How to Polish Concrete

Concrete floors are commonplace in a whole host of environments. 

From commercial organisations to industrial settings, you’ll likely come across concrete floors on a regular basis without even realising it.

For example, every time you walk across a shopping mall or travel to an airport, you’ll almost certainly be walking on a concrete floor. 

Typically, concrete floors should be polished at least 28 days after pouring has taken place to make sure it has properly cured. 

Polishing a concrete floor can bring a wide range of benefits including strengthening the surface, improving its appearance and making it more durable. No matter what the reason you’re polishing the floor for, it is a fairly straightforward process if you know how to do it.

In this article, the team here at Concrete Supply UK will take a closer look at how to polish concrete, outlining everything you need to know about the process.

Read on to find out more… 

How to polish concrete 

If you’ve not polished concrete before, it’s important to recognise that it takes a bit more skill than a simple DIY project. Heavy equipment and specialist tools are always required so you must always follow the correct health and safety protocols to ensure the job is done properly and safely. 

We’d recommend calling a professional to help if you need support when polishing concrete. 

While the use of heavy machinery can be challenging if you know how to operate it the steps are actually quite straightforward. 

This includes the following:

Prepare the surface 

Before you begin, you must ensure the surface you are working with has been properly prepared. 

You will need to clean and patch the surface, and this can be done by properly scrubbing the area thoroughly with a bristle brush and warm water. You can also add some mild detergent for particularly stubborn stains. If you decide to use a chemical cleaner then you should also make sure you are wearing safety goggles or a face mask. 

By cleaning the surface first, you can identify any cracks or damage that will need to be repaired. This should be done with concrete filler or a patch material. The floor must be smooth and consistent before any polishing takes place.

Test the hardness 

Next, you must check the hardness of the surface before starting to polish the floor.

Determining the hardness level will help you to decide what kind of grinding discs for the later steps. 

To test the hardness, you will need to use a Measurement of Hardness Scale (MOHS). If you don’t have one, you can purchase these online. 

Using the MOHS’ picks, hold it like a pencil and apply some pressure to the floor. Apply the same level of pressure as if you were writing and scratch the surface by creating a small line. Keep trying different numbered picks until you discover one that does not leave a line. 

Begin with the highest number and work your way down. 

If pick number 7 leaves a scratch but number 6 doesn’t, the concrete will have a MOHS hardness of 6.5. 

Concrete hardness is defined as:

• Soft – 5.5
• Medium – 6.5
• Hard – 7.5 or higher 

The relevant hardness will determine what grinding discs you will need. 

Use a grinder 

Once you have determined the concrete’s hardness, rent or buy a concrete grinder with the relevant discs. 

Before you use it, make sure you have safely prepared. Wear a dust mask, safety goggles, thick gloves, non-slip footwear, safety helmet and earplugs. The grinder will be very loud and create a lot of dust so it’s important you are protected.

Always follow the grinder’s instructions. Turn on the device and turn the disc in a half-circle motion, slowly moving it forward over the entire surface. 

We’d recommend starting from a corner wall and working your way over to the opposite corner, repeating the process as you go. Pass over the whole surface using different type of discuss (40-grit, 80-grit, 150-grit, 200-grit and 400-grit) to ensure the job has been completed properly. 

Vacuum the dust

After you have completed the grinding, make sure you spend some time vacuuming all of the dust and debris with a wet-dry vac. 

This will make sure the area is clean before the next step. 

Buff the surface 

Next, you should buff the surface. 

Attach a burnishing pad to the grinding disc that was previously on the grinder. Go over the surface using the same half-circle motion we mentioned earlier and using the corner-to-corner method. 

You can rent a burnishing pad online.

Apply a concrete sealer 

Now, it’s time to seal the concrete. 

Apply a thin layer of either a water-based or solvent-based concrete sealer to the floor. A roller or sprayer will help protect the concrete from grease, dirt, and other types of stains.

Wait two to four hours, and then apply a second layer of the sealer. You should always make sure the air temperature is above 10°C during the process and for 24 hours after.

Once your sealer is fully dried, you should buff the concrete one final time. You will then be left with glossy and smoothed concrete floors and you should wait 24 to 72 hours before walking on the surface.

Benefits of polishing concrete 

Polishing concrete offers numerous benefits, making it a highly desirable flooring solution for all kinds of settings. As mentioned above, the process involves grinding down the surface to create a high gloss finish that provides durability and aesthetic appeal. 

Some of the great benefits you can receive from polishing concrete include:

• Durability and longevity: Polished concrete floors are extremely durable and can withstand heavy foot traffic and equipment. This makes them ideal for industrial and commercial settings such as warehouses, factories and retail spaces. The polishing process involves strengthening the surface, preventing chipping, cracking and other types of damage. Unlike more traditional flooring options that might need to be replaced every few years, polished concrete can last for decades with minimal maintenance required. 

• Low maintenance: This leads us nicely to the low maintenance that polished concrete offers. This is one of the most appealing aspects of polished concrete. Due to the fact that the surface is made to be resistant to dirt and staining, there is no need for frequent cleaning or waxing. Instead, only occasional sweeping and mopping with a damp mop will be required to keep the floor looking pristine. Not only does this save time, but it also reduces the associated costs related to cleaning and ongoing maintenance. 

• Enhanced aesthetics: Polished concrete offers a sleek and modern appearance that can complement a variety of interior design styles. The surface can be customised with different levels of gloss – from a subtle satin finish to a high-gloss, mirror-like reflection. Additionally, dyes and stains can be added to create a wide range of colours and designs, allowing for further personalisation. This versatility makes it a popular choice for both contemporary homes and stylish commercial spaces. 

• Cost-effectiveness: Polishing concrete is a cost-effective flooring option, particularly when compared to other materials like hardwood, tiles or carpet. The initial investment is relatively low and since polished concrete doesn’t require periodic coatings or replacement, the long-term costs are even lower. Furthermore, many buildings already have concrete subfloors so polishing them eliminates the need for buying more flooring materials. 

• Energy efficiency: Polished concrete floors can also contribute to energy savings in buildings. The glossy finish reflects light, improving ambient lighting in a space and reducing the need for artificial light during the day. This can help lower the energy consumption and associated costs. Additionally, concrete has excellent thermal mass properties which means it can absorb, store and slowly release heat. This is a great way to maintain a consistent indoor temperature, reducing the need for heating and cooling. 

• Eco-friendly: Concrete polishing is also an environmentally friendly option which utilises the existing concrete slab, thus eliminating the need for additional materials. Furthermore, polished concrete doesn’t require the use of harsh chemicals for maintenance or sealing unlike other flooring types such as carpets and wood that might use adhesive coatings. The process also reduces waste, as it prevents the need to dispose of old materials or install new ones. 

• Improved air quality: A somewhat unique benefit of polished concrete is that it is hypoallergenic. This means it doesn’t harbour dust, allergens or mould. This is in direct contrast to carpet which traps dust and other particles. Instead, polished concrete has a smooth surface that is easy to clean making it a great option for people with allergies or respiratory issues. 

Here at Concrete Supply UK, we provide a wide range of concrete types to customers nationwide. Whether you’re a domestic customer who just needs that perfect mix for a DIY project or work for a large-scale construction company that needs regular, commercial concrete deliveries, we can cater our offering directly to your needs. In a recent survey more than 96% of our construction clients said they were highly likely to recommend us, so why not contact us today to progress your project?