Selected Answers

From Jerry Trevino of Protective Liner Systems on September 12, 2012:
     This question is too broa ...read more      This question is too broad to answer; however, the factors include how old is the new concrete, the composition of the concrete, water to cement ratio used, type of curing used such as heat, admixtures, sunlight, temperature of curing period, moisture of curing environment, placement methods used, curing agents if any used, chemical resistance of coating required, aesthetic requirements, life of coating expectancy, limitations on surface prep methods, purpose of the coating application, temperature exposure, sunlight exposure, control and/or expansion joint considerations,etc. I am sure there are a many more factors to consider.

From John Fauth of ChemMasters, Inc. on July 17, 2012:
     If the concrete is uncure ...read more      If the concrete is uncured and freshly placed, you may wish to choose a coating with curing properties meeting ASTM specifications (ASTM C 309 or ASTM C 1315). If the concrete is cured, it would be important to know by what means in order to determine if removal of a curing compound or additional surface preparation is required. Of course, surface preparation is essential for any concrete coating... rely upon the project specification and thoroughly understand the coating manufacturer's recommendations to ensure they are consistent. Same goes for application, where it may be necessary to use a primer, monitor slab and ambient temperature, humidity, dew point, the weather forecast, and a host of other factors.

From Kurtis Gundersen of KGP coatings on July 16, 2012:
Use latex or epoxy. Oil-based paints saponify due ...read more Use latex or epoxy. Oil-based paints saponify due to the alkalinity of the concrete materials.

From Larry Stephans of Sabur Technologies on July 17, 2012:
     Many factors come into pl ...read more      Many factors come into play when selecting concrete coatings. Start with service: Is this a concrete tank in which the coating will be immersed? Then consider the other conditions of this service such as temperature, chemical composition of contained material, etc. If the concrete is a floor, consider such parameters as traffic load, exposure to chemicals from splash and spill, cleaning, etc. Once you define the service, then look at coating types. Epoxies are probably the most common coating type, but there are new products coming to market seemingly every day.

From Joe Greiner of Odle, Inc. on September 10, 2012:
To answer this question you need more information. ...read more To answer this question you need more information. What process or environment is the concrete going to endure? Is it a new or existing structure? Do we need to worry about crack bridging and movement? Epoxies do have the best adhesion to concrete and frequently are used as a primer in coating systems.

From James Albertoni of CA Department of Water Resources on July 19, 2012:
 Don't forget to address hydrostatic pressure ...read more  Don't forget to address hydrostatic pressure if the concrete is in contact with soil. If there is high groundwater on the soil side of the concrete and no moisture barrier or waterproofing on the soil side, the hydrostatic pressure can cause severe failures of most any coating system.

From Mark Schilling on July 17, 2012:
The question is incomplete. It only considers the ...read more The question is incomplete. It only considers the nature of the substrate to which the coating is to be applied. The much larger question is - what is the coating supposed to do for you other than "stick?" Epoxies can provide high build and good chemical resistance. but they do not weather well and they may not look good after a while. Latex paint will likely weather better, but you will need multiple coats to cover and the chemical resistance may be inadequate. In any case - beware. Some latex paints are subject to saponification. If you go with a latex paint, make sure it is a 100% acrylic. Modifications from that baseline can build-in a susceptibility to saponification. I have seen that problem many times on homes where the exterior paint is regularly wetted by the lawn and garden sprinkler system.