Ultimate Guide for Epoxy Waterproofing on Concrete

Written By Adam Paul - Waterproofing Expert

Using Epoxy waterproofing on concrete is a successful waterproofing method to protect the concrete from water damage, mold growth, and surface deterioration over time. In order to have efficient epoxy waterproofing on concrete you should install it properly. 

So Aqviz we, highly recommend you know these things when you waterproof the concrete using epoxy. Epoxy is a highly water resistant material but is not breathable. It completely blocks all the moisture in the concrete. The thickness of the epoxy waterproofing layer is between 1-2mm and it will take 24-72 hours for complete curing. You should have a proper concrete substrate to adhere the epoxy with substrate properly and you can't directly apply it on the concrete surface. 

As well as you can use epoxy on concrete cracks after repairing them. You can use epoxy on both older and newer concrete surfaces with proper surface preparation and curing. You should not use epoxy on below grade structures. If you use epoxy on higher foot traffic areas you will need a thicker layer. The cost of epoxy waterproofing is $3 to $12 per square foot ($32 to $130 per square meter). And also you should know the causes of the epoxy damage in the concrete surface.

Aqviz's expert team has prepared this guide including all the important information when you waterproof the concrete using epoxy. So we highly recommend you follow the information mentioned below and waterproof the concrete properly using epoxy. 

Does Epoxy Waterproof Concrete?

Yes, epoxy waterproofs the concrete effectively. Epoxy forms a seamless, non-porous coating on the concrete substrate that acts as a strong barrier against water penetration. It prevents moisture from seeping into the concrete, protecting it from water damage, mold growth, and surface deterioration over time. 

However, while epoxy is highly water-resistant, it is not always a long-term waterproofing solution for areas with significant hydrostatic pressure (water pressure from underground sources). In such cases, we often reinforce the epoxy layer with additional waterproofing systems, such as primers, moisture-mitigating sealers, or drainage solutions.

Is Epoxy Waterproofing Breathable?

No, epoxy waterproofing is not breathable. Once cured, epoxy forms a dense, impermeable layer that completely blocks water and vapor from passing through. This makes it an excellent choice for surfaces that need total moisture protection.

However, because it is non-breathable, epoxy may trap moisture within concrete if the substrate is already damp or if there is underlying moisture pressure. This can lead to bubbling, peeling, or delamination over time. To prevent these issues, Aqviz experts always recommend applying an appropriate moisture barrier or testing for moisture content before applying epoxy on the concrete.

How Thick Should an Epoxy Waterproofing Layer Be on Concrete?

The average thickness of an epoxy waterproofing layer on concrete ranges between 1mm to 3mm (40 to 120 mils), depending on the application and exposure conditions.

So let’s, see what happens when the thickness is less than 1mm and more than 3mm.

If the epoxy layer is too thin (<1mm): The coating may not fully seal the surface, reducing its waterproofing effectiveness. Thin layers are more prone to wear, cracks, and failure under heavy traffic or constant water exposure.

If the epoxy layer is too thick (>3mm): Excessive thickness can lead to improper curing, making the epoxy brittle or prone to cracking. In some cases, thick applications may trap air bubbles or moisture underneath, compromising adhesion and durability.

Our experts highly recommend using multiple epoxy layers of epoxy on heavy duty areas such as garages, parking, and industrial settings. This ensures maximum durability without risking structural issues.

How Long Will It Take to Cure Epoxy Waterproofing on Concrete?

Epoxy waterproofing on concrete typically takes 24 to 72 hours to cure under normal conditions. However, full chemical curing (maximum hardness and waterproofing performance) can take 7 to 14 days depending on the type of epoxy used.

So, what factors affect curing time?

