CONCRETE FLOOR SURFACE PREPARATION
1.) SAFETY FIRST! Read and follow all label instructions. Workmen should wear non-skid rubber soled boots, chemical resistant gloves, and safety glasses. Keep the area completely roped off the entire time required for preparation, application, and until the final coat has thoroughly dried and cured.
2.) If the floor surface is soiled or contaminated, clean with a Heavy-Duty, Industrial Strength Cleaner/Degreaser. Apply Cleaner/Degreaser, let sit for 15 minutes, then scrub with a stiff bristled broom to remove all dirt, oil, grease, etc. If floor is very heavily soiled, use Cleaner/Degreaser at a greater concentration, and repeat this step as many times as necessary, to be sure the surface is completely clean. Flush thoroughly with clean water. Remove all water with a squeegee or wet/dry vacuum.
3.) Mix one (1) gallon (3.785 L) of Commercial Grade 20% Hydrochloric Acid (Muriatic Acid) with up to one (1) gallon (3.785 L) of water in a plastic container to get a 10% to 15% concentration of Hydrochloric Acid. One (1) gallon (3.785 L) of this mixture will etch approximately 50 sq. ft. (4.65 sq. m.) of surface area. Apply and spread the solution evenly over the floor surface with a straw broom. Let the solution stand for approx. 3 to 5 minutes, or until all bubbling or fizzing ceases. Then immediately flush away the spent acid.
Never let acid dry on the surface.
After the initial acid etching step, check all areas of the surface for appropriate surface texture or profile (like very rough, 80-grit sandpaper) and proper porosity for coating adhesion by sprinkling water on the bare concrete surface. If the surface is properly etched so the concrete pores are open, the water will immediately be absorbed into the pores of the concrete without any beading of the water on the surface. If any water beading or runoff occurs anywhere, you must repeat Step 3 as many times as is necessary, to be sure the entire concrete surface is properly prepared. Failure to achieve the required concrete surface porosity and rough profile will result in unsatisfactory adhesion of any paint or coating to the concrete surface
4.) After the surface has been acid etched, it MUST be neutralized by applying 5% liquid chlorine (i.e. "Clorox" = 5% Sodium Hypochlorite). This step should kill contaminants in the concrete, such as food enzymes, bacteria, fungus, etc., which can inhibit proper coating adhesion if NOT completely decontaminated with chlorine. The surface should have a neutral (7 pH) before the application of any paint or coating.
5.) Flush thoroughly with clean water. Remove all water with a squeegee or wet/dry vacuum.
6.) Allow entire surface area to dry thoroughly; force dry if necessary with fans and/or heaters.
New concrete should be allowed to cure for a minimum of 28 days @ 75° F. (23.9° C.) and 50% Relative Humidity before the application of an acid solution or any paint or coating (however, SOMAY "HYCOTE" 151 Epoxy can be applied to properly prepared, uncured concrete).
Very dense, non-porous or chemically treated concrete that is not made rough and porous by the acid treatment or the presence of laitance (fine white particles) will require abrasive blasting (e.g. "Blastrac"), sandblasting, abrading or grinding, followed by vacuuming or thorough cleaning, to assure proper coating adhesion
If the surface has large cracks, gouges, etc., it should be patched with a Concrete Patching Compound, which is allowed to thoroughly cure prior to the application of any coating. A 100% Solids Epoxy Patching Compound can be used if a 2-component Epoxy or Urethane coating will be used. An acrylic resin modified concrete patching compound, can be used if a rubber, or acrylic latex coating will be used.
If applying an epoxy (except SOMAY "HYCOTE" 151), rubber, urethane or any other solvent-thinned paint or coating, the surface should be thoroughly dry. If applying an acrylic "latex" (waterborne) paint, the surface may be damp, but NOT wet.
Paint should be applied ONLY when (A) the ambient temperature, (B) the floor temperature, and (C) the paint or coating are all between 50° F. (10° C.) and 80° F. (26.7° C.) and the relative humidity is 75% or below. It is better to work in the shade (NOT full sun) so the surface being coated is not so hot that it acts like a hot pancake griddle, making the liquid coating solidify so fast it does not have an opportunity to penetrate the pores of the concrete surface to permit proper adhesion of the coating to the surface. If you are going to apply an acrylic latex (waterborne) paint, you can cool the surface by spraying with cool water just prior to application of the paint.
Do NOT allow the prepared surface to become contaminated between the preparation and application steps ... for example, be sure to wear clean, dry shoes when walking on the surface area to be coated, and keep it roped off.
When applying the paint, be sure to work the paint into the concrete surface, for example, by brushing the paint back and forth over the concrete surface, to get the paint to flow into the open pores of the concrete so you will get good adhesion of the paint to the concrete.
Equipment, Tools, Supplies Needed
Stiff Bristled Broom (to apply Degreaser); Straw Broom (to apply Hydrochloric (Muriatic) Acid)
Squeegee or Wet-Dry Vacuum (to help remove solutions & rinse water)
Large Fan (to help dry surfaces)
2 Plastic Containers - approx. 2-gal. (7.57 L) capacity (to mix water with Acid)
Garden Hose (to flush Degreaser and Acid) and Water Supply
Safety Equipment Needed
Rubber soled boots or shoes; chemical resistant gloves;
Safety glasses; Rope (to keep people off work areas)
Material Needed (Quantity for each 1,000 sq. ft. (92.9 sq. m.) of surface area)
Heavy Duty Degreaser
20% Hydrochloric Acid (Muriatic Acid) (For Step 3) - 10 gals. (37.85 L)
Chlorine Solution, such as 5% Sodium Hypochlorite (e.g. "Clorox) - 4 gals. (15.14L).