Can I sand down the concrete? This question is becoming more common as more property owners search for ways to enhance aesthetic appeal using concrete. Below, we explore the sanding options and how to go about them. Solid advice from one of the best demolition companies in Toronto and the GTA.
Reasons for Sanding Concrete
Many homeowners are finding concrete sanding investment-worthy due to its attraction and durability. It is the perfect solution for getting more finished floors and countertops, but only when done correctly.
Better Aesthetics
Concrete sanding gives dull surfaces a distinctive look that also lasts longer. With sanding, you can make your property stand out through perfectly finished floors, whether you want to add a sealant or a different type of finish.
Smooth Rough Edges
Concrete tends to chip with time, leaving sharp corners or edges that can be hazardous. Concrete surfaces can also have protrusions or spots after curing, but you can sand them down for safer results.
Consistency During Repairs
After repairing a small section of concrete, sanding is necessary to make the repaired section blend with other areas. Apart from achieving the desired consistency, sanding also enables staining to achieve an even look.
Eliminate Flaws
Sanding concrete makes room for improvements that boost the property value. For instance, the process allows the rectification of patches, stain removal, and smoothening of rough areas. Sanding is also critical if the surface requires coating. It is the only way to ensure the concrete surface treatment works if you want to fix imperfections.
Concrete Finishes to Consider
How to sand concrete floors is a discussion that is gaining popularity in the construction industry, although the reasons for sanding vary from person to person. Multiple finish options are available, making it easier to find a preferred style.
Some designs you may consider include:
Salt and Pepper
The salt and pepper finish consists of aggregates that remain exposed and form a pattern that looks like salt and pepper. The style requires a significant amount of sanding to uncover the speckled style. The salt and pepper design is common in industrial properties or larger institutions like malls, but it can work with any architectural design.
The finish does not leave a coarse surface – the texture usually has a subtle but decorative roughness.
Exposed Aggregate
Exposed aggregate looks like salt and pepper, but it requires more sanding to reveal the components in the concrete without leaving too much air space. The job calls for sanding approximately ¼ inch of concrete, so more advanced sanding tools are required to handle such aggressive sanding. Most people use powered polishers or sanders.
The distribution of the aggregates in the concrete is critical, but the types range from granite to glass. Property owners choose the stones to expose according to their visual appeal. The rough texture is applicable in outdoor spaces like patios or driveways.
Stained Concrete
Polished concrete does not have to be plain. You can stain it with your preferred colours to make it outstanding. The process involves sanding the surface, then adding a select colour and sealant on top.
Polished Concrete
Polished concrete is the most popular option, thanks to its glossy nature. Most people prefer to leave surfaces shiny because of the evenness and minimal sanding effort required. High-grit sandpaper is more effective in removing all imperfections and leaving the floors and countertops polished.
Epoxy
Epoxy requires a porous surface to bind to; therefore, the concrete will not require too much sanding. Minimal scuff sanding is enough to get the job done, but you must remove all coating, whether paint or sealant. Remove all previous finishes for the epoxy to adhere correctly.
What is the Best Tool to Sand Concrete with?
Concrete sanding is labour-intensive, but the correct concrete sander can simplify the job. The equipment you choose should depend on the scope of work and the concrete type. That is why you should compare various equipment by their pros and cons.
Belt Sander
Belt sanders are powerful equipment suitable for projects that require more aggressive sanding. They are also ideal for more substantial projects because they can remove large amounts of concrete when set at high speed.
Belt sanders are available in two options – handheld and stationary sanders. Both options are easy to use, thanks to the embedded vacuum systems that clear the dust as you work. Although the sanders can reduce the workload on challenging projects, they also leave undesirable marks. You can mitigate that by using sandpapers to smooth the surfaces. You can also start with a belt sander and finish with a gentler device to achieve perfection.
Orbital Sander
An orbital sander is a handheld device that sands in random but circular motions, meaning you can use it in any direction. Its performance routine makes it suitable for various surfaces, including bathroom floors and countertops.
Sanding concrete floors with an orbital sander reduces the effort required for the job and allows faster completion. It has a small sandpaper that you can use on small surfaces, especially if you want to enhance the finishing by polishing the surface. On the downside, the sander produces a lot of sand because of its dust collection system.
Handheld Sander
A handheld concrete sander is an easy-to-use gadget, perfect for sanding walls and countertops. Concrete sanders are also known as edge grinders because of their size. They have varying speed options to choose from depending on the task. They also have in-built water supply alternatives and are best for corners because they are easy to maneuver.
Controlling handheld sanders is easy, but using them vertically can be a challenge. The devices also create a lot of concrete dust that can be dangerous when inhaled. However, a hose and vacuum attachment on the equipment can solve that problem.
Angle Grinder
This sanding equipment has discs, side handles, circular grinding blades, and a motor system that enables its functionality. That is what differentiates it from conventional sanders that use sandpapers. Although angle grinders are fast, they can produce uneven surfaces. Therefore, utmost care is necessary for the best outcome.