• Temperature: Higher temperatures (above 25°C or 77°F) speed up curing, while colder temperatures (below 15°C or 59°F) slow it down significantly.
• Humidity levels: High humidity can interfere with proper curing, especially if moisture gets trapped, leading to improper bonding.
• Ventilation: Good airflow helps speed up curing, whereas poor ventilation can prolong drying time.
• Layer thickness: Thicker epoxy layers take longer to cure because heat buildup from curing reactions needs to dissipate properly.
• Type of Epoxy: Fast-curing formulas (accelerated epoxy systems) can be ready in 12 to 24 hours, while industrial-grade waterproofing epoxies may require several days.

We always recommend waiting at least 48 hours before light foot traffic and 7 days before exposing the surface to heavy water or mechanical stress.

How Does Epoxy Penetrate and Bond with Concrete Surfaces?

Epoxy bonds to concrete through a combination of mechanical adhesion and chemical interaction at the molecular level. Epoxy bonds with concrete in the main 4 steps such as penetration into pores, chemical bonding, cross linking, and thermal expansion.

• Penetration into pores: Concrete is naturally porous. It contains tiny capillaries and air pockets. When epoxy is applied, its low-viscosity components penetrate these pores, anchoring itself within the surface.
• Chemical bonding: Epoxy contains reactive polymers that chemically interact with minerals in the concrete, forming covalent and hydrogen bonds. This strengthens adhesion and prevents delamination.
• Cross linking (Curing Process): As the epoxy cures, its molecular chains form a dense, three-dimensional network, locking onto the concrete and creating a rigid, waterproof barrier.
• Thermal expansion compatibility: Once cured, epoxy expands and contracts with the concrete, preventing cracks and separation under temperature changes.

In order to have a better and stronger epoxy bonding with concrete layer should have a proper thickness. 

How to Prepare a Concrete Surface Before Applying Epoxy Waterproofing?

Before applying epoxy waterproofing, a layer should be prepared like this.

1. Clean the concrete surface: First, you should clean the concrete surface by removing dust, grease, oil, and debris using a degreaser or detergent.
2. Prepare the concrete surface: Then fill any crack or void on the surface. Use epoxy based compound for better results.
3. Apply the primer on the concrete: Apply the primer on the concrete surface for better adhesion with the substrate 
4. Mix the epoxy: Mix the epoxy resin and hardener uniformly with the recommended proportions.
5. Apply the Epoxy on the concrete surface: Apply the epoxy waterproofing on the concrete surface using a roller or brush. Maintain the epoxy thickness 1mm-2mm uniformly.
6. Allow epoxy for curing: Leave the epoxy layer for curing as per the manufacturer's guidelines.
7. Apply the second coating if needed: Then apply the second epoxy layer on the previous one, if the manufacturer recommends it.

Read more about: How to Seal Concrete with Epoxy?

Can Epoxy Waterproofing Be Applied Over Cracks in Concrete?

Yes, but only after proper crack repair. Epoxy waterproofing alone is not designed to bridge active cracks or structural gaps. Before application, we must fill and seal cracks using an epoxy injection, polyurethane sealant, or an epoxy patching compound. If cracks are left untreated, water can still penetrate through them, compromising the waterproofing layer.

Can You Directly Apply Epoxy Waterproofing on Concrete?

No, you can't apply Epoxy waterproofing on concrete. You should prepare the surface for epoxy waterproofing. Because concrete contains dust, oils, and moisture that can prevent epoxy from bonding effectively. If applied directly without cleaning, grinding, or priming, the epoxy may fail to adhere, leading to peeling or delamination over time. To ensure a strong bond, we always clean, repair, and profile the surface before application.

Can Epoxy Waterproofing Be Used on Both New and Old Concrete?

Yes, you can we highly recommend you to follow the below.

• New concrete: New concrete must cure fully for at least 28 days before applying epoxy. If you apply epoxy too early can lead to adhesion failure due to moisture trapped within the slab.
• Old concrete: Old concrete requires thorough cleaning, crack repairs, and surface profiling before application. Becuase old surfaces often have contaminants or coatings that must be removed for proper bonding.

If you have a problem regarding new or old concrete surfaces contact us for more information. Aqviz agent will support you to do this DIY.

Can Epoxy Waterproofing Be Used for Below-