What is the Difference between Sealed and Polished Concrete?
Concrete is one of the world’s most common construction materials. It has high compressive strength and, if reinforced, it can also handle a considerable amount of tensile stress.
However, just like other man-made materials, concrete comes in many different forms. Because of the various concrete grinding and polishing methods, it can get confusing pretty quickly.
In this blog, we will take a look at sealed concrete and polished concrete. Although these two types have some similarities, they do have differences that need to be considered. Choosing the wrong type might cause significant problems to your business or place of residence in the long run.
To help you make the right choice between the two, we will look at the advantages of each one as well as the processes used to make them.
- How it’s made
True polished concrete floors are made by physically buffing the surface with grinders of different grits.
The first step is to ground the slab of concrete with a 30-grit grinder followed by a 70-grit grinder. This removes major blemishes on the base slab, allowing for a smooth finish at the end of the process.
Next, a grout is applied to fill in the holes that were made during the initial grinding process. The grout can be epoxy or a mixture of water, cement and sand. Once the grout has cured, a 200-grit grinder is used to remove the excess grout from the surface. This step also further polishes the concrete and removes blemishes made by the 70-grit grinder.
The next step is similar to this previous one, except the grout layer is much thinner and a 400-grit grinder is used to polished the surface. This ensures that the microporosities (microscopic holes on the surface) are filled in.
Afterwards, a densifier is applied to increase abrasion resistance and the density of the outer layers. The last step involves using a 700-grit and a 800-grit grinder to create a shine on the concrete surface.
If the polished concrete is going to be used for non-industrial purposes, it’s possible to go beyond 800-grit to give the floor a reflective, high-gloss finish.
One of the main advantages of polished concrete is it’s durability. It has high impact resistance, making it perfect for garages, warehouses and other areas that need to endure heavy traffic.
You can also customise the way your polished concrete looks. You can grind it beyond 800-grit to get a highly-reflective surface. Polished concrete features that timeless glossy look that you see in building lobbies, office spaces and shopping malls. Whether you’re using it for your place of business or your home, polished concrete will never go out of style. In addition, it is also very easy to clean and maintain.
You can also grind the concrete to a certain level so that your preferred aggregate exposure can be achieved. This means you can either have stone fragments on the surface or a clean finish.
The only downside of polished concrete is that it can be a bit pricey. Due to it’s complicated and involved process, it is considerably more expensive than its sealed counterpart. However, if you value durability and aesthetics, the price tag of polished concrete will be well worth it.
- How it’s made
As with polished concrete, the process begins with a 30-grit grinder. During this step, you can grind the slab to your desired aggregate exposure level.
Next, the concrete will be vacuumed and sandblasted. The goal of this step is to remove fine dust on the surface, preparing it for a layer of epoxy primer. The sandblasting/shot blasting process ensures that there is no contamination between the epoxy primer and the concrete slab.
Afterwards, a 25mm layer of epoxy primer is applied to fill in the holes on the concrete. The thickness of this layer is important as it prevents defects from appearing on the surface of the finished flooring. After an hour and half, an epoxy body coat is applied on top of the primer.
Before the body coat dries, a good amount of sand is scattered on the surface. Similar to the densifying process, this step will improve the sealed concrete’s abrasion resistance and surface density. After eight to ten hours, the excess sand will be vacuumed.
The last step is to apply the epoxy sealant, locking everything in place and making the surface wear-resistant.
Sealed concrete is perfect for those who want a quick but effective way of transforming their flooring. Though its surface has considerable impact resistance, it’s main feature is its resistance to wear. Sealed concrete is perfect for areas that see high foot and wheel traffic.
Sealed concrete is much cheaper compared to true polished concrete. It is an affordable way of adding durable flooring to your residential or commercial property.
Keep in mind that sealed concrete will need to be resealed every five years. So, although the upfront cost is less, the on-going maintenance might set you back a lot of money in the long run.
That was just a quick overview of sealed concrete and polished concrete. Both are great flooring options with each of their own pros and cons. The only thing you have to consider is your own personal requirements. Is cost a major factor to you? What about impact resistance and long-term maintenance? These are things you have to take into account when choosing between the two methods. If you get confused, you can always refer to the information above.