GROUND PREPERATION / EARTH WORKS
There are three key factors to consider before the process of cabro laying can begin. Firstly, is the compactness of the soil surface, the ground levels for surface runoff (water management) then lastly is edge restraining. Here’s how to install cabro paving blocks
How to install cabro paving blocks: SOIL STABILIZATION:
I am sure that by now most of you have witnessed firsthand ponding, sinking and even coming off of cabro blocks after installation. The key cause for this occurrence is normally how compact / firm the ground surface was before installation.
The soil type determines How to install cabro paving blocks. The best soil types to use for preparing the base are fine murram, murram mix locally known as “mchongo” and bluestone hardcore. In the event the ground has red soil or cotton soil, then excavation is required up to 300mm/1 foot in depth as a minimum for red soil while that for cotton soil can go past 300mm depending on how deep your pocket can go. In fact, for cotton soil if you are in the position to then full excavation and dumping comes highly recommended.
Now after the foot of soft soil is excavated & carted away or dumped, we then bring in and backfill the excavated void with the stable materials mentioned above to recap: fine murram, mchongo and bluestone hardcore. The area also determines how to install cabro paving blocks. For residential areas with light vehicular traffic, the mchongo and fine murram will do just fine. However, for commercial spaces with high or heavy vehicle traffic, the bluestone hardcore is recommended. It should be hand packed and compacted in two layers of 150mm. (see image above)
Soon after the backfill process is complete, water is then poured over the levelled surface and left to soak overnight. To master how to install cabro paving blocks, you should understand that the soaking only applies only where the murram mix and fine murram have been used as it helps reduce air pockets in between the soil particles.
Lastly, a roller is mobilized to site to compact the surface. As the roller moves over the ground surface it removes pockets of air while at the same time levelling the surface. Now you might be asking what size of roller do i need for my compound? A roller is chosen based on the size of vehicles that will be passing over the surface. For example: for small personal cars we use a 2t pedestrian roller to get the job done whereas for high or heavy traffic areas we recommend a 7t double drum roller.
When all these is achieved then the ground is considered firm and compact and that’s the first step on how to install cabro paving blocks.
As you move along on how to install cabro paving blocks, Ground levels are key to ensuring the longevity and durability of cabro paving blocks on your driveways and parkings. Why? This is because once cabro blocks are laid over the ground surface the water no longer percolates and seeps into the earth. Instead, once laid the ground becomes rigid (hard) with rainwater only moving over the surface and not underneath.
Now in order to avoid a flooding or ponding situation we need to ensure the water runs off the surface faster than it is being collected then disposed into a storm water drain or simply just outside the gate and onto the main road where it will always find its way.
In order to achieve this, we will need to create a gradient where one point is higher than the other. The point of outlet should be of a lower level than any given point of the compound. A simple cut and fill of the ground should be able to help you achieve this difference in levels.
Lastly, in many instances we may be required to confirm the difference in levels since just the use of the human eye only is not sufficient to guarantee sufficient slope for water flow. It is here that the use of a hosepipe level comes in place for residential compounds and as for commercial areas survey equipment such as a theodolite or transit level.
After the ground has passed the firmness and surface runoff levels tests, it then goes through a final step where we check if there are edged to hold the cabro blocks securely in place. This is an important step on how to install cabro paving blocks. By edges we are referring to where the cabro blocks terminate at the sides after they are laid.
Common example of edges are namely: a perimeter wall , a verandah edge , the sides of a house , a kerbstone (road kerb) or a road channel . These are key to ensuring that the cabro blocks do not come off when the wheel of a car turns or when a lot of surface runoff water from rain flows. The edge restraining also helps demarcate the paved side from the flower / green areas.
When these 3 key factors above have been achieved we can now say that the ground is ready to receive the cabro paving blocks. Now you know How to install cabro paving blocks and we’ll explore more on the next part.