"By failing to prepare, you are preparing to fail." Benjamin Franklin’s famous quote applies even to flooring.It’s absolutely essential your floors are prepared correctly before laying a floor covering, applying a coating, and starting the concrete polishing process.    

Have you ever had a floor coating fail, a call back to fix an epoxy floor job, remove a sealer that's been applied or had to fix a floor that wasn't prepared? Once you've seen this before you NEVER want to see it again, which is why we've been asked by a number of Coating manufacturers to put together this quick guide on different types of concrete preparation machines and their applications and finishes they will leave.

The International Concrete Repair Institute has developed a set of guidelines for assessing a concrete surface profile (CSP) ranging from CSP1 (smooth) to a CSP9 (very rough).

This guide is pictured below.

As you know some projects need a lot more floor prep work than others. It could be anything from lifting off an old floor covering that had a really thick adhesive, grinding down rubber based glue that threatens to react with heat and smudge with friction when grinding, removing high spots or imperfections from a concrete that is over 30MPA, preparing the concrete for polishing, chasing out old cracks or joints to repair. and joint sealing, or testing the slab for moisture before laying.

Each is just as important as the other, no matter how much (or little) work it needs, floor preparation is essential for making sure the jobs done right the first time every time.. Using different types of preparation machines will always give you a different CSP for example a single head machine is typically going to give you one type of CSP whereas a planetary machine will give you a smoother CSP rating, depending on the grit and bond of diamond grinding shoes that you use.  

Typically a scarifier or scabbler will be the harshest on the substrate and leave you with a very textured concrete surface. Here’s a short guide to show the typical CSP achieved on the common machines used for floor preparation. What do you want to achieve in concrete floor preparation?

• Removing existing coatings or laitances?
• Grinding to achieve a level floor, free from high spots and imperfections from the pouring and placement of the concrete.
• Grinding off any old glues or tough rubbery adhesives that react and smears across the floor when heated.
• Ensuring the surface is sound and in a good condition to lay, coat, or apply product on. In some cases, you may need to harden the slab.
• Decontaminate the concrete surface by removing any oil, grease, fatty acids, or stains. This is a common issue in the food industry, when preparing a floor with acid it is not neutralised and means the coating will often fail. The most common way of floor preparation for this is grinding.
• Grinding off soft, flaky or rain damaged concrete or alternatively a really hard floor (40MPA +).
• Repairing cracks, joints, sloping or removing trip hazards in a floor?

By preparing your floors right you will have the confidence to be able to ensure you won’t be back to do any repairs or maintenance. It's that simple.

Concrete Grinding is among the most popular forms of concrete floor preparation. It uses diamond segments on a rotating disc to grind, level, smooth, clean, or texture the top surface of a concrete slab. Most concrete grinders run with a Knock-on Diamond shoe system, allowing you to vary and change the grit, bond, and matrix of the diamond according to the finish you want with ease. Specialty diamonds, including the PCD diamonds (polycrystalline diamonds, they work by tearing off any coating. If you can imagine running 2 fingers through the sand this is essentially how a PCD will work on any coatings), remove heavy glue, paint, adhesive, or coatings much quicker than a traditional diamond.

Removing thinner products thinner than 2-3 mm is often done with a more aggressive diamond (16 – 20 grit). Diamond grit run a lot like sandpaper grit. The lower the number the more coarse the diamond will be. The higher the grit, the smoother the surface your grinder will leave. At around a 40/60 grit and higher depending on the matrix (The metal that holds the diamonds in) of your diamond, the grinder will start eliminating swirl or texture marks.

Scabblers use compressed air to hammer piston-mounted pieces that vibrate in and out to remove product from a concrete surface. These units leave a rough textured surface and often remove up to 6mm of concrete in a single pass.

Scarifiers are designed to give a fast, high-speed removal of concrete and coatings using Tungsten or hardened steel flails to strike the surface over and over. This can leave a clean, roughened, or textured surface depending on the types of flails (Several different ones available depending on what is being removed)  used. Also known as a planner, milling machine, or rotary cutter, these units have multiple uses for traffic line removal, surface profiling or concrete surface preparation. They give an effective finish when used on a number of surfaces such as asphalt, bitumen, and concrete. With the ability to change the cutters from star, tungsten cutters, or milling flails, the finish they leave varies from project to project. 

Shot blasting is a single-step process that quickly removes, cleans, and textures a concrete surface in a single pass. It quickly removes laitance, paints, old coatings, dirt, and other surface products in or on concrete. This process prepares new concrete floors or steel decking for new coating application, and it improves the bonding strength of the product to the surface. Shot Blasting is a dust-free method of abrasion where hundreds/thousands of steel shot particles race out of the machine, propelled by the motor to remove the top layer before bouncing back into the shot blasting system to be used again. The steel shot (garnut) profiles the surface.    

Acid etching is one of the methods of concrete surface preparation not so readily used as it is a very unsafe and would not be allowed on majority of sites. This is primarily used for lighter duty applications since the weakly bonded laitance product is not completely removed in this process. Acid etching does not remove surface contaminants, which must be removed before the acid etching process itself. Diluted acid is applied to the concrete floor and reacts with the concrete surface.

The resultant surface must be thoroughly high-pressure washed at 3000 PSI to etch the surface and remove the acid solution. Then Bicarbonate needs to be used to neutralise the acid. If this is not done there is a much greater chance of having a coating fail. It then needs to be vacuumed and allowed to dry properly for 48 hours.

This long process is necessary to ensure the acid is completely neutralized before applying the coating. It is not considered suitable to use on concrete that has any oil, grease, or curing agents. Needing to prepare your floor prior to laying, applying an epoxy coating, waterproofing membrane or adhesive and not sure what the surface finish is you need?

Call the Team at All Preparation Equipment on 1800 422 992 to ensure you get finish you need, the fastest way possible. Take a look online https://news.allprep.com.au/ where you can see the range of projects where these machines and equipment has been used to prepare floors.      

DISCLAIMER: The information in this post is for general use only. It should not be taken as a substitute for any specific advice given. Whilst every care is taken to ensure accurate information. All Preparation Equipment cannot accept responsibility for action taken as a consequence of this guide.