Epoxy vs. Polyaspartic Shop & Garage Floors in the Inland Northwest: 9 Real Questions, Answered With Spec-Sheet Data
Owners who finish a new shop slab or a garage usually ask about a floor coating next. In Spokane the biggest variable isn't the brand. It's temperature. These are the questions we hear most, answered with manufacturer technical data sheets and published 2026 costs instead of sales talk.
Quick comparison
- Application temperature: Epoxy (example: Benjamin Moore GarageGuard): 50–90°F. "Will not cure at surface temperatures below 50°F" (1); Polyaspartic (example: ArmorGarage Polyaspartic 80): 30–90°F. Extreme cold slows cure (2)
- Back in service: Epoxy (example: Benjamin Moore GarageGuard): Several days (see TDS); Polyaspartic (example: ArmorGarage Polyaspartic 80): 24 hours for vehicle traffic (2)
- New concrete wait: Epoxy (example: Benjamin Moore GarageGuard): 30 days minimum (1); Polyaspartic (example: ArmorGarage Polyaspartic 80): Per manufacturer, test moisture
- Installed cost, 2026: Epoxy (example: Benjamin Moore GarageGuard): $4–$10 / sq ft (3); Polyaspartic (example: ArmorGarage Polyaspartic 80): $5–$12 / sq ft (4)
- 2-car garage (400–576 sq ft): Epoxy (example: Benjamin Moore GarageGuard): about $1,600–$5,760; Polyaspartic (example: ArmorGarage Polyaspartic 80): about $2,000–$6,900
These two products are examples. Different epoxies and polyaspartics have different limits, so always follow the data sheet for the product actually being installed.
1. "Can I epoxy my garage floor in a Spokane winter?"
Usually not without heating the space. The GarageGuard epoxy data sheet recommends application between 50 and 90°F and says the product will not cure at surface temperatures below 50°F (1). What matters is the slab temperature, not the air temperature. A slab in an unheated garage in January can sit well below the air temperature at midday. If the space can be heated and held at temperature through the cure, a winter install is possible. Otherwise, schedule epoxy for late spring through early fall.
2. "Then why do some installers coat floors in November?"
They're often using a polyaspartic or another fast-cure, low-temperature system. ArmorGarage's Polyaspartic 80 data sheet lists application from 30°F to 90°F, with the caveat that extreme cold slows cure (2). Other polyaspartics need 50°F or more, so ask which product is being used and request its data sheet.
3. "What's the dew-point rule?"
Coating manufacturers warn against applying when the surface temperature is close to the dew point, because condensation on the slab ruins adhesion. GarageGuard's data sheet says not to paint if the surface temperature is within 5 degrees of the dew point (1). Spokane-area garages often have cold slabs and warm, humid air from a vehicle coming in, so check with an inexpensive surface thermometer before work starts.
4. "I just poured a new shop slab. How long do I wait?"
For GarageGuard on never-coated floors, at least 30 days of concrete cure (1). Many pros also run a moisture test before coating. If you're pouring a new slab in a steel building and plan to coat it, tell your concrete contractor up front. Finish and curing choices, like curing compounds or sealers, affect how well a coating bonds later.
5. "What does it cost?"
HomeGuide's 2026 guides list professionally installed epoxy at $4–$10 per sq ft and polyaspartic at $5–$12 per sq ft (3, 4). Here's the math for common sizes:
- 2-car garage: Size: 24x24 = 576 sq ft; Epoxy ($4–$10): $2,304 – $5,760; Polyaspartic ($5–$12): $2,880 – $6,912
- 3-car garage: Size: 36x24 = 864 sq ft; Epoxy ($4–$10): $3,456 – $8,640; Polyaspartic ($5–$12): $4,320 – $10,368
- 30x40 shop: Size: 1,200 sq ft; Epoxy ($4–$10): $4,800 – $12,000; Polyaspartic ($5–$12): $6,000 – $14,400
- 40x60 shop: Size: 2,400 sq ft; Epoxy ($4–$10): $9,600 – $24,000; Polyaspartic ($5–$12): $12,000 – $28,800
Repairs to cracks, spalls and oil-soaked spots are usually extra.
6. "Which one handles magnesium chloride and road grime better?"
Neither manufacturer we cited publishes a specific deicer-resistance rating in the sections we reviewed, so we won't make one up. Ask your installer for the chemical-resistance table in the product data sheet and look for road salts and automotive fluids. In practice, the topcoat and the texture (flake broadcast and anti-slip additive) matter as much as the base chemistry.
7. "Will it be slippery when snow melts off the truck?"
Smooth, glossy coatings can be slippery when wet. A full flake broadcast or an anti-slip additive in the topcoat helps. Ask for a textured topcoat sample and test it wet.
8. "Should I fix cracks first?"
Yes. Coatings follow the slab, so active cracks and heaved panels will come through. Settled sections may need leveling or replacement before coating. Concrete repair and flatwork comes first, coating second.
9. "Polyaspartic or epoxy: which should I pick?"
- Choose polyaspartic if you need the floor back in a day, are installing in shoulder season, or want a UV-stable topcoat near a big open door.
- Choose epoxy if budget comes first and you can schedule a warm stretch with several days of downtime.
- Many systems combine them: an epoxy base with a polyaspartic topcoat. Ask for the full system on the quote.
Before-you-coat checklist
- Slab is at least 30 days old, or per the product's TDS (1)
- Surface temperature is within the product's range and at least 5°F above dew point
- Cracks, spalls and settled panels are repaired
- Moisture test is done
- Product data sheet is in hand (cure times, chemical resistance)
- Texture or anti-slip topcoat is chosen
Planning a new shop floor?
Raven Buildings pours shop and garage slabs and can plan the finish for the coating you want. Call 509-350-2016 or request a quote.