Concrete Floor Acid Stain Application

Posted by DSH on Thursday, July 27, 2006

A. Preparation of Existing Concrete Surface
Curing agents, sealers, paints, coatings, waxes or water repellants must be removed prior to the concrete acid stain application. Mechanical methods of removal are not advised as they may scratch the surface leaving unsightly patterns of scratches in the surface.
Older concrete surfaces need to be tested for acceptance of the acid stain. The cleaned surface must be penetrable by water. If water beads on the surface and is not readily absorbed into the concrete, mild acidic detergents such as a concrete renovator may be of assistance in your concrete acid stain application. Never acid etch concrete to be acid stained. This will use up the free lime in the concrete and leave you with a surface that is not stainable for concrete floor acid stain application.

B. New Concrete:
Freshly poured concrete should be sufficiently cured, a minimum of thirty days before the concrete floor acid stain application. If score patterns are desired, a diamond blade grinder may be used to score various patterns, borders or designs onto the surface prior to, or after concrete acid stain application. If light colored grout lines are desired score after staining process is complete.
Freshly poured or recently poured concrete needs to be scrubbed thoroughly, sometimes more thoroughly than old concrete due to what is known as latency, this is the "dust", if you will that remains on top of the concrete after it is poured and cured.
This latency will not allow the concrete floor acid stain to penetrate as is needed to provide a beautiful concrete acid stain application so we need to use a floor maintainer (buffer) with a black or green scrub pad and TSP (trisodium phosphate) or our favorite, Dyna Blue, to scrub and shop vac the floor clean.

C. Cleaning of Concrete:
These next two steps will take you from having a good concrete stained floor to a Fantastic concrete acid stain application. As we say in the Decorative Concrete industry, application of the pretty stuff is easy but the preparation of the concrete is what makes the difference and boy will this make a difference as you'll see and be very happy you took the time and effort to do it.
First we need to scrape the paint and other things off the concrete before the concrete floor acid stain process, you will not find them all but when you wet the concrete you will see everything as we see here, we have scrubbed the concrete and are now vacuuming.

D. Citrus-Degreaser
This is a very important step and most manufacturers and even many "acid stain professionals" don't take this next step in the concrete floor acid stain process, which is critical to a beautiful concrete floor acid stain application for your floor. If the floor has some oil or grease or really anything questionable on it we recommend that you clean the floor with Citrus Degreaser. Dilute with 8 parts water and scrub the floor with a black pad and a buffer. Rinse and use a shop-vac to remove residue, if possible always use a shop vac as this will pull the residue and dirt out of the pores of the concrete.
This step is only necessary if your concrete is extremely dirty. If your concrete is normal or just slightly dirty the following process is all that is normally needed.

E. Concrete Renovator
Next dilute Dyna-Blue, 2 parts water to 1 part Dyna Blue. Moisten the concrete and use a garden sprayer with all plastic inserts to spray the dilution over the entire floor and scrub lightly. Make sure to have proper ventilation. Let the mixture stand for approximately 5 minutes or until all fizzing and bubbles have ceased.
Use a buffer with a black pad and scrub the floor thoroughly. Flood the floor with water and shop vac the floor to achieve the cleanest floor possible for concrete floor acid stain application.

F. Coverage
Make sure that your concrete is completely dry. This sounds like an obvious statement but you would be very surprised to know how many folks take this for granted. When we say dry we mean that it is better to leave the floor overnight to dry unless it is summer and the AC is on and a few fans are turned on. The reason for this precaution is that is if the concrete is wet or even slightly damp this will dilute the concrete floor acid stain and probably require you to spray again, therefore this is essential in the concrete acid stain application process.
One coat of Acid Stain is all that is usually needed. You may feel that you want to go back over the area and spray a little more in some areas. Acid Stain can be applied at a rate of 1 part water to 1 part stain. The coverage rate will be 135-200 square feet per gallon. When applicable after you have tested the stains in an inconspicuous area, you may choose to dilute the stains more to achieve a slightly lighter color. .

