An epoxy floor transforms a dusty garage into a showroom, but buying too little means a patchy finish and buying too much is money wasted. This calculator sizes the primer and epoxy order for your floor area and coat count.
Floor Dimensions
ft
ft
Coating Details
coats
Scenario: You're coating a 22 ft x 20 ft workshop floor with 2 coats of epoxy plus primer.
Result: Floor area is 440 sq ft. You need 1.76 gallons of primer and 3.52 gallons of epoxy (440 x 2 / 250 = 3.52).
A 2-car garage is 400-500 sq ft. With 2 coats at 250 sq ft per gallon, you need 3-4 gallons of epoxy plus 2 gallons of primer.
Yes, primer improves adhesion and reduces the risk of peeling. It also seals the concrete to prevent moisture vapor from bubbling the epoxy. Skip primer only if the epoxy product explicitly states it is self-priming.
5-10 years in a residential garage before needing a recoat. Surface preparation is the single biggest factor in longevity. Skimp on prep and you'll be scraping it off in two years.
You must remove old paint or coatings first. Epoxy bonds to the concrete itself, not to paint. Grind or strip the old finish, etch the surface, and let it dry completely before applying primer and epoxy.
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