Quick Answer
The amount of epoxy needed for 400 square feet depends on the thickness of the epoxy coating. On average, you will need:
- 2 gallons of epoxy for a 1/16″ coating over 400 square feet
- 4 gallons of epoxy for a 1/8″ coating over 400 square feet
- 8 gallons of epoxy for a 1/4″ coating over 400 square feet
Calculating How Much Epoxy You Need
To calculate how much epoxy you need for a project, you first need to determine:
- The square footage of the area you want to coat
- The recommended coverage rate of the specific epoxy product you plan to use (in square feet per gallon)
- The thickness of the coating you want to achieve
With this information, you can use the following formula:
Square footage x Coating thickness x 1 gallon / Coverage rate = Gallons needed
Let’s break this down into the steps to determine how much epoxy you need for 400 square feet:
1. Determine the square footage
For this example, we know the square footage is 400 square feet.
2. Choose a coating thickness
Epoxy coatings typically range from 1/16″ to 1/4″ thick. The thicker the coating, the more epoxy will be required.
Common epoxy coating thicknesses are:
- 1/16″ – For a thin or primer coat
- 1/8″ – For a standard application
- 1/4″ – For a thick or self-leveling application
For this 400 square foot project, let’s calculate the epoxy needed for three options – 1/16″, 1/8″, and 1/4″ thick coatings.
3. Look up coverage rate for the epoxy
The coverage rate or spread rate refers to how many square feet a gallon of epoxy will cover at the recommended thickness. This varies by specific epoxy product.
For example, a typical 2-part epoxy may have a coverage rate of:
- 200 sq ft per gallon at 1/16″ thickness
- 100 sq ft per gallon at 1/8″ thickness
- 50 sq ft per gallon at 1/4″ thickness
We’ll use these typical coverage rates for our calculations.
4. Plug the numbers into the formula
Now we can plug our numbers into the formula:
Square footage x Coating thickness x 1 gallon / Coverage rate = Gallons needed
For 1/16″ thickness:
400 sq ft x 1/16″ x 1 gallon / 200 sq ft/gallon = 2 gallons
For 1/8″ thickness:
400 sq ft x 1/8″ x 1 gallon / 100 sq ft/gallon = 4 gallons
For 1/4″ thickness:
400 sq ft x 1/4″ x 1 gallon / 50 sq ft/gallon = 8 gallons
Summary
Based on the calculations above, for a 400 square foot project you will need:
- 2 gallons of epoxy for a 1/16″ coating
- 4 gallons of epoxy for a 1/8″ coating
- 8 gallons of epoxy for a 1/4″ coating
Of course, these numbers are based on typical epoxy coverage rates. Be sure to read the product specifications for your particular epoxy brand and type to get the exact coverage rate, which may vary.
Factors that Affect Epoxy Coverage Rates
While the formula above provides a good estimate, there are several factors that can affect the actual coverage rate of epoxy:
1. Surface Porosity
If the surface you are coating is very porous, rough, or uneven, the epoxy will soak in and cover less area, reducing the coverage rate. Porous concrete or wood surfaces require more epoxy than smooth, sealed surfaces.
2. Application Method
Applying epoxy with a roller, brush, or squeegee can reduce coverage rates compared to pouring self-leveling epoxy. More epoxy adheres to the application tools versus the surface.
3. Number of Coats
Most epoxy applications require two coats – a primer coat and a topcoat. More coats means you need more epoxy.
4. Mixing Ratios
Epoxies consist of a resin and hardener that must be mixed in the proper ratios. An error in the mixing ratio can affect curing and change coverage rates.
5. Temperatures
Cold temperatures can slow the curing time of epoxy, while warm temperatures speed it up. This impacts how far the epoxy will spread.
6. Waste
It’s always a good idea to add 10-15% extra epoxy to account for material that is wasted or discarded in the mixing and application process.
Tips for Estimating Epoxy Needs
To ensure you purchase enough epoxy for your project without wasting excess material, keep these tips in mind:
- Add up the total square footage you plan to coat – measure the length x width of each area.
- Read the technical specifications for your specific epoxy type and brand to get accurate coverage rates.
- Measure the recommended epoxy thickness needed for your project.
- Use 1/8″ thickness for standard flooring applications.
- Use 1/4″ or more for a thick, self-leveling floor coating.
- Add 10-15% extra epoxy to account for uneven surfaces, mixing losses, and application waste.
- Only mix as much epoxy as you can apply during the working time.
- Check ambient temperature – colder means slower curing and more spread.
- Apply to properly prepared surfaces – cleaned, etched, and primed if needed.
Following these guidelines and the coverage formulas above will help you calculate the right amount of epoxy resin and hardener you’ll need for a 400 square foot garage, basement, or other flooring project.
Purchasing Epoxy Resin and Hardener
When purchasing your epoxy for a DIY project, keep these tips in mind:
- Buy the resin and hardener from the same brand.
