Proper surface prep is one of the most important parts of any concrete coating installation.
Before epoxy, polyaspartic, urethane, or another resinous flooring system can be installed, the concrete needs to be mechanically prepared. On many projects, that means diamond grinding the surface to remove contaminants, open the concrete, and create the surface profile required for the coating system and proper adhesion.
There isn’t one grinder that does everything.
Professional concrete coating crews use several different types of grinders on the same project. Large walk-behind grinders handle open floor areas, while smaller machines are used along walls, around columns, on stairs, inside closets, and anywhere else a larger grinder cannot reach.
Here are some of the grinders commonly used on professional concrete coating projects.
1. Hand Grinders
Best for: Edges, walls, corners, stairs, small spaces, and detail work.
A handheld concrete grinder is one of the most common tools in a coating installer’s surface preparation setup.
These are usually angle grinders fitted with a diamond cup wheel and a dust shroud. The diamond tooling mechanically abrades the concrete, while the shroud connects to a dust extraction system to help capture concrete dust as the grinder operates.
Hand grinders are particularly useful for preparing:
- Floor edges along walls
- Inside and outside corners
- Stairs and landings
- Around posts and columns
- Closets and small rooms
- Areas around drains and other obstacles
- Spots the main floor grinder cannot reach
- Cracks to open and clean before repair
On a typical floor preparation job, the large grinder can get relatively close to the perimeter, but it cannot prepare every inch of concrete. A hand grinder allows the installer to continue the mechanical profile right up to walls and other obstacles.
Why the Dust Shroud Matters
Grinding concrete creates a significant amount of very fine dust. A properly fitted dust shroud surrounds much of the grinding wheel and allows the grinder to be connected to an appropriate dust extractor.
This helps keep the work area cleaner while also improving dust control during the grinding process. This is important from both a cleanliness and health standpoint.
Using a Hand Grinder to Open Cracks
Hand grinders can also be fitted with a diamond crack-chasing blade to open cracks before repair. The blade follows the existing crack, removing weak concrete and creating a clean channel that can then be filled with the appropriate repair material. This process, known as crack chasing, is an important step in repairing concrete cracks with crack filler before the floor is ground and coated.
2. Corner and Edge Grinders
Best for: Tight spaces, doorways, stairs, and corners.
Sometimes a hand grinder is small enough to reach an area, but it may not be the most efficient tool for preparing it. This is where compact edge and corner grinders can be useful.
These smaller grinding machines are designed to mechanically prepare areas that are difficult or impossible to access with a conventional walk-behind floor grinder. Depending on the machine and tooling, they can be used around walls and door frames, on stair landings, in narrow areas, and in other awkward spaces.
Compared with doing the entire area using a handheld angle grinder, a dedicated compact grinder can give the installer better control and make it easier to achieve a more consistent surface profile.
These machines can be especially useful on residential and commercial projects with multiple rooms, doorways, steps, and architectural obstacles.
3. Walk-Behind Concrete Floor Grinders
Best for: Garages, commercial floors, warehouses, and larger open areas.
For the main floor area, contractors typically move to larger walk-behind concrete grinders.
These machines are the workhorses of mechanical concrete surface preparation. Instead of relying on a small diamond cup wheel, they use larger grinding heads fitted with multiple pieces of diamond tooling.
The additional machine weight, power, and grinding width allow contractors to prepare significantly more concrete with each pass.
Professional floor grinders are available in a wide range of sizes. Machines such as the Husqvarna PG 510, PG 6, and PG 8 are examples of grinders commonly used for different sizes and types of concrete preparation projects.
Mid-Size Floor Grinders
Mid-size grinders are commonly used for garages, smaller commercial floors, and projects where contractors need professional grinding performance without bringing in a very large machine.
Their smaller footprint can make them easier to transport, move through buildings, and operate in areas with tighter access.
They can be a practical choice for contractors handling residential garages, basements, retail spaces, and smaller commercial floors.
Large Planetary Floor Grinders
Larger planetary grinders are designed for higher-production surface preparation.
These machines are commonly used on larger commercial and industrial floors where contractors may need to prepare thousands or tens of thousands of square feet of concrete.
A planetary grinding system typically uses several grinding heads that rotate beneath the machine. This helps the grinder produce an even and consistent grind across a larger floor area.
The wider grinding path means more floor can be processed with each pass, while the additional weight and power help the diamond tooling work effectively against the concrete.
For large projects, using the right size grinder can make a major difference in production. Preparing a warehouse with equipment intended for small residential jobs would be extremely inefficient.
4. Remote-Controlled Concrete Grinders
Best for: Large commercial and industrial projects.
Some professional planetary grinders are available with remote-control operation.
Rather than physically walking behind the machine throughout the entire grinding process, the operator can control the grinder remotely.
This can reduce some of the physical demand involved in operating a large machine over long periods while allowing the operator to monitor the grinding pattern, tooling performance, and surrounding work area.
Remote-controlled grinders are particularly useful for contractors who regularly prepare large commercial and industrial floors.
Why Contractors Use More Than One Grinder
A professional concrete grinding setup is rarely limited to one machine.
A crew may use a large planetary grinder across the main floor, a smaller grinder in confined areas, and a handheld grinder around the final edges and corners.
The goal is to create consistent surface preparation throughout the area that will receive the coating.
If the centre of the floor is properly mechanically prepared but the perimeter is not, the coating still needs to bond to that less-prepared concrete. Areas around walls, corners, steps, posts, and doorways need to receive the same level of attention as the main floor.
Edge work and detail grinding are therefore an important part of the overall surface preparation process.
The Grinder Is Only Part of the Equation
Machine size is only one factor that determines how concrete is prepared.
The diamond tooling installed on the grinder is equally important.
Different diamond bonds, segment designs, and grit levels can be selected depending on the hardness of the concrete, the material being removed, and the surface profile the installer is trying to achieve.
A concrete grinder may be used to:
- Remove an existing coating
- Remove adhesive or other surface materials
- Remove surface contaminants
- Take down minor high spots
- Prepare bare concrete
- Expose aggregate
- Create a suitable surface profile for a new coating
The same grinding machine can perform differently depending on the diamond tooling installed underneath it.
Concrete Grinding and Dust Extraction
Concrete grinders are typically paired with dust extraction equipment.
Grinding creates a large amount of fine concrete dust, so professional grinders are commonly connected directly to dust extractors designed to collect airborne and surface dust as it is generated.
Larger grinders generally require more dust extraction capacity than a small hand grinder.
For that reason, the grinder and dust extractor are often treated as a complete surface preparation system rather than two unrelated pieces of equipment. A generator is also used to power the equipment.
Choosing the Right Concrete Grinder for the Job
As a concrete coatings installer, you’ll need several types of grinders to get your jobs done.
A handheld grinder may be perfect for working beside a door frame or grinding front steps but completely impractical for preparing a large garage floor. A large planetary grinder can quickly prepare an open commercial floor but may not be able to access stairs, corners, or narrow areas.
Professional concrete surface preparation is about matching the grinder, diamond tooling, and technique to the concrete and the area being prepared.
On many concrete coating projects, several different grinders will be used before the first coat of material is applied.