G. Concrete Stain Application
For an excellent concrete floor acid stain application all surfaces must be completely dry, prepared and tested as described above. Acid Stain should be shaken well and poured directly into a plastic sprayer with a plastic filter and internal acid resistant plastic parts. The sprayer should be continuously pumped to keep a constant pressure while applying concrete floor acid stain. We are very partial to a battery operated backback sprayer sold by Crusader Manufacturing which will spray 120 gallons on a single charge. It sells for around $200.00 and if you are going to be doing a lot of staining it is well worth the cost.
Hold the tip of the sprayer approximately eighteen to twenty-four inches from the concrete surface and spray onto the slab, being careful not to let the liquid drip out of the spray tip as this may leave visible drip marks on the concrete. There is no need to hold the sprayer closer to the ground unless you might be "working" an edge.
We recommend that you use a car wash brush with nylon bristles to gently scrub the concrete stain into the concrete but it is not necessary if you are applying the concrete floor acid stain yourself, just wet the concrete thoroughly with the stain. After the first coat is applied and has completely dried, a second coat can be applied if a darker color is desired. We recommend that you walk on the surface in clean socks or surgical booties so as not to leave “shoe prints” on the surface. The second coat of concrete stain should be allowed to work into the concrete for 1-2 hours.

H. Neutralizing the acid stain
Due to the unique nature of Artistic Decor Stains neutralization of the stain is not necessary as with most all other acid stains. Plain water will provide as much neutralization as is necessary. Just simply wet the floor, scrub lightly to loosen the slight amount of residue that remains and shop-vac to ensure you remove any residue, usually there is little if any residue.
Our stains and method of application will save you 1/3 of the labor involved with acid staining your concrete. I don't know about you but I'm all about saving time and money.
If you are using another brand of acid stain check with the manufacturer as to their recommended method of neutralization. Baking soda combined with water or a cup of ammonia in a 5 gallon bucket will usually do the trick.

Make sure that you shop-vac your floor no matter whose brand of stain you use. This is another step that the so-called experts don't advocate in the concrete floor acid stain application process, but it is essential to having a surface that your sealer can bond to permanently. Your floor may appear dry but we would recommend that you leave the floor overnight with the AC on if possible and a fan to circulate the air. The fan doesn't necessarily have to be directed onto the floor, this is just to get the air moving and get the moisture out of the area.

G. Application of Sealers
After the above step is completed you are ready to sealer your concrete. We recommend using a water-based sealer such as our Clear Cover WB sealer. This will provide you with a sealer that will protect the stained concrete and will increase the intensity of the color of the stained concrete. Normal water-based sealers do not increase the color intensity and will leave you with a "terra-cotta pot look". Two coats should be applied with Wooster 1/4 " nap Mohair blend paint roller, which are available from Lowe's. If you don't have a Lowe's close any quality paint store should have a comparable roller. Apply at a coverage rate of 250 - 300 square feet per gallon per coat.
We recommend that you apply three coats of wax as the last step in the concrete floor acid stain application process, to act as a sacrificial lamb for the sealer. A great wax to use is Zep High Traffic Floor Finish which available at Home Depot. The cost is around $15.00/gal and should be applied with a rayon blend mop which is also available at Home Depot. This will also provide your slip resistance as all waxes are manufactured to what is call "co-efficient of friction" of 0.05 or greater. This is the standard the government requires.
H. Maintenance (Low)
Floors treated with the concrete stain need only to be swept or cleaned when they become dirty.
I. Precautions
Acid Stains are a corrosive liquid and should be handled with caution. For more information, refer to the Artistic Decor Stains Material Safety Data Sheet. Respirators and goggles or safety glasses are recommended

J. Limitations and expectations.
Concrete floor acid stains will not hide cracks, blemishes, chalk lines (red and blue in particular) or other construction errors. The colors produced by the Artistic Decor Stains acid staining system will vary from surface to surface. Take the time to test the stains on your slab in an out of the way place to determine the color and the dilution you want to use. These color differences are dependent upon chemical makeup, lime content, porosity of the concrete, age of the slab, exposure to the elements, texture and color of the concrete, application methods, experience of the applicator and the number of coats applied. Some concrete surfaces cannot be successfully stained.