But how is it created?
The quick answer is "by adding colours and stamping moulds into freshly laid concrete". For more detailed information, read on...
Preparing The Ground
As with any paving project, the ground area needs to be properly prepared before any concrete can be poured. The existing surface is excavated to a depth suitable for the purpose of the paving and any debris is removed from site.
Following excavation, we will know what kind of sub base is available and an appropriate level of hardcore will then be added. This is then compacted to form a solid, level foundation on which to pour the concrete.
The preparation stage is also the time when any required remedial or alteration works to the drainage will done, along with the installtion of gate posts, manholes, steps, etc..
To provide a framework for the concrete to be poured into, temporary wooden barriers are then fitted around the perimeter.
Pouring The Concrete
The concrete itself is specially designed for pattern imprinting. It is air entrained and fibre enmeshed, meaning that whilst the concrete is setting (or curing), the fibres within it mesh together. This gives the whole slab much greater strength, making it up to 25% harder than standard concrete.
After pouring it to the required depth, the concrete is raked to ensure future rain water will flow in the desired direction and then floated to give a smooth, flat finish.
Whilst still wet, it is then ready for colouring and stamping.
Colouring The Concrete
Each colouring uses two agents which come in the form of a powder. Used together, these colouring agents help to create a textured two tone look upon completion.
Colour surface hardener (in your chosen colour) is distributed across the surface of the concrete by hand. Following which, the concrete is then re-floated, forcing the colour into the surface of the concrete.
The release agent, most often a darker colour, is then added over the coloured concrete ready for imprinting.
Imprinting / Stamping The Concrete
Interlocking moulded rubber mats with the selected pattern(s) are then used to stamp the concrete, creating a nice uniform finish. Starting at an edge or corner, we work our way across, standing on the mats as we go to imprint the concrete, thus avoiding directly stepping in it.
With imprinting complete, it is cordoned off overnight to avoid unwanted footprints.
Preparation For Sealing
Dependent on the weather, once dry, the surface of the concrete is pressure washed using detergents and release agent remover.
Once cleaned, "crack control joints" (also known as "expansion cuts") are created in the surface of the concrete using a diamond disc saw. Essential to reduce the likelihood of future cracking, with most patterns these cuts are barely visible.
Sealing The Concrete
Finally an acrylic sealant with anti-slip agent is applied. This protects the surface of the concrete and brings it to life, enhancing the colours beneath.
Want to know more? Why not contact Northern Cobblestone for driveways, garden paths or patios and you can see it in action.