How to get the best concrete coating for your garage or basement floors
Applying a beautiful finish to your garage or basement can improve the value of your home and give you years of enjoyment.
The concrete in your floors may have many unique conditions that need to be addressed to get the best results.
We have developed the following steps to help you in the all-important preparation process. While it may seem complicated, if you take your time and follow each step, you will avoid problems and end up with a great job!
We have broken the steps into two phases to avoid overloading you with technical detail.
- Testing for water and sealers
- Profiling and preparation
- Chemical profiling
- Patching holes and joints
- Application steps
We know from talking to hundreds of customers for our performance Epoxy-Coat garage Floor Coating Kits what kind of concerns they have in preparing the concrete surfaces.
Is your garage or basement suitable for epoxy coating?
Water Test: tape down a 16” BY 16” sheet of plastic and allow standing for 24 hours. If water collects between it and the floor there has moisture problem and any floor paint will probably fail.
Water Test: Pour water on the cement. It should soak into the cement in a reasonable time. If it beads up or just sits there for a long time, the concrete has been sealed or is contaminated with grease or oil. If so, it must be removed before continuing.
What Is profiling and why is it important?
The single most important aspect to creating a long lasting beautiful epoxy floor is to have a suitable surface for coating adhesion. To have a successful coating you must first profile or roughen the concrete so the epoxy has a sound base to adhere to. This can be done mechanically or chemically, depending on the condition of the concrete. The reason for profiling the concrete is to ensure that the concrete will accept the coating, and the coating will have something to “bite” onto. The most important aspect of floor coatings’ permanent adhesion is a proper cleaning and profiling of the surface.
Surface preparation is a significant portion of any epoxy coating project. Each surface and environment is different and unique. It is important to note that certain chemicals and materials added to the concrete before, during or after it is poured can cause a coating job to fail no matter what level of surface preparation is used. Suspects include special concrete curing compounds, chemical hardeners, bond/form release agents (bond breakers), and admixtures used to reduce/improve air entrainment, cement workability, gas forming, accelerated curing, etc. It is nearly impossible to know ahead of time how much preparation is necessary. A minimalist will simply brush or sweep the surface (perhaps degrease a spot or two), apply the coating and hope for the best. Often this is all a homeowner can do. Fortunately, they often get away with this alone.
Prior to profiling your concrete you should perform a sealer test. The sealer test is simple, and all it takes is some water. You will apply the water onto the garage floor and if the water beads in any areas, that is a sign that there is a sealer currently on the floor, or other contaminants preventing the water from penetrating the concrete.
Grease and oils can create serious adhesion problems for coatings. Degreasing and washing may appear to remove the grease or oil, but in badly saturated situations residual oils/greases seem to remain and may cause a coating failure in the future. While not definitive test, pouring a glass of water on the concrete and watching what happens can provide a valuable clue to coating adhesion. If the water quickly and evenly soaks into the concrete the surface preparation may be adequate at that point. Moisture either in the concrete, and/or migrating through the concrete can cause coating failure as well. Some epoxies will handle a wet or damp surface better than others. Note that crystals forming on the surface due to water migrating through the mineral rich cement can create forces of up to 1,500 pounds of pressure as they grow in size. Few coatings can withstand such “anti-bond” forces.
Sealer removal by Diamond Grinding
Sealers cannot be removed chemically, and will need to be removed mechanically. To remove the sealer mechanically, you will want to diamond grind the floor. Most local hardware stores rent out diamond grinders. Diamond grinding will not only remove the sealer, but will grind your concrete, creating a rough profile.
Chemical profiling with acid etching solutions
If the sealer test is performed, and the water penetrates into the concrete immediately, you can chemically prepare your concrete.
To chemically prepare your concrete you will want to use an acid etching solution. The most common acids used in the acid etching solutions are muriatic acid or phosphoric acid. Prior to acid etching, the user will want to use a mild degreaser diluted with hot water to remove any contaminants that may be on the concrete. Once the floor is degreased and contaminate free, the acid etching can begin.
Each acid etching solution may have different instructions, and it is important that in the instructions are read and fully understood before using the etching solution. Using a stiff bristled broom, scrub the premixed acid etching solution into the concrete, scrubbing in both directions.
Once the etching is finished, the premix must be rinsed from the concrete. Once the concrete has fully dried, check for any glossy or oily areas with water. If the water does not penetrate quickly, additional etching treatments will be necessary. The user will also want to check for any white film when wiping the dried concrete with fingers. If your fingers do not have a white film, your concrete floor is ready for coating.
In Phase II of our blog, we detail the steps for final profiling, patching holes and cracks and final epoxy application.