From tools and materials, to set up, preparation, application, and clean up, Thermal-Chem breaks down exactly how to apply epoxy flooring. 

Follow our 7-step guide to learn how to install epoxy floors and please keep in mind that applying Thermal-Chem’s portfolio of high-performance concrete coatings can be difficult if the applicator is not well informed. 

Please check our Technical Data Sheets, or contact your Thermal-Chem representative for any questions.

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Equipment Needed for Epoxy Floor Install

1. • Flat or notched rubber squeegee

1. • Extension pole

1. • 3/8” nap non-shed roller covers (9” for small jobs, 18” for larger projects)

1. • 2” chip brushes for “cutting in” around edges and columns

1. • Rags, disposable gloves, trash bags, tape

1. • Low-speed drill (extra batteries if using cordless)

1. • Proper mix blade-Jiffy blades are highly recommended

1. • Mix area protection-cardboard or drop cloth

Conditioning Materials

1. Colder Temperature Projects
   (<55 Degrees F) Colder resinous materials when stored in colder temperatures may be more difficult to apply due to an increase in the products viscosity.

1. Warmer Temperature Projects
   (>75 Degrees F) Resinous coatings create heat during the curing process. When materials are stored in warmer conditions they will “kick” or begin the cure process quicker, making application and working times decrease. Storing the Part B or hardener in a cooler environment will help increase working time.

Setting Up a Mix Station

Your mixing station is another important variable in the epoxy floor equation. Ensure you do your due diligence with these items below.

1. FULLY READ the Thermal-Chem product Technical Data Sheets (TDS) –
   There are many variations of mix ratios between products and manufacturers so make sure to do this BEFORE making the first batch.

1. Use proper PPE (personal protective equipment)
   Wear safety glasses, gloves, and arm protection (long sleeve shirt) to prevent products from coming in contact with skin.

Mixing of Products

Mixing Epoxy comes with a number of rules to follow. Keep these in mind. 

1. • Always pre-mix the pigmented epoxies.

1. • Mix using a low-speed drill. If materials are mixed too fast, air can be whipped into the product leading to bubbles forming on the floor. Avoid creating a vortex with the mixing paddle.

1. • Pour the hardener into the bucket first and then the resin into the hardener. Hardeners have a lower viscosity and do a better job of “wetting” the mixing pail.

1. • Understand the difference between “pot life” and “working time”.

Pot-Life – the amount of time the epoxy is usable once a curing agent comes in contact with a resin in a mixing container.

Working Time – the time after the products are properly mixed (usually 3-4 minutes, check TDS) and distributed onto the floor until the time when the products begin to set-up or become difficult to use due to an increase in viscosity.

1. • Mixes that are made in larger mixing containers such as a 5-gallon bucket will begin to cure quicker due to the mass of both components. For example, a 5-gallon mix will begin to “kick” quicker than a mix made in a 5-quart mixing container.

1. • Epoxy Products – once mixed thoroughly should be poured onto the surface in ribbons to allow the applicator more working time.

1. • Make sure to scrape out each measuring bucket fully and properly.

1. • Polyurea/Polyaspartic Products – once thoroughly mixed should remain in the mixing container and only poured onto the floor in an amount the applicator can properly spread in 10-15 minutes. (This is exactly opposite of epoxy products)

1. • Make sure all products to be used SDS (Safety Data Sheets) are available on each jobsite.

Applying Resinous Products

1. • Pour mixed product onto floor surface in ribbons (around perimeter) DO NOT FLIP MIX BUCKET USED ONTO THE PROJECT FLOOR TO TRY AND CAPTURE RESIDUAL MATERIALS. THIS WILL IN MOST CASES LEAVE A SPOT OF UNMIXED MATERIAL CREATING A SOFT SPOT.

1. • Using the squeegee pull the materials across the floor surface at the approximate desired thickness. The squeegee should be held at a 45-degree angle with medium pressure.

1. • Saturate the roller cover in the mixed product. This process of “loading” the roller cover will help prevent air bubbles in the coating applied.

1. • Using the saturated roller cover, roll out the materials. (a wet film gauge is a handy tool for applicators to use to check the mil thickness of materials applied.)

1. • Back-roll entire surface. This will be the method to ensure the liquids just applied are evenly applied.

