Coating a garage floor yourself in St. Louis comes down to three things: the right weather window, a properly prepped slab and enough material to hit full thickness. Here is how each one plays out locally.
Every kit ships from our shop in Queen Creek, Arizona, and comes with free phone support from the people who mix and pack it. Call 602.600.0781 with questions before, during or after your install.
St. Louis at a glance for epoxy work
| Typical July high | About 90°F |
| Typical January low | About 24°F |
| Average yearly snowfall | About 17 inches |
| Humidity | High in summer |
| Best pour window | Late May through mid September |
| Kits for a two car garage | 4 kits for 400 sq ft (1 kit = 100 sq ft) |
Temperatures and snowfall are rounded long term averages for the city and are meant for planning. Always check the forecast and measure your actual garage and slab temperature on pour day.
How St. Louis weather affects your epoxy pour
Summer afternoons in St. Louis average around 90°F, which puts many garages near or above the 90°F upper limit for application. Mid summer pours are possible if you start early and work in small batches, but spring and fall give you the full working time.
January lows near 24°F mean winter mornings can dip below the 41°F minimum. If you need to pour in the cold months, warm the garage for a day ahead so the slab, not just the air, is at temperature.
Summer humidity in St. Louis often climbs above the 65 percent limit, so check a hygrometer before you mix. Lower humidity days give the cleanest finish.
Occasional snow, around 17 inches in a typical year, still brings some salt and slush into the garage, and a sealed floor makes cleanup easy.
Best time of year to pour in St. Louis
For most St. Louis garages, the most forgiving window is late May through mid September. In that stretch you can usually count on the slab staying between 60°F and 85°F through the 72 hour cure, which gives you full working time and a consistent finish.
Prepping a St. Louis garage slab
Hot humid summers and salted winter roads are both hard on bare concrete. Many older St. Louis homes have alley garages with worn or painted floors that need grinding.
Before anything else, do the water droplet test. Sprinkle water on the bare concrete. If it soaks in within about 30 seconds, the surface is ready to grind and coat. If it beads up, there is a sealer, paint or contamination that has to come off first.
For St. Louis garages that have seen years of salt and freeze thaw, we strongly recommend a primer under the epoxy. It seals porous, weathered concrete and gives the coating a better bond.
Our full step by step process is on the installation instructions page.
Which kit fits your St. Louis project
Indoor quartz sand epoxy self leveling floor kit. This is the kit for garages, workshops, basements and other interior concrete, in Marble Grey, Desert Grey or Black. The quartz aggregate gives a thicker, more textured and more slip resistant surface than standard garage floor paint or thin water based epoxy. It is made for indoor use and does not have strong UV protection, so keep it out of direct, all day sun.
Outdoor washed stone quartz epoxy floor kit. With as much sun as St. Louis gets, patios, walkways and porches should get the outdoor system rather than the indoor kit. It comes in four stone colors and covers up to 100 square feet per kit. The washed stone finish lets water pass through, so it is not a waterproofing membrane. Over a basement or living space, a separate waterproofing layer is needed underneath.
Tools. To spread and finish the coating you need a 22 inch squeegee with pole, a 20 inch defoaming roller and an extension pole for the roller. Our epoxy tool kit adds a tool bag, spiked shoes for walking on the wet coat and five finishing trowels.
How many kits you need
One kit covers 100 square feet at the target thickness of about one eighth inch. No guessing. Measure the length and width of the floor, multiply, divide by 100 and round up. A one car garage is about 200 square feet and takes 2 kits, a two car garage is about 400 square feet and takes 4 kits, and a two and a half car garage is about 500 square feet and takes 5 kits. Do not stretch coverage, since a thin coat will not level properly.
Questions St. Louis customers ask
When is the best time to epoxy a garage floor in St. Louis?
For most St. Louis garages the best window is late May through mid September. You want the garage between 41°F and 90°F, ideally 68°F to 77°F, with humidity under 65 percent.
How much does a DIY epoxy garage floor cost in St. Louis?
One kit covers 100 square feet, so a standard two car garage of 400 square feet takes 4 kits. At current pricing that is $996 in Marble Grey or Desert Grey and $1,200 in Black. If you do not own them, add about $95 for the squeegee, defoaming roller and extension pole, plus primer if your slab needs it. Professional installs are often quoted around $4 to $10 per square foot, which puts the same garage at roughly $1,600 to $4,000.
Can I use the indoor quartz epoxy kit on a patio in St. Louis?
The indoor kit is made for garages, shops and interior floors and does not have strong UV protection, so it can yellow in direct sun. For patios, porches and walkways, use our outdoor washed stone kit. It covers up to 100 square feet per kit, and because the washed stone finish lets water pass through, it is not a waterproofing membrane.
How long before I can park on my new floor?
Light foot traffic is fine after 24 hours, the coating reaches full cure around 72 hours, and you can drive and park on it after about 5 days. In cooler St. Louis garages below 55°F, allow extra time.
Do I need a primer under the epoxy?
Primer is sold separately and is strongly recommended for older or porous concrete, slabs that were painted or sealed, floors with past moisture issues and any garage that sees heavy vehicle traffic. It seals the pores and gives the coating a stronger bond.
Can I put epoxy over a painted or sealed garage floor?
Not directly. Paint, sealers and old coatings keep the epoxy from bonding to the concrete. Do the water droplet test, and if water beads up, grind the old coating off down to bare concrete before you pour.
What is the difference between quartz epoxy and a flake floor?
A flake floor uses decorative vinyl chips broadcast into the coating for a speckled look on a smooth surface. Our system uses quartz sand aggregate, which gives a textured stone look with more grip underfoot. Both are epoxy based, but the finish and feel are different.
Do I have to grind the concrete, or can I acid etch it?
We recommend grinding. An angle grinder with a diamond cup wheel or a rented floor grinder gives the concrete a texture like 60 grit sandpaper that the epoxy can grip. Acid etching is less consistent and can leave residue behind, which is a common cause of peeling.
Ready to start your St. Louis garage floor
Talk to us about square footage, color and prep before you order. We are available Monday through Friday, 8am to 5pm Arizona time.
Nearby and similar climate guides: Kansas City, MO, Chicago, IL, Columbus, OH, Indianapolis, IN, Boston, MA. See all city guides.