Skip to content

How to Polish Concrete Worktops

Knowing the art of grinding and polishing concrete worktops is crucial for a successful project’s completion.

Concrete is made up composed of cement, rock aggregate, water, sand and. Cement is by itself extremely brittle. But when sand and rock aggregates are added to it, an aggregate is created that helps strengthen the mix. The cement acts as a glue and helps to fill in the tiny gap between aggregates and sand. This makes concrete more durable than cement on its own. Since the rocks used in concrete mixes is quarried locally, the types of rocks you will see differ based the region you’re within the planet. The concrete pieces included in this guide are made of an 8000 psi. concrete mix.

Typically, when casting concrete the cement paste creates an uniform layer on the surface of the object, creating an item that has a solid color that has minor variations. This is known as casting-finish. The cement layer is removed using a light polish. It will start to let the fine particles of sand within the mix. This is known as the light-polish. A more thorough polishing process will expose the aggregate rock and result in the appearance of a ground-finish. A small amount of material must be removed in order to expose the aggregate for an even ground (about 1/4 ”).

This guide will teach you ways to shine concrete worktops. There are many options for finishes that can be made from one slab of concrete. Polishing is usually done using an adjustable speed concrete polisher and diamond discs for sanding. The polisher is typically run by water and is connected to a regular garden spout. The water assists in cooling the pads and keeps dust to an absolute minimal.

Polishing concrete worktops – Step 1. Safety Information

The process of polishing concrete worktops isn’t risky, but electricity and water don’t blend well. If your polisher isn’t equipped with an Electric ground Fault Circuit Interrupter make sure you are cautious to stay clear of electrocution. Even using an GFCI it’s a great suggestion to put on rubber gloves to protect yourself.
Use a mask for particle protection if you’re performing any type of dry grinding. Concrete dust can be caustic.

Second Step – Finish Cast Light Polish Ground Finish

From just one slab made of cement, there is a variety of finishes can be made available based on how you polish and how deep .
Uniform finish – Concrete exhibits uniform colors because while it’s being formed it is covered with an extremely thin coating of cement is formed on the inner surfaces of the formwork.
Light Polish Once you begin to polish the surface the thin layer cement is removed while the fine, sand-like aggregate becomes visible.
Ground Finish – When you polish further into the concrete you expose the larger aggregates in the mix of concrete.

Step 3 – Grinding vs Polishing

Grinding can be described as the most rough way to flatten the concrete surface. Polishing involves bringing the concrete surface and polish it to a increasingly smooth, shiny, and polished surface.
In the case of precast concrete construction, it’s typically necessary to employ grinders. Since the formwork will do the majority of the shaping the only location you’d require the grinder is some part of the project that’s not visible (like the back of a worktop made of concrete).

  1. Variable Speed Polisher

A variable speed wet-polisher is a multi-faceted tool that can be used for any type of concrete, and is also able to be applied to stones or other glasswork.
The Alpha polisher used in this video uses normal power from the wall (110V in the USA) and must be connected to an GFCI. The GFCI breaks the circuit and will cut off power to the device if electrocution risk is present.
The water line feeds similar to a standard garden line and connects to the standard spout. The valve regulates the rate at which water flows through the middle of the arbor. In some polishers the water line feed can actually cool the bearings within the tool. Running it dry may cause the bearings.

Step 5 – Different types of polishing Pads

Soft Pads – You’ll need an adhesive backing made of rubber that is able to be screwed onto the polisher. Soft pads are ideal for those who are newer since they’re less prone to damage. They can also polish surfaces with contours. Most commonly, they are used in conjunction using a concrete polisher that is water-fed.
Rigid Pads need a quick-release mechanism that connects onto the polisher. They polish faster than soft pads. However, they also can scratch the surface if it isn’t firmly held flat. Most commonly, they are used in conjunction by the water-fed polisher.
Dry and Wet Pads They require a quick-release mechanism however, unlike other pads they’re safe to use with the high-speed angle grinder.

  1. Step 6: Wet Polishing Preparation

Get a clear idea of the goals you’re trying to reach before you begin the process of polishing. It’s always possible to take away additional material, but you won’t be able to return it and you must be careful.
Wear rubber gloves
Think about the possibility of wearing rubber gloves, and rubber boots.
Then, elevate the piece on Scrap 2” of foam.
Polish outdoors in shade, where possible, or in the indoors using an ironing table.
Make polishing tables (sloped table covered with plastic tarp and 6” high walls, drains of water to an empty plastic bin, pump to recycle water, plumbing to water valves for hoses).

Step 7 – First Polish

To finish a floor start with the lowest grade of pad available typically 60 grit. Polish the surface in a uniform manner until a uniform amount aggregate is visible, and then move on until the pad next.
For a lightly polished finish begin with a mid-range pad, for example, 300. It is possible to remove additional material, but it’s impossible to return to the previous level and you should be cautious not to begin at a lower level if you do not desire a complete polish.
Tape off the areas you don’t wish to polish using a couple of coats of masking tape.

Step 8 – What to Polish

Switch on the water source.
The polisher should be lifted above the surface, then switch the polisher on.
The polisher is lowered onto the concrete, and let the weight of the device perform the job. Make sure the pad is as flat as is possible.
The piece should be moved around in a uniform manner by making circular movements. Do not stop or start at one spot in a long time.
When you’ve got a huge area to be polished, concentrate on small areas rather than trying to complete all at once.
Proceed to the next pad after the surface has been uniformly polished.

Step 9: Fill the Holes Slurry

After polishing half way through, process (around 400-grit) then fill the visible holes with Slurry (cement paste, color along with water).
Restart polishing once the slurry has dried for at least a day.
Check out through the How-To Slurry Guide for more details.

  1. Final Polish

Clean the slurry off by polishing the piece with the high-grit pads (400-grit and higher).
The last step is to finish the piece by sealing it. This will keep it looking neat and will preserve the polished look.