Concrete floor grinding and shot blasting
Every resin floor and coating bonds to the surface it is laid on and bare or old concrete is rarely ready to bond to. It carries a weak, dusty layer, old coatings, sealers, paint and contamination and anything laid straight over that is really only stuck to the dust. Mechanically grinding or shot blasting the surface strips all of that away and opens up a clean, sound profile for the new floor to grip, which is why it is the first step on almost every job.
Surface Specialists arranges floor grinding, shot blasting and mechanical surface preparation as part of getting a floor ready to coat. We match your project to the right method for the slab size and condition and arrange the work by experienced specialist contractors using dust-controlled equipment. From survey onwards you deal with one specialist contractor. This page explains what sanding and grinding involve, the methods used and how the right one is chosen.
What is sanding and grinding?
Sanding and grinding is the mechanical preparation of a concrete floor, removing the weak surface layer, old coatings and contamination and leaving a clean, slightly roughened profile for a new surface to key into. Floor grinding on concrete almost always means diamond grinding: rotating diamond-tipped heads that grind back the surface to sound concrete and flatten minor high spots in the same pass.
It is the groundwork that makes a resin floor, coating or screed bond and last. On a small or detailed floor the surface is ground; on a large industrial slab it is often shot blasted instead, which does the same job faster over a big area. Either way the aim is the same: a sound, clean, keyed surface rather than a smooth, dusty, contaminated one.
Why does mechanical preparation matter?
Bare concrete carries a thin, weak layer called laitance, along with dust, curing residues and often old paint, sealer or adhesive. A coating laid over that bonds to the weak layer, not the solid concrete underneath, so it lifts, peels or flakes early no matter how good the system is. Mechanical preparation removes the weak layer and gives the resin a clean, textured surface to grip.
It is one of the biggest factors in how long a floor lasts and the easiest to skip, which is why poor preparation is such a common cause of failure. Grinding or blasting a floor properly is unglamorous, but it is what turns a slab into a base a coating can actually hold onto for years rather than months.
Preparation methods
The right method depends on the size and condition of the floor and the system going on top, confirmed at survey.
Diamond grinding
Rotating diamond-tipped heads grind back the surface, taking off laitance, old paint, sealers and adhesives and flattening minor high spots. It is the standard preparation for most resin floors and leaves a clean, even surface ready to coat and it works well on smaller, detailed or enclosed floors.
Shot blasting
Shot blasting fires fine steel shot at the floor to clean and texture it as it passes, recovering the shot as it goes. Heavy contamination or a stubborn coating can need more than one pass. It prepares large areas quickly and consistently, which makes it the usual choice for warehouse and industrial floors where there is a lot of ground to cover.
Scarifying
Where a thick coating or a heavy build-up has to come off, or a deeper texture is needed, scarifying cuts more aggressively into the surface than grinding. It is used for tougher removal jobs before the floor is ground back smooth.
Floor sanding
For lighter work and finer finishing, the surface can be sanded back to clean and smooth it ready for the next stage, often as part of preparing or refining a ground floor.
Grinding or shot blasting: which is right?
Both clean and profile a concrete surface and the choice comes down to the floor. Diamond grinding suits smaller, detailed or enclosed areas, lifts old coatings cleanly and flattens high spots and it can work right up to edges and into corners. Shot blasting suits large, open slabs, covering ground quickly and leaving a consistent profile, which is why it is so often used on warehouse and factory floors.
In practice many projects use both: shot blasting for the main floor area and grinding for the edges, corners and detail. We confirm the method at survey based on the size of the floor, its condition and the coating it is being prepared for, so the surface is right for what goes on it.
Removing old floor coatings and paint
Mechanical preparation is also how an old floor finish is taken off. Failed resin, worn floor paint, sealers and adhesives are ground or blasted away rather than coated over, because a new system bonds to sound concrete, not to the old coating it is trying to replace. Removing floor paint and old coatings is a routine part of preparing a floor that has been finished before.
Trying to skip this and coat straight over an old surface is one of the most common reasons a new floor fails. A sound, well-bonded coating can sometimes be overcoated once it has been tested and abraded, but where the old finish is failing or the system is not compatible it is removed and the surface brought back to a sound, clean base before anything new goes down.
What to know before you prepare a floor
Dust is controlled. Grinding and blasting are carried out with dust-extracted equipment, so the work is dust-controlled rather than dust-free. Whether that suits an occupied or sensitive site depends on how the working area is isolated and on noise and access, which the contractor assesses at survey.
It is the first step, not the whole job. Once the surface is prepared, the floor may still need levelling, damp-proofing or repair before coating. See our floor screeding, epoxy DPM and concrete repairs services.
The profile is matched to the coating. Different systems need different surface profiles to bond correctly, so the preparation is specified for the floor that is going on rather than done to a single standard.
Why choose Surface Specialists?
Mechanical preparation is the foundation of a floor that lasts and the result comes down to the right method carried out properly by people who do this work every day. That is what we arrange, matching the project to a specialist contractor who looks after it from start to finish.
- A specialist focus. We concentrate on resin and surface treatment, so the preparation is matched to the slab and the system going on rather than a one-size-fits-all answer.
- Experienced contractors. Grinding and blasting are carried out by established specialist contractors with the right dust-controlled equipment for the job.
- Right profile, first time. The surface is prepared to suit the coating, which gives the floor the best chance of bonding and lasting.
- One point of contact. From survey through to a prepared floor, you deal with one specialist contractor.
Sanding and grinding is one of our subfloor preparation services, alongside floor screeding and epoxy DPM. It underpins our industrial and commercial resin flooring. Learn more about Surface Specialists or explore the full range of resin flooring we cover.
Areas we cover
We arrange floor grinding and shot blasting through experienced specialist contractors and are steadily extending the areas we cover. See our areas we cover hub for local detail, including resin flooring in Manchester with more local pages being added.
Get a quote
Tell us about your floor and what is going on it and we will arrange a free site survey and the contractor provides a written specification and quotation, typically within 48 hours. There is no obligation. Contact us to get started.
GET A FREE SITE SURVEY & QUOTATION
Frequently asked questions
What is floor grinding?
Floor grinding, or diamond grinding, uses rotating diamond-tipped heads to grind back a concrete surface, removing the weak top layer, old coatings and contamination and flattening minor high spots. It leaves a clean, slightly textured surface that a resin floor or coating can bond to properly.
What is the difference between grinding and shot blasting?
Both clean and profile concrete. Diamond grinding suits smaller, detailed or enclosed floors, lifts old coatings and works into edges and corners. Shot blasting fires steel shot to prepare large open areas quickly and consistently, which suits warehouse and industrial floors. Many projects use both, grinding the edges and blasting the main area.
Can you remove old paint and coatings from a concrete floor?
Yes. Worn floor paint, failed resin, sealers and adhesives are ground or blasted off as part of preparation, because a new system has to bond to sound concrete rather than to the old finish. Removing the old coating is a routine part of preparing a previously finished floor.
Is grinding a concrete floor dusty?
Far less than it used to be. The work is carried out with dust-extracted equipment that captures the dust at source, so it is suitable for occupied and sensitive sites as well as empty buildings. It is a much cleaner process than older grinding methods.
What happens after the floor is ground or blasted?
Once the surface is prepared, the floor is checked and any further steps carried out: levelling with a screed, applying an epoxy damp-proof membrane where moisture is high, or repairing damaged concrete. The prepared surface is then primed ready for the resin system to go on.
Which areas do you cover?
We work through a network of experienced specialist contractors and are extending the areas we cover. Contact us to confirm cover for your project.