When painting concrete , what must one do to the concrete to get the paint to properly adhere ?

First rule of painting-Clean, Dry, Dull. If the concrete is all three of those you are in good shape to prime or paint. There are other considerations. 1)How old is the concrete? concrete must be cured a minimum of 30 days. 2)Was some kind of curing agent used on the concrete? Simply sprinkle with water. If it beads up then there is some type of sealer present. If the water penetrates the concrete and it changes color you are in good shape. Test several areas. 3)What is the Ph of the concrete. 100% acrylic paints will handle a ph in the range of 10 to 7-(7 is neutral). Several people have mentioned acid washing. That is only necessary if the concrete is not porous. Never let an acid dry completely on concrete. You will never get all the residue off if you do. If you need to acid wash use Phosphoric acid or Muriatic acid, follow the recommended reduction rate for the acids as they come in different concentrations. You don't mention whether the surface is vertical or horizontal interior or exterior. You didn't ask for product recommendations either, but I will give you a few guidelines. Oil based paint is out. There is actually a chemical reaction that occurs(saponification) with the alkyd pigment and the ph that is in the concrete. Use 100% acrylic latex paint. That will give you the best adhesion and longest color and gloss retention. If you want to give yourself the best finish possible use a ph resistant primer. Primers are formulated differently for different purposes. Make sure you get one that is for your purpose.When painting concrete , what must one do to the concrete to get the paint to properly adhere ?
Clean the area thoroughly by using a strong detergent and or mild muriatic solution, also best to use a pressure washer to lift stubborn stains. After the area has been thoroughly cleaned, wait a day or two for the concrete to dry up and get any moisture out from the concrete. After, prime the area with a concrete coating or if not readily available latex primer should do well, to seal in concrete and to make the paint match evenly. Let dry again. Prepare the paint, latex paint should do. Do not use oil-based, since it will take a long time to dry and moisture can seep in a create bubbles. Do not shake the paint, but have it stirred, to prevent air bubbles from getting into the paint. Then apply the paint in thin coatings. Do not try to paint it fast by using lots of paint at once. Stick with thin coatings. Let dry. Paint again. Continue process... 3 coatings should suffice. During drying phases, look over for any signs of bubbling. If there are bubbles, scrap the paint in the bubbled area only, and re-prime it and paint again.When painting concrete , what must one do to the concrete to get the paint to properly adhere ?
First you have to wash it down to remove any dirt or mud. A steamer or water jet blaster would be ideal for this. Then when dry, a good scrubbing down with muriatic acid to 'etch' the concrete. This will make the paint stick better.


Because of the amount of work required to prepare the concrete I suggest that you use a good quality concrete paint else, all your hard work will end up being for no reason.
there is a special paint. you can find what you need at the hardware store.
You must first put an initial batch of paint, usually a flat white color paint, then after the first paint has dried you can now paint the GLOSSY paint with the color of your choice... use latex thats comes in two types FLAT and GLOSSY
Wash thoroughly first. Paint or spray it with a mild acid like white vinegar, then let dry. Apply regular paint. You can also buy special pre-treatment at paint or hardware store, but it costs more and doesn't seem to work any better.
You need to wash it first with TSP or muriatic acid. I recommend the TSP as muriatic acid is hell to work with. After that you prime it with a paint intended for that application.

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