In this blog, we’re responding to a great question posed by one of our potential customers pertaining to the yellowing of epoxy coatings. Yellowing may occur for several reasons, but in this case, our prospect was referring to the yellowing that occurs at points where the tires of a parked car rest on a coated garage floor.
A Quick Sidebar
On our website, https://www.garagefloorcoating.com/, we invite our customer prospects to ask us any question pertaining to epoxy coatings in general…or any question pertaining to their specific coating project. On the same website, we provide our potential customers with a “10 Important Questions” slick to help them ask the right questions (with answers) when obtaining bids from any floor coating company.
Why is this Important?
When seeking bids from multiple contractors, asking the right questions is critical to ensuring you hire a professional floor coating company. There are hundreds of contractors that install epoxy floor coatings…many are suspect. They’ll use low-grade products, or poorly prepare the concrete, or simply lack knowledge or technique. The only way to flush out a disreputable contractor is to ask questions and know what the answers should be.
Click below to read our “10 Important Question’s” (and answers) slick:
Back to Our Customer’s Question
This is the actual question posed by our customer prospect. The question refers to a top coat applied to his neighbor’s garage floor that is “yellowing” where the car tires rest on the top coat.
I am looking for an epoxy floor for my garage and shop. As you pointed out, a home owner should ask questions about the products being used on their floor and expect honest answers. My neighbor had his garage floor done a year ago with a 100% solids epoxy with the decorative flakes and they used a two part urethane top coat.
The floor looked fantastic but now the top coat is showing yellowing stains where the tires from the car sit on it. This stopped me from moving forward with my floor until I can get an answer. I do NOT want my floor showing yellow stains from tires and your post says it is from urethane top coats??? So what top coat do you use that does not yellow and do you warranty it from staining?? I want to read up on all the products being used on my floor.
Why does yellowing occur?
Tire marking or “hot tire pickup” on concrete coatings is caused by a phenomenon called “plasticizer migration”. The rubber used to make high-quality car tires contains plasticizers to make the tire softer and improve traction. When the car is driven, the tires heat up, causing the plasticizers to soften and leach out of the rubber.
When a hot tire is parked on concrete sealed with a polyurethane topcoat, the plasticizers migrate into and discolor the topcoat. Why? Because polyurethanes contain plasticizers too! As like attracts like, the plasticizers leach into the polyurethane coat and produce the unsightly yellowing.
How do you prevent it?
Simple. Never use a polyurethane as a topcoat in a garage – ever (or as a topcoat for your driveway if that’s where you intend to park your car). Polyurethanes, like GarageFloorCoating.com’s Poly Pro, are great topcoats for low-odor interior installations or exterior patios…but not where vehicles are parked for extended periods.
Instead, use a polyaspartic hybrid as the topcoat in garages (like GarageFloorCoating.com’s Poly Hybrid). This “hybrid” between an epoxy and polyurethane has high solids content and extreme chemical & UV resistance…and doesn’t “amber” when exposed to car tire plasticizers.
So the friend’s garage turned yellow simply because the wrong topcoat was applied. In the business of floor coatings, knowledge is key. Make sure you only hire professional floor coating companies.
How? Use our “10 Important Questions” slick to help you make the right choice.
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