Floor Grinder
Floor grinders are large and suitable for large surfaces. The electric machines have rotating pads that smooth the concrete floor as you push the sander. That means you can walk on the floor without worrying about slipping. The concrete grinders also have adjustable handles that allow switching between polishing and sanding and are more suitable for outdoor spaces like patios.
Various types of concrete grinders are available. Examples include edge grinders, corner grinders, roller track grinders, and oscillating machines.
Polishing Pads
Polishing pads are handy when electric tools are unavailable or if you only need to sand a small section. They function the same way as sanders but take more time and effort because of manual labour.
Choosing polishing pads with the correct grit is critical in improving efficiency during the job, considering the type of concrete and finishing you intend to achieve. Compatibility with wet surfaces also matters because you need to mitigate dust when using the polishing pads.
Some projects may require several polishing pads, starting with coarser polishing pads and finishing with finer ones for a smoother surface.
How to Sand Concrete – The Steps
Sanding concrete floors involves several steps that you should follow correctly for the perfect finish. Start by selecting a suitable style from the many options available. Determine whether you want a bit of texture or a smooth surface, then choose an appropriate concrete sander. The size of the floor or countertop that requires sanding also matters – some tools are suitable for smaller jobs and others for substantial tasks.
1. Surface Preparation
Start by preparing the surface to be sanded for the best overall outcome. Preparation involves removing grime, dust, and other debris. Filing the cracks and chiselling bumps also fall under preparation. The crack filler should be the same colour as the concrete, and the area should be smooth.
Use a trowel, pressing it firmly to prevent the formation of air pockets. Allow enough time for curing and sand any bumps from the filling. When cleaning, use soap and water and rinse properly. Leave the surface to dry completely before moving to the next step.
2. Pick a Sanding Type and Wear Protective Gear
Since sanding concrete floors can be dangerous, you need protective gear like goggles and a mask to shield your lungs and eyes. Failure to protect yourself can result in respiratory issues or other health complications. Cover furniture as well before sanding.
Do you sand concrete wet or dry?
Concrete sanding can be wet or dry. Wet sanding involves the use of water when the equipment touches the concrete surface, while dry sanding only involves the use of water immediately after sanding. Both options have pros and cons worth considering. For instance, dry sanding uses less power, but wet sanding controls the volume of dust produced.
1. Begin Sanding
Subdivide a large area to simplify the job. That will also ensure a consistent finish on the entire surface. Sanding should begin with a coarse sander or a 30 – 60 grit pad. Start from the corners and move toward the center. Keep the sander levelled and use a handheld sanding pad where electric devices cannot reach. A dry sander in the first round can remove imperfections easily. Apply light pressure in a circular motion, keeping the strokes long and even.
Remove all debris after the first sanding round. Clean the surface using water and a soft cloth after vacuuming all the dust. Cleaning between the rounds of sanding keeps the area fresh, reducing the risk of too much grinding.
If you are wondering what sandpaper to use for sanding concrete, it all depends on the texture you want to achieve on the floors. You can use sanders with finer grits during the second and subsequent rounds until you get the desired finish. Follow that procedure while working in small sections and cleaning as you go. Smoother finishes require 200 – 400 grits, while medium textures are attainable with 80 – 100 grits.
You can sand the concrete as many times as you wish – there are no limits to how many times you can do it. The texture you want is the determining factor. Ensure you rinse the surface after the final sanding and leave the surface to dry before finishing.
2. Add Sealant
Protecting the surface is as crucial as sanding correctly; that is why you need a sealant. Sealing the newly sanded surfaces keeps them looking great for extended periods. You can use a paintbrush on the corners and edges, giving the coating around two days to dry completely. Improve ventilation in the room by opening windows.
Additional Tips
Sand in the right direction – the same direction as the previous stroke. Go with the grain of concrete instead of against it.
How to sand down concrete to level – A long level can show the evenness of the surface in larger areas, but you can manually check the space between the sander and concrete surface on smaller sections.
Maintaining Sanded Concrete
Maintenance prolongs the stellar condition of sanded concrete surfaces after all the hard work you invest in transforming them.
- Use a clean mop and water when cleaning the surfaces. Wipe off spills quickly to avoid leaving stains.
- Apply floor wax in areas with high foot traffic and use protective caps on furniture legs. These measures prevent scratches on the floors.
- Use neutral floor cleaners that will not corrode the surfaces or cause them to wear off prematurely.
- Avoid using mats with rubber lining on finished concrete floors. Anything that can trap moisture from the concrete can cause the deposition of hard minerals. Potted plants can cause the same issues unless you use raisers to lift them.
Can Concrete Be Sanded Down?
Concrete sanding can be a DIY project or be done by a professional. If you choose to DIY, read the instructions about preparing concrete before sanding. If you hire an expert, you can avoid the mess, challenges, and imperfections associated with the job.
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