An Epoxy Floor Coating Problem Solving Guide

An Epoxy Floor Coating Problem Solving Guide

Posted by Bryon Hendricks on Aug 2nd 2018

This posts discusses 

Color Differential

Fish Eye

Milky or Cloudy Coatings

Orange Peel

Peeling or Delamination

Moisture Vapor

Delamination between Coats


Product Settling

Not Drying/Slow Drying

Stains/Tire Marks

Uneven Flake/Chip Application


Color Differential:


Difference in color or shading of topcoat.


Re-touching after 15 minutes: Color float issues arise when a pigmented epoxy has been applied and is re-touched or rolled again after setting for 15 minutes or longer. Different shades in the color may result.

Using Different Batch Numbers: Coloring can vary from batch to batch. Different batches used on the same project can result in color variances.

Improper mix ratios: Adding color in the field without using the same base batch and the same amount of color pigment in each mix can result in color variations.


Back roll the entire area always using an 18”, woven, shed-resistant, 3/8” nap roller. Always try to go across the entire area from side-to-side.

When possible, recoats should always be completed with the same coating batch.


If material needs to be re-touched or rolled for any reason, it needs to be done within 10 minutes of application.

If batches are different, blend color into resin side and box all pigments prior to adding activator.

Fish Eye:


Fish eyes are round separations or indentions in the coating finish. They look like water and oil separating.


Oil/Grease Contaminants: This can cause the epoxy to work improperly ad fish eyes to appear.

Silicone: Contamination from silicone can also cause fish eyes to appear.


Oil/Grease: First start by degreasing the floor by solvent cleaning or using a degreasing detergent. This will prevent spreading of oils and greases from the sanding process. Second, sand, screen, grind the surface to prepare it for another coating. Re-install the finish coat to a newly degreased, sanded, and clean floor.


Degrease entire surface prior to any grinding or sanding. If oils and grease cannot be removed entirely, use a suitable oil-stop primer. In between coats clean with solvents prior to succeeding coats.

Milky or Cloudy Coatings:


A milky or cloudy appearance in wet or cured coating.


Moisture: Moisture in the concrete or high humidity can cause moisture to be present on the surface when the material is being applied or before it is fully cured. This can result in a milky or greasy film.This is sometimes referred to as “amine” or “blush”.

Thick application: A milky or cloudy appearance can result from product being applied too thick. It’s usually more noticeable in the clear coatings.


For moisture, remove effected area by mechanical diamond grinding. Monitor humidity levels and reapply coating with the Product Data Sheets recommendations.

If greasy, or damp wipe surface with Denatured Alcohol.


Moisture: Test the area using a calcium Chloride Kit or at minimum, use the black plastic test.

Thick Application: Follow Product Data Sheet for mil thickness recommendations. Use mil squeegee or mil roller gauges to assure proper application.

Orange Peel:


A stipple appearance to the final coat.


Cold substrate or cold materials: This will prevent the product from leveling out causing and “Orange Peel” appearance.

Hot Substrate/Materials: This can cause the product to cure too rapidly which prevents the product from leveling out.


Screen, sand, or grind the surface dull. Remove all debris and dust by vacuum. Solvent wipe and reapply the topcoat per the Product Data Sheet and coating instructions.

Hot and Cold Substrate/Materials: Substrate should be above 60 degrees and materials should be at 70 – 75 degrees. If thinning is desired, use up to 5% Acetone mixed within the coating.

Peeling or Delamination:


The epoxy is peeling or “letting go” from either the concrete or between layers of coatings.

Delamination from substrate:


Improper Cleaning: The epoxy will not adhere to dirt, grease, or other contaminants.

No Primer Used: When priming is skipped, delamination may occur.

Moisture Vapor: Water vapor penetrating up through the substrate can cause peeling or delamination. After removing the problem areas, you may notice the concrete being dark from being damp.


Improper Cleaning: The coating must be removed by grinding or blasting. Re-apply the epoxy after proper preparation.

