skip to section:
- Reasons for grading sites
- Types of site grading
- Steps in the construction site grading process
- Mistakes to avoid
- Equipment for construction site grading in South Africa
Reasons for grading sites
All types of construction sites need to have their ground prepared before work can go ahead. Construction sites might also need to be graded during construction to re-level the ground and removing any new obstructions.
Construction site grading helps…
- create a level and stable surface
- ensure effective drainage and prevent soil erosion
- ensure compliance with building codes and standards
- keep a site tidy and safe while work proceeds
- improve site functionality and aesthetics at the end of construction.
Types of site grading
Different types of grading may be distinguished based on the phase when the grading occurs or the purpose of the grading. Examples are:
- regrading
Regrading involves using a grader to raise or lower the ground underneath the construction site. It is used on both large and small construction projects.
- rough grading
Rough grading prepares the work site for construction by shaping the topography. This removes vegetation, debris and levels the soil.
- finished grading
Finished grading happens after rough grading. It refines the grading process and ensures proper levelling. It makes the ground functional and safe for construction.
- final grading
The final grade is the final preparation of the ground on the construction site. It usually involves finishing the surface with topsoil or sand.
- architectural grading
Architectural grading involves creating the necessary features on the site as specified by the plans. This may include retaining walls, terraces, drainage systems or steps.
- landscape grading
Landscape grading is altering the topography to create landscaping or aesthetic features such as garden beds, lawns, paths and other garden features.
Steps in the construction site grading process
The process for grading a construction area will differ somewhat depending on the state of the site and its size.
Generally though, construction site grading will follow these steps:
Step 1: Surveying the site
Surveying the site will provide an overview of the original topography as well as the location of any existing structures or obstacles.
Step 2: Developing a plan
The grading plan should outline the proposed changes to the site’s topography. It should include the position of any roads, drainage channels or building pads that will be created.
The plan should also include a report on the potential environmental impact and steps that will be taken to minimise damage.
Step 3: Obtaining permissions
You will need to make sure you have all the right permissions or permits from the local authorities before you go ahead.
Step 4: Clearing the site
The site will need to be cleared of any obstacles or existing buildings that are to be demolished. Obstacles could include trees, large boulders or dumped rubbish.
Step 5: Earthmoving
The major earthmoving to change the topography into the required layout should be done first. This will require heavy machinery such as bulldozers and excavators.
Step 6: Compacting and shaping
After shaping the topography, the surface of the site will need to be compacted to create a stable base to work on.
Step 7: Drainage
The necessary drainage must then be created to prevent damage and erosions from rain runoff. This should include drainage ditches, culverts, retaining walls etc.
Step 8: Final grading
The final grading will then create a smooth and stable surface that is ready for construction to start.
Step 9: Inspection and sign off
A professional engineer will then inspect the site to make sure it meets regulations and sign off on the grading job.
Mistakes to avoid when grading
At a planning level, some of the most basic (and common) mistakes to avoid when creating a site grading plan are:
- failing to check for updated codes and standards
Be careful not to rely on outdated versions of codes, standards or industry best practices.
For example, these may help determine grading requirements in relation to slope limits, erosion control, environmental impacts and stormwater management.
Failure to abide by the current codes can lead to expensive fines, delays or even project failure.
- communication failures
Holes in communication with the other parties involved in a construction project – from architects and civil engineers to contractors or the client – can be disastrous.
It’s vital to coordinate with other disciplines. When creating a grading plan, use agreed units of measurement and appropriate tools and methods, given stakeholders’ expectations.
Also ensure there’s a system for staying abreast of any specification updates or issues that arise.
Once a grading plan is in place, implementing it requires good communication with site management and staff, including grader operators.
- using inaccurate measurements
Make sure you take multiple measurements using the right equipment and have someone double-check them. Using inaccurate measurements is one of the most frustrating and readily avoidable mistakes when grading a site!
- relying on outdated site data
Don’t rely on old data or information. Make sure you have current information about the site’s topography and soil characteristics.
Of course, site grading also requires technical know-how and accuracy. The requirements will vary based on the purpose and nature of a project, and the condition of a site.
For commercial and residential construction sites, for example, professional grading helps protect building foundations by preventing the accumulation of groundwater.
This involves applying recommended standards regarding:
- the gradual downward angle of the ground away from building foundations, to promote drainage
- extension of building foundations to a specific height above ground, to help prevent the entry of groundwater.
Equipment for construction site grading in South Africa
Preparing a work site for construction requires specialised heavy machinery.
Examples of this equipment can include bulldozers, motor graders, compactors, skid steer loaders, excavators and more.
At KH Plant, we specialise in reconditioning Caterpillar motor graders. Our rebuilt graders offer the performance and durability of brand new graders – at a fraction of the price of new machines.
For a motor grader for construction site grading in South Africa, contact us to discuss your needs.