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Garage Coatings Math: When 3 is Greater Than 5

Before anyone sends me flaming responses about how the whole numbers 4 and 5 are greater than 3, be sure that I know my discrete mathematics. I actually have a Science degree that includes a minor in Mathematics. While I don’t remember my abstract ring theory from my senior year of undergraduate work, I’'ve not forgotten what I learned in elementary school.

3 layer coatingWhat I'’m talking about is how some of our competitors, most in Maryland, market “5 layer” systems to convince homeowners that their garage coatings are somehow better than our 3 layer decorative chip coatings due to the sheer number of coatings layers.  But, a savvy consumer needs to look at the total garage floor coating’s thickness to determine if 5 is really better than 3. Let’s take a look at how coatings are measured.

Coatings are measured in MILS for their film thickness.   There is the Wet Film Thickness (WFT) and Dry Film Thickness (DFT).   Some coatings shrink during their curing process, so a coating layer applied at 5 MILS WFT may cure down to 3 MILS DFT (that means it shrank by 40%). 

A coating system can have many layers applied to create the total thickness.    What matters is the total of the layers’ Dry Film Thickness.   The chart below shows how our system, while only 3 layers is actually 50% thicker than some of our competitors’ 5 layer systems.

Comparison of Systems

Our 3 Layer System

Their 5 layer system


Primer – 2 MILS

Self-Priming Base coat – 10 MILS

Base coat – 3 MILS

Chips – 5 MILS

Chips – 5 MILS

Top coat – 9 MILS

1st Top coat – 3 MILS


2nd Top coat – 3 MILS

Approx. Total Thickness:   24 MILS

Approx. Total Thickness:   16 MILS

Why does total coating thickness matter?

1)     A more substantial primer/base coat allows for more materials to penetrate or “wet out” the floor, giving greater bond to the concrete. Weak bond strength leads to peeling under hot tires, similar to the problems found with all of the Do-It-Yourself epoxy coating kits.

2)     A more substantial base coat better holds the decorative chips. If there is not enough material to bind the chips, the floor will take on a scattered, amateur look.

3)     A thicker topcoat allows for greater normal wear and tear – equating to more years without the need to install another, new top coat. Longer coatings life is a better return on investment.

4)     A thicker topcoat allows for the topcoat to be rejuvinated without damaging the chip layer or replacing the coating system altogether.  Under normal conditions, professionally installed garage floor coatings should not need replaced, just a facelift every decade or so.

5)     When multiple layers are installed in one day (as is usually the case with 5 layer systems), the materials have to setup very quickly which decreases bond strength between the coatings layers. Decreasing bond strength between chemical layers means the coatings may not peel all the way down to the concrete, but they will allow for premature damage to the overall garage flooring system.

Guide to Garage Coatings
Then, why do these companies chose to install these 5 layer chip systems in residential garages?

1)     They use it as an excuse to charge more than other garage floor coatings companies.

2)     They use materials whose total cost are cheaper, whether it’s due to the cost from the manufacturer or because they are thinning out materials beyond the manufacturers recommendations (using cheap solvents or water, depending how the material is “thinned”).

3)     They do not have a long term business plan – as their long term customer base will have issues that will increase operating costs and decrease their customer satisfaction.

three layer garage floor coatingDoes this mean Stronghold Floors does not have systems that have more than 3 layers?  Not at all.  We have systems which are 4 or more layers, but they are typically used for exterior concrete or commercial/industrial systems with differing requirements than the typical residential garage floor coating.

One Last Note

If you are thinking about a Do-It-Yourself garage epoxy kit from a big box store, your system will be even thinner and weaker.   Typical DIY kits have a total average thickess of 4 to 5 mils. That is approximately 20% of our system and not even ½ as thick as just one of our layers.   

Check out this blog before you go DIY with your garage floors.  

 Editor's Note: This post was originally published on June 3, 2013 and has been completely revamped and updated for accuracy and comprehensiveness.