No Primer Used: The coating must be removed by grinding or blasting. Install primer per manufacturers instructions after proper preparation.

Moisture Vapor:


Remove Coating by grinding or blasting. Measure moisture level: consult product data sheet and/or manufacturer before reapplying.


Improper Cleaning: Properly clean the substrate and provide a suitable profile by mechanical grinding or shot blasting.

No Primer: Use a suitable primer or prepare a primer following directions.

Moisture Vapor Transmission:

Substrates should have a properly installed and effective vapor barrier if in contact with the ground.

Always perform a calcium chloride test prior to installation. Test results should be no more than 4 pounds per 1000 square feet per 24 hours.

Approved primer systems should be used on readings that are higher and/or mitigate the moisture levels.

Delamination Between Coats:


Beyond recoat window: Coating was applied beyond the recommended time for recoating.

Surface contaminants: Surface was contaminated by water, humidity, oil, dust, or grease.

Improper mixing methods: Coating was not mixed at proper ratios or for 3 minutes minimum.


Beyond recoat window: Remove all loose or un-bonded coating. Screen, sand, or grind surface. Vacuum clean and wipe floor with denatured alcohol. Re-apply epoxy coating following TDS.

Surface Contamination: Remove all loose or un-bonded coating. Make sure surface is clean, dry, and free of contaminants prior to coating. Floor may need to be degreased, sanded, and wiped with denatured alcohol. Re-apply epoxy coating following TDS.

Improper mixing: Remove loose, peeling, or un-cured material. Screen, sand, or grind the coating. Solvent wipe the surface with denatured alcohol and re-apply coating following TDS.


Each coat needs to be applied within 24 hours. Check substrate carefully before applying coating, remove any contamination prior to coating. Mix all materials per the manufacturer’s instructions.



Pinholes in the coating appear as small blisters or bubbles. After the blisters pop, they leave a round crater and the pinhole can be seen through the transparent film.


Outgassing: Air escapes from the porous substrate and becomes trapped in the coating.

Temperature/Humidity: If conditions are too hot or humid, it can result in rapid drying that causes air entrapment in the coating.

Air Movement: Air movement from fans, door vents blowing directly on the surface may cause flash drying which causes bubbles.

Sunlight: Direct sunlight can cause the product to tack up before necessary air releases has occurred, which results in bubbles.

Mixing: Mixing at too high of a speed entraps air, resulting in bubbles.

Surface Prep: Extreme/aggressive shot blasting or grinding opens the pores in the concrete causing air to be trapped when the coating is applied resulting in bubbles.


Screen, Sand, or grind the problem areas dull. Vacuum dust and debris. Fill large craters with epoxy patch material. Sand patched areas and vacuum. Reapply coating at recommended rate and follow directions.


Outgassing: Use a primer system on all porous concrete. Follow directions for mixing and using primer. Spike rollers can be used if bubbles appear but may not completely remove them.

Air Movement: Eliminate any source of direct air blowing onto the surface.

Temperature and Humidity: Follow all direction to assure you are within the products recommended ranges.

Sunlight: Avoid direct sunlight when applying.

Mixing: Always use a jiffy mixer and medium to slow speeds. If air bubbles are present in coating. Allow to sit briefly before pouring onto floor.

Roller Covers: Always follow recommended nap and type of cover. Woven, Shed-Resistant rollers are recommended.

Surface Prep: Avoid aggressive shot blasting and grinding. Be sure to generate the required profile from the coatings manufacturer.

Product Settling/Frozen/Set-Up/Over Heated


Solid material Settles to the bottom of the container. This typically happens in pigmented/colored product.

Water-Based and Water-Born materials are subject to freezing conditions.

Old or outdated material or previously opened material may set up or partially set up in the container.

Materials heated artificially or kept in a hot trailer can exceed the manufacturers temperature requirements and may also break down the material resulting in a non-curing product.


