General Recoat Sequencing Guidelines for Our 100% Solids Epoxy Products

A Note About Cure Times

The cure times discussed below assume the epoxy, the concrete, and the surrounding air are all approximately 77°F (25°C). Cooler temperatures will slow the curing process, while warmer temperatures will accelerate it. Keep in mind that the temperature of the epoxy when you mix it and the temperature of the concrete it is being applied to are generally more important than the air temperature in determining how quickly the epoxy will cure.

Remember that these are general guidelines. The condition of the epoxy is always a better indicator than the clock. Always consult the Product Data Sheet for the specific product you are using, as individual products may have additional application or recoat requirements.

When Can the Next Coat Be Applied?

Typically, any of our 100% solids epoxy products can be applied over any of our other 100% solids epoxy products as soon as the underlying material is hard enough to walk on, regardless of whether the underlying material is being used as a primer, sealer, binder for an epoxy mortar, or coating.

Since these are our 100% solids epoxy products, there is no solvent that must evaporate before applying the next coat. Once the underlying material is hard enough to walk on without being damaged, it is generally ready to receive the next coat.

However, you should not wait more than approximately 24 hours before applying the next coat. After that point, the epoxy has cross-linked enough that it can no longer develop a strong chemical bond to itself without additional surface preparation.

If more than 24 hours has elapsed, mechanically abrade the surface, then solvent wipe it to remove dust and other contaminants before applying the next coat.

Surface Preparation Between Coats

Before applying any of our 100% solids epoxy products to concrete, the surface should be:

• Clean
• Dry
• Free of dust
• Free of dirt
• Free of oil
• Free of other contaminants

Once an epoxy coat has been applied, take care to keep its surface clean. As long as the epoxy remains free of contamination and you apply the next coat within the recommended recoat window, you should have no problem obtaining a good bond.

Do These Guidelines Apply to Epoxy Mortars?

Yes.

The same general guidelines apply when one of our 100% solids epoxy products is used as the binder for an epoxy mortar.

Once the mortar is hard enough to walk on, it is generally ready for the next step.

When Is an Epoxy Mortar Ready to Grind?

Rather than relying strictly on elapsed time, I recommend allowing the mortar to cure overnight and then performing a small test grind.

If the mortar:

• Does not excessively clog your grinding wheel or sandpaper, and
• Remains sound without peeling or tearing out,

it is generally ready for production grinding.

If you allow the mortar to cure for two or three days before grinding, it will generally clog your grinding equipment less, but it will also become somewhat more difficult to grind. Most installers eventually find the balance that works best for their equipment, working conditions, and personal preferences.

Should Crack Fillers Be Applied Over a Primer?

Typically, no.

If the crack or joint has been properly prepared, our crack fillers are normally applied directly into the prepared crack or joint without first applying a primer.

Be sure to install a properly sized bond breaker or backer rod whenever appropriate to prevent a three-sided bond. Preventing three-sided bonding allows the joint filler to accommodate significantly more movement and also helps keep the material within the joint rather than flowing into the crack below or into the underlying soil.

Roller or Notched Squeegee?

A notched squeegee is typically used only for sand-filled overlay systems.

For most applications of our 100% solids epoxy products, a quality roller is the preferred application method.

We generally recommend:

• A good-quality, shed-resistant roller cover
• A 3/8-inch nap
• A 9-inch roller

Some installers prefer an 18-inch roller. However, on many floors—especially older or uneven concrete—a 9-inch roller is often easier to control and may actually produce a more uniform application.

Mix smaller batches than you might think you can comfortably use. Larger batches generate more heat, shortening the working time of the epoxy. Lower temperatures increase working time, while higher temperatures decrease it. Adjust your batch size accordingly. Also remember that 100% solids epoxy is heavy enough that lower-quality roller covers are more likely to shed fibers into the coating.

Final Thoughts

Successful epoxy installation depends on observing the condition of the material rather than relying solely on elapsed time. Temperature, concrete condition, batch size, and application method all influence curing and working time.

By understanding these principles and following the Product Data Sheet for the specific product being used, you will achieve the best possible results with our 100% solids epoxy systems.