- Select the proper formulation – 100% solids for most floor coatings.
- Choose the right size – 1-gallon kits are good for small projects.
- Pick a low odor, low VOC formula for indoor use.
- Get clear resin if you don’t need color.
- Buy colored tint packs to add color if desired.
- Choose the right hardener – slow, standard, or fast cure.
- Buy extra supplies – roller covers, squeegees, tape, etc.
When estimating how much to buy, it’s always better to have too much than not enough. Having extra epoxy allows you to add additional coats to achieve a thicker or glossier finish. Unmixed leftover epoxy resin and hardener has a long shelf life if properly stored.
Hiring a Professional Epoxy Flooring Contractor
While a small DIY epoxy project is certainly doable, for larger commercial jobs or surface areas greater than 500-1000 square feet, it’s best to hire a professional epoxy flooring contractor.
The benefits of hiring a professional include:
- Knowledge of proper epoxy products, mixing ratios, and coverage rates
- Proper surface preparation and cleaning
- Access to commercial-grade application tools
- Faster application for large jobs
- Consistent, professional results
- Experience with creative application techniques like color patterns, chips, and topcoats
Professional epoxy flooring can be customized with color, additives, and topcoats and seamlessly installed for commercial, industrial, and residential settings. Most pros provide free quotes after assessing your space.
How Much Does Professional Epoxy Flooring Cost?
Hiring professional epoxy floor installers typically costs $3-$9 per square foot depending on:
| Floor size | Smaller jobs under 500 sq ft cost more per sq ft. Larger jobs over 1000 sq ft cost less per sq ft due to economies of scale. |
| Surface preparation | Cleaning, etching, repairing cracks or chips adds labor costs. |
| Coating thickness | Additional coats or thicker epoxy increases material costs. |
| Color and effects | Additives like color flakes/chips or extra topcoats add cost. |
| Location | Overhead and wages influence installer rates regionally. |
Most epoxy flooring installers provide free, no-obligation quotes after visiting your space. This allows them to assess the specifics of your project and needs.
DIY Epoxy Flooring Costs
For DIY epoxy floor coating, your main upfront costs will be:
- Epoxy material – Resin and hardener costs $50-$100 per gallon.
- Tools – Roller covers, paint brushes, squeegees, etc. can run $50-$150.
- Surface preparation – Floor cleaners, etchers, or repair compounds if needed.
- Additional coatings – Primers, color tints, chips or topcoats add costs if desired.
Beyond material costs, also factor your time and labor for surface preparation, application, and cleanup.
Cost to Epoxy a Garage
For a typical 400-500 sq ft garage, professional epoxy floor coating costs $1200 to $2500 installed.
DIY epoxy garage kits run $300-$700. This covers 2-car garage floors without any color additives or topcoats.
The most inexpensive option is a 1-part epoxy paint which starts at around $80 per garage kit. However, the finish and durability is lower compared to 2-part epoxy.
Cost to Epoxy a Basement
An average 700 sq ft basement costs $2100 to $4000 for professional installation.
DIY epoxy basement kits run $400-$900. This provides enough epoxy for one coat without decorative options.
For basements that see water seepage, look for moisture-tolerant water-based epoxies. 100% solids epoxy won’t adhere as well to damp concrete.
Cost to Epoxy Commercial Floors
For retail, industrial, or restaurant floors, professional epoxy coating typically costs:
| 500 sq ft | $2500-$4000 |
| 1000 sq ft | $4000-$7000 |
| 3000 sq ft | $12,000-$20,000 |
Commercial installations should always be left to epoxy coating professionals, as they require industrial-grade application equipment plus extensive experience with surface preparation and installation.
Epoxy Floor Coating Pros and Cons
Epoxy floors provide a glossy, attractive finish that is also durable, waterproof, and chemical resistant. However, some drawbacks to consider include:
Pros:
- Glossy, professional finish
- Wide range of color options
- Strong and durable for heavy use
- Waterproof surface
- Easy to clean
- Resists oils, chemicals, impacts
- Lasts for many years
Cons:
- Higher upfront cost than other flooring
- Surface requires preparation for proper adhesion
- Pot life limits working time for installation
- Strong fumes during application
- Installed best in moderate temps
- Challenging DIY project over 400+ sq ft
For garage, basement, and commercial floors seeing heavy traffic and abuse, the pros often outweigh the cons with epoxy. Proper installation is key to achieving long-lasting results.
Conclusion
When planning an epoxy floor coating project, give careful consideration to the square footage you need to cover and the coating thickness desired. Measure accurately and read manufacturer specifications to calculate how much epoxy resin and hardener is required. For DIY installations, start with small rooms under 400 sq ft and allow plenty of working time. Larger projects are often best left to experienced professional installers who can efficiently apply commercial-grade epoxy for consistent, attractive results. With some planning and preparation, an epoxy floor coating can provide long-lasting durability, easy maintenance, and a high-end aesthetic.