Settling can occur by simply setting on the shelf or vibration though transport.

Freezing can occur during transit or stored in a non-heated area like a trailer or warehouse during winter months.

Old/Outdated Material can occur due to sitting on the shelf of your supplier or in your warehouse/trailer for longer than the manufactured product is designed.

Artificially Heated/Over Heated materials occur when they are subject to warming for cold weather use but get over-heated and break down the structure of the product.


If product appears to be settled, frozen, set-up, too thick, or too thin DON’T MIX and DON’T USE! If you use these materials you will likely not be reimbursed. 

Not Drying / Slow Drying


The epoxy does not fully cure or remains soft/tacky 24 hours after application.


Improper mix ratios, improper mixing methods, cold ambient temperatures, improper application (Thickness).


Remove the uncured coating down to the clean substrate by using solvent, scraping or mechanical grinding. Follow all chemical safety directions.

Reapply the epoxy coating per Product Data Sheet.

Never apply epoxy over uncured material.


Improper Mix Ratios: Always read and follow the printed information on the product containers or the PDS. Use buckets that have pre-printed measuring guides to assure proper mix ratios.

Improper Mixing Methods: Always mix the base side first thoroughly. Then combine with the activator. Always mix for 3 minutes using a jiffy mixer at slow to medium speed. Never use a drywall mixer. Never flip the bucket upside down on the floor to drain. This could result in sticky spots.

Cold Material/Cold Ambient Temperature/Cold Surface Temperature: Bring material to room temperature. Cool or cold temperatures will slow curing time and prevent vapor from escaping allowing blisters. Bring room and floor up to temperature 2 days prior to coating and 2 days after cure. Floor surface must be a minimum of 60 degrees from 2 days prior to 2 days after coating installation.

Stains / Tire Marks


Tire Marks: Marks left behind from vehicles.

Chemical Spills: Contamination left from spilling products on the surface.


Chemicals or Spills: Epoxies take approximately 7 days to fully cure. It is important to allow a minimum of 24 hours for foot traffic and at least 2 full days for forklift traffic or heavy loads.

Tire Marks: Due to the tire being manufactured with plasticizers, which improve cold weather traction, they tend to leach this plasticizer on to the epoxy floors when tires are warm or hot from driving. This chemical reaction between the tires and epoxy floors are sometimes unavoidable. To help prevent this, consider placing a rubber mat at the location where tire will be on a constant basis.

In some cases, a higher cost floor coating material are made to prevent this from happening.

Uneven Flake / Chip Application


Flakes that are broadcasted evenly are extremely important in the look of the overall project.

Always present the client a sample board to view the approximate amount of chips that will be used in their project.


Not taking the proper time to allow for even distribution of the flakes.

Crushing the flakes in your hand as you broadcast them.

Using the flake particles that have settled to the bottom of the container or using reclaimed chips from previous jobs.


Screen, sand, or grind the floor dull. Vacuum the debris from sanding and reapply the epoxy per directions and reapply the flakes.


Use a small bucket when carrying the flakes out onto the floor area. Do not crush flakes when grabbing. Loosely grab and throw the flakes high into the air over the epoxy floor. Gradually move around the entire area, broadcasting flakes instead of standing in one area and throwing too far.

Yellowing / Ambering


The epoxy has developed a yellow or amber hue. This will affect both clear and pigmented epoxies.


Sunlight: Epoxies, when exposed to sunlight- direct or partial, will amber or yellow over time.


Remove any dirt, grease, or oil by cleaning with appropriate cleaning agent.Screen, sand, or grind the surface dull. Vacuum clean and reapply coating per TDS.


When using a decorative vinyl flake system, use a full flake system. Remember to apply a UV stable, clear, urethane top coat. Vinyl flakes are not UV stable.

When using a solid color, use a UV stable, clear, urethane topcoat. This will prevent yellowing entirely but will hinder it. You may also wish to use a colored urethane top coat.