1. • Typical Coverage Rates* for Thermal-Chem’s high performance concrete coatings:

1. ◦ 100 square feet per gallon will yield a nominal 16 mils

1. ◦ 160 square feet per gallon will yield a nominal 10 mils

1. ◦ 200 square feet per gallon will yield a nominal 8 mils

1. *These are based on using 100% solids products

Clean Up

Everyone’s favorite part of a project, clean up! 

1. • Clean application tools and mixing blade with a solvent such as xylene or acetone.

1. • Remove any tape used for edges, used buckets, roller covers etc., dispose of properly.

Applying Subsequent Coats

1. • If applying an additional coat this should be completed within 24 hours. If it’s been more than 24 hours, the surface must be lightly abraded to ensure proper adhesion.

Applying Thermal-Chem’s portfolio of high-performance concrete coatings can be difficult if the applicator is not well informed.  Please check our Technical Data Sheets, or contact your Thermal-Chem representative for any questions.

Get in Touch with Thermal-Chem Today

Well, since now you know how to do epoxy floors, I guess we should be on our way. 

Just kidding. 

If you still have any issues or need the Thermal-Chem team to help, please reach out to us for whatever it might be. 

Thermal-Chem provides a number of high quality products for all of your projects needs. Find your Polyaspartic or Epoxy coating on our site today!  

Is Your Concrete Properly Prepped for Epoxy Coating?

This test method can be used to determine the cleanliness of a concrete surface for the adhesion of epoxy coatings, epoxy overlays and areas requiring patching with epoxy. It can also be used to test the adhesion of the finished epoxy system to the concrete surface. This is a shear test method. For a full breakdown of everything you’ll need to ensure success, check out our post on preparing concrete for epoxy.

The Simple Cup Adhesion Shear Test will indicate whether:

• The concrete surface is clean and sound enough to allow adhesion of the polymer to the surface.
• The surface preparation process has or has not produced the desired results.
• The finished epoxy coating or overlay has an adequate bond to the concrete.

Equipment and Materials Needed:

• Non-Styrofoam 8 oz. paper cups of the type used for hot coffee.
• Dry, clean silica sand.
• One (1) mixing tool. Spatula or 1 in. wide margin trowel.
• Method of measuring small quantities of epoxy and sand. Gram scale for weighing, or volume measuring cups if the product is available as a volume measurement.
• Neat epoxy components.
• A 2 lb. hammer.
• When testing for adhesion of the finished system, a concrete core cutting drill and bit with a diameter of 2.75 in. will be required.

Description of Test:

1. Clean the concrete utilizing the same process specified for the project, following the polymer manufacturer’s written guidelines for surface preparation.
2. When oil or chemical spills have occurred, mark those locations on an accurately detailed measured plan. Select the areas with the heaviest contamination on the concrete as locations for testing in each sector.
3. For cleanliness and soundness, place one test per every 500 ft2. For adhesion of the finished epoxy system, place one test per every 1,000 to 4,000 ft2.
4. Evenly cut a 2 in. slice off of the top of an 8 oz. paper cup. The top portion will be used as a form to hold the epoxy in place during the curing process.
5. Using the same product that will be placed on the concrete surface, follow the mixing directions of the polymer manufacturer. Using neat material, add 5 parts silica to the mixed epoxy and blend until an even homogenous epoxy grout has developed. The consistency of the mix should be a little dryer than pourable grout but wet enough to be self-priming.
6. Place the narrowest diameter end of the cup form on the concrete surface to be tested. Pour the mixed epoxy and sand into the form at about 1-inch deep. Move the epoxy around in the form to wet out the concrete surface with the mixing tool. Compact epoxy grout and immediately fill up the balance of the form with the uncured EPC, compact again and strike off the top.
7. Allow epoxy grout to cure and become tack-free.
8. With one blow, carefully hit the hardened epoxy cup sample with the hammer to separate the cup sample from the concrete.
9. When testing a finished epoxy system for adhesion, pre-drill 3/8-inch deep into the concrete at the area to be tested. Carefully vacuum up all dust from the drilling process then follow the above steps for test placement and testing.

Types of Failure

• Cohesive concrete failure: The failure is in the concrete. Most desirable type of failure. Indicates that the epoxy is properly cured and adhering well to the substrate.
• Cohesive polymer failure: This failure is caused by not curing the epoxy long enough. The test must be redone allowing for a longer curing period.
• Adhesive failure: A separation of the polymer from the concrete surface. This failure indicates that the concrete needs additional surface preparation.

Inspection of Test Samples

• Record each type of failure and location.
• Record failure by the percentage of concrete adhesion to the epoxy grout.
• Record thickness of concrete adhering to the epoxy noting thinnest, thickness, and average thickness over the entire area.

Acceptable Standards

100% cohesive concrete failure. This is a pass or fail test!

Rejection

• Test sample that does not meet the acceptable standard may be rejected. Unless otherwise specified, the concrete surface sector rejected shall be re-cleaned and re-tested as stated above.
• In the event of rejection, the sector rejected shall be re-tested in four locations of equal square footage to verify proper surface preparation.
• Cohesive polymer failure may be re-tested without re-cleaning.
• Adhesion failure of coating or overlay. Sound the floor with hammer or chain dragging methods to determine if other areas have not adhered. Saw cut perimeter of un-adhered areas 1/4 in. deep into the concrete. Remove coating or overlay. Re-clean exposed concrete surface. Re-test as stated above. After passing the test, reapply coating or overlay. Sound coating or overlay for adhesion.

Limitation

• This test method does not provide recordable values in inch-pound units, however, it does provide a test method for the determination of surface cleanliness and polymer adhesion to the concrete.

The Most Common Epoxy Flooring Installation Problems

There are typically a handful of issues that installers most commonly see when installing a floor coating. The four most common are: Pin Holes, Bubbles, Fish Eyes, Dull finish. We are going to discuss the main reasons why these issues happen, how to try and prevent them from occurring, and what can be done to fix them when they do happen.

Problem: Pin Holes Caused by Out Gassing

Cause: Out Gassing from the concrete forms small (usually pin size) holes. These can become more prevalent when coating over porous concrete (old concrete that was opened up by aggressive shot blasting or when too much water was added during pour/concrete that was overworked).  Applying the coating while the temperature is rising also increases the potential for outgassing.

Prevention:  There are several steps you can take to try and prevent the occurrence of outgassing. Apply the coating later in the day when the temperature is falling, turn off heaters blowing warm air on the coating, and prime the surface with a low viscosity primer. Two thinner coats are always better than one thick coat.

Fix: Once it occurs, the best solution is to scrape, sand, and recoat the floor. If there are only a couple of pinholes in the floor, you may be able to spot fill them.

Problem: Bubbles in the Coating (usually larger than pinhole size)

Cause:  Air that has been entrapped in the coating that does not have time to escape. It’s typically caused by over mixing, over rolling, and/or when cold material has a higher viscosity and can hinder air release. Coatings applied in greater thicknesses can be more susceptible since it’s harder for air to escape.

Prevention:  Do not over mix or pull material into a vortex while mixing. Apply with a squeegee in both directions (overlap about 50%) and back roll in the opposite direction. These larger bubbles typically happen within the first half-hour of the coating being laid and they can be popped as they are happening.

Fix: If only a few pop up, you may be able to spot fix them and it shouldn’t be much of an issue in a basecoat.  Lightly sand down any lip that may have formed and fill the area (taking care, not to over fill). If it happens on a large scale, the only solution is recoating.

Problem: Fish Eyes / Crawling is typically a surface tension issue where the coating pulls away from itself and forms a crater.

Cause: Usually caused by concrete or prior coating being contaminated, usually with an oil or silicone. Or it can happen when applying a second coat and you miss the re-coat window.

Prevention:  The most effective way to prevent this is through proper surface preparation and to make sure all contaminated areas are clean prior to installation. If the re-coat window is missed, you’ll need to sand and tack wipe the existing coating.

Fix:  If the fish eyeing is occurring while you are applying the coating, then continue to back roll. You may be able to spot fix it after the coating hardens if the issue is isolated to a small area. If it’s widespread, the coating may have to be removed and then clean and degrease the concrete.

Problem: Dull or flat finish in urethane / Surface can also be soft.

Cause: High humidity, rain or fog is usually the main culprit. The solvents that are present in urethanes cannot escape before the system starts to cure.

Prevention:  Don’t use urethanes during these types of high humidity conditions. Do not apply urethanes if the temperature is within 10° F of the dew point. It would be better to wait until the conditions are better, even if that means missing the re-coat window.

Fix: Unfortunately, there is no easy fix for this type of issue; the dull coating will need to be recoated.

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