What is a burnished concrete finish?
Burnished concrete is the polished concrete finish where there is no aggregate exposed. Burnishing is the term applied to the finishing of concrete to provide a hard-wearing, durable finish with a surface lustre.
It differs from polished concrete in the way that it does not require as many steps.
What are the advantages of Burnished Concrete?
- Burnished finished concrete surface has durability and is extremely strong. It can easily withstand heavy foot and equipment’s load.
- Properly installed, sealed and maintained burnished concrete floor has a life span of more than hundred years.
- As the surface is smooth and even, maintenance is very easy. Care must be taken that dust does not accumulate on the surface.
- The properly finished surface is water resistant.
The two major types of burnish concrete are:
- Steel Trowel Burnishing
In this method, trowelling is used to obtain the required surface lustre. This can either be done by hand trowelling or mechanical trowelling. Many factors affect the burnishing process of concrete such as the time of concrete placement, slump, compaction, finishing techniques and curing.
These properties of concrete must be stringently ensured to get a consistent high-quality finish. The concrete strength should typically be at least 32 MPa to ensure sufficient fine material is available to achieve a good surface finish.
The steel trowel burnishing process typically requires a concrete slump of 80 to 100mm with a tolerance of 15-20mm. The desired outcome of burnishing is to achieve a smooth, impervious and durable surface, free of residual trowel marks.
- Wax or Resin Burnishing
In this type of burnishing, waxes and resins are used as toppings on the concrete floor to make the surface shine. Floor waxes, liquid polishes and resin-based coating applications can also be used to produce a burnished finish.
These are multi-layer applications which, after the recommended curing period, are burnished or polished using polishing equipment. The degree of lustre achieved is dependent on the quality of the concrete density, coating product and the burnishing technique.