Ordering the right amount of material is one of the first questions every homeowner asks, and the math is simpler than you'd think. Here's how to figure out exactly what you need — and why ordering a little extra is always the right call.
The basic formula
Square footage ÷ coverage rate = gallons needed
That's it. The coverage rate is on the Technical Data Sheet (TDS) for every product. Here's what our products cover:
- Polyaspartic (RS Poly 90): 300 SF per 2 gal kit at 8 mil thickness (150 SF/gal)
- 100% Solids Epoxy (RS-EP-100/F): 300 SF per 3 gal kit at 10 mil thickness (100 SF/gal)
- MVB Primer (RS-MVB): 200 SF per gallon at 8 mil thickness
Step 1: Measure your floor
Measure length and width in feet. Multiply them together for square footage.
A standard two-car garage is roughly 20 ft x 20 ft = 400 square feet. A three-car garage is typically 30 ft x 20 ft = 600 square feet.
If your space isn't a perfect rectangle, break it into rectangles, calculate each one, and add them up. Don't forget to subtract any areas you won't be coating (raised platforms, built-in workbenches, etc.).
Step 2: Calculate gallons
Let's say you're doing a two-car garage (400 SF) with the double polyaspartic system (two coats of polyaspartic, no epoxy base):
First coat (polyaspartic): 400 SF ÷ 300 SF/kit = 1.3 kits → round up to 2 kits Second coat (polyaspartic): 400 SF ÷ 300 SF/kit = 1.3 kits → round up to 2 kits Total polyaspartic needed: 4 kits (8 gallons total)
Our RS Poly 90 comes in 2-gallon kits, each covering about 300 SF. For a 400 SF garage with two coats, 4 kits gives you comfortable coverage with a safety margin.
Step 3: Add a waste factor
Real floors aren't laboratory conditions. You'll lose material to:
- Mixing containers (a thin film always sticks to the bucket)
- Squeegee and roller absorption
- Edges and corners that need extra attention
- Uneven concrete that soaks up more material in low spots
Add 10–15% to your calculated amount. This is not optional — it's the difference between having enough material to finish the job and running out 30 square feet from the end with no way to match the batch.
Common project sizes
Here are quick references for the most common residential jobs:
Two-car garage (400 SF) — Double Poly System:
- 4 kits RS Poly 90 (8 gal total, 2 coats — each kit covers ~300 SF)
- Add MVB primer if needed: 1 kit (2 gal)
- Flake (if full broadcast): 40 lbs
Two-car garage (400 SF) — Full Flake System:
- 2 kits 100% Solids Epoxy (each 3 gal kit covers ~300 SF)
- 2 kits RS Poly 90 (topcoat — each kit covers ~300 SF)
- Flake: 40 lbs
- Add MVB primer if needed: 1 kit (2 gal)
Three-car garage (600 SF) — Double Poly System:
- 4 kits RS Poly 90 (8 gal total, 2 coats)
- Add MVB primer if needed: 2 kits (4 gal)
- Flake (if full broadcast): 60 lbs
Basement or shop (800 SF) — Double Poly System:
- 6 kits RS Poly 90 (12 gal total, 2 coats)
- Add MVB primer if needed: 2 kits (4 gal)
What happens if I run out mid-coat?
This is the scenario you want to avoid. If you run out of material halfway through a coat, you'll have a visible line where the wet edge dried before you could continue. This is called a "cold joint" and it's very difficult to fix. The only real fix is to sand the entire floor and start the coat over.
Always order at least one extra kit beyond your calculation. Unopened kits can be returned or saved for a future project. Running out mid-pour cannot be undone.
What about thickness?
The mil thickness is how thick the cured coating is, measured in thousandths of an inch. 8 mil = 0.008 inches.
Going thicker uses more material but gives you a more durable, longer-lasting floor. Going thinner stretches material but risks an under-built floor that wears through in high-traffic areas.
Stick to the recommended thickness:
- Polyaspartic: 8–12 mil per coat
- Epoxy: 10–12 mil per coat
- Primer: 6–8 mil
Don't try to save money by going thin. The material cost difference between 8 mil and 6 mil is maybe $30, but the durability difference is years of lifespan.
The bottom line
Measure your space, divide by the coverage rate, add 10–15%, and round up to the nearest kit size. When in doubt, order one extra kit. It's cheaper than redoing a floor because you ran short.