Sanding Concrete

For a smaller surface area, use sandpaper with grit between 40-60, while for a larger surface, opt for a special diamond disc or a floor grinder to sand concrete efficiently. Utilize a grit ranging between 80-120 grit sandpaper to smoothen minor irregularities.

Which Sand Is Most Preferred for Concrete?

River sand, also known as natural sand, is a fine sand that is commonly found around streams and river banks. River sand's softness makes it suitable for use in concrete and brickwork. Plastering, RCC, and a variety of other block works benefit from river sand.

Why Should You Sand Concrete?

Concrete is the most commonly used material for construction and is well adapted for interior and exterior finishes. There are several reasons for sanding concrete, and we will look at the main ones below:

Finish

Sanding concrete is ideal for finishes. For homeowners, aesthetics are the main reason behind smoothing concrete. You might want polished concrete floors, kitchen countertops, or walls.

For instance, the salt and pepper finish needs some extra work. To achieve this finish, you need to remove 1/16th of an inch from the layer of concrete. The main goal is to remove concrete to leave a salt and pepper look resembling polished granite.

Round Edges

Concrete is hard and, in most cases, wear-resistant. After concrete curing, some imperfections such as sharp edges, spots, and protrusions might remain in the concrete. To minimize accidents or injuries, you need to sand the concrete to remove the bumps and imperfections. Sanding the protruding edges also enhances the surface’s overall appearance.

Remove Imperfections

Sometimes you might have hard-to-remove imperfections such as paint coatings and stains. Some stains are easy to remove, but others are resistant even to the most potent chemicals available. You can remove the affected layer of the concrete surface, which will restore the original appearance of the concrete.

Repairs

If there’s a crack in a concrete surface that needs repairs, you will need to sand the concrete surface to achieve a consistent look after the repairs. If you repair the concrete using sand fillers, and the color of the fill differs from the original concrete surface, you might want to apply paint after the sanding.

Sanding with Power Tools

The orbital sander is an ideal tool to use when sanding concrete. This will reduce your effort significantly and give a consistent polish to the counter or fixture. The one downside is how they are handheld with relatively small faces. If you are sanding an entire concrete floor, look for something larger.

For wide floor spaces, use a floor sander - also known as a drum sander or a concrete grinder. These can be operated standing up. These typically can attach to a vacuum for mid-project cleaning. Concrete grinders have diamond bits for the hardest possible sanding material. These are used both to remove any lingering paint or epoxy coating and then to polish the concrete.

Wet or Dry Polishing?

Wet has its advantages

Wet grinding and polishing also increase diamond life dramatically on medium-hard to very hard floors and allow for more aggressive grinding. Grinding wet can effectively remove a significant layer of concrete to expose aggregate. It allows the diamonds to cut faster on medium-hard and very hard floors.

Any contractor who has exposed aggregate knows it can take a long time to grind an entire slab down to larger aggregate. It takes time to take out high spots and expose aggregate as evenly as possible. Wet grinding creates more friction. And, more importantly, it keeps the diamond tooling cooler, which prevents metal-bond tooling from glazing over.

Using water in the first two or three steps of polishing helps remove scratches left behind by the metal-bond diamonds. Crews can finish out the floor using wet polishing in the higher grits for a duller, easier-to-maintain shine level.

Can concrete be sanded?

It sure can be done if you need to sand or smooth out a concrete surface! However, unless you have the right tools and skills, expect it to take some time. Wet or dry sandpaper will do the job, but don’t expect perfect results.

If you want a perfectly smooth finish, your best bet is to invest in one of the many concrete sanders available on the market. The sander types vary greatly, and most home improvement stores stock them, making them easy to get hold of.