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Surface Preparation for Floor Coatings: DIY vs Professional

diamond grinder

“A house is only as strong as its foundation.”  It’s a quote we have all heard at one time or another. Its core idea is very appropriate to epoxy floor coatings.   Regardless of whether it’s a professional, like us, installing a commercial grade polymer or a homeowner installing a garage floor, epoxy paint kit, the success of either is entirely dependent on the foundation.  In this case, the foundation is the preparation of the concrete slab.

Whether the concrete is new or decades old, the longevity of any coating system begins with the preparation of the concrete surface prior to the application of the actual chemicals. Many methods exist to prepare concrete for a coating.   For the Do-It-Yourselfer, the typical method is acid etching or sanding.    For the professional floor coatings installer, mechanical diamond grinding or shot blasting is the norm.

DIY Methods – Acid Etching & Sanding

Acid etching is a common technique included in DIY kits, but it lacks the ability to properly prepare tightly troweled surfaces. It also cannot remove many of the substances that already have tarnished your concrete – such as existing paint, concrete sealers, or motor oil and other contaminants. All of these substances will decrease or alleviate the ability of the DIY coating to stick to the concrete.

Sanding is similar to the diamond grinding method, but floor sanders lack the ability to adequately open the pores and create a deep enough abrasion pattern.   Again, the coatings then cannot soak in or lock onto the “foundation” properly.

As a result, the homeowner will quickly notice “pox” marks or chips in their newly coated surface – many of which could have been prevented by properly preparing the concrete.

Professional Method – Planetary Diamond Grinding & Shot-Blasting

Conversely, the preparation of your concrete floor by a professional is going to be much more thorough. Professional coatings installers have the tools to get it done right, ensuring the coating actually adheres to the concrete.  In fact, the coating’s bond should be so strong to the concrete that if you pull hard enough on the coating, the concrete should break away!

A professional will use a mechanical preparation method, such as diamond grinding or abrasive blasting. This opens the top surface of the concrete floor – removing any substances or sealants – and makes the concrete porous again. This process allows the coating to properly adhere to the concrete – and not simply lay over the top of it.

As the beginning of our coatings process, we utilize planetary diamond grinders with HEPA filtered vacuums so that the dust and any contaminants are contained and don’t become airborne. Our prep work also includes filling in any cracks and fixing any areas that need addressed.  Only on rare occasion do we utilize our shot blaster, as that method is normally overkill for residential and commercial projects that are receiving a decorative coating.  

Granted, a homeowner or general contractor can rent grinders.   Nearly all rental grinders are single or dual-disc machines that utilize block-style diamonds.   These types of grinders are inferior to the more expensive, planetary grinders which feature 3 floating heads and industrial diamond sets.   Single and dual-disc grinders do not create a uniformly prepared surface as quickly or easily as a planetary grinder.   Our company has 7 of these planetary grinders for garage and commercial preparation, as well as two smaller units used for preparation of residential basements.

Building on the Foundation

Once proper surface preparation is complete, it’s time to move onto the installation of a high quality, commercial grade coating system.    In an upcoming blog, we are going to contrast the materials and maintenance involved in the DIY vs. Professional coating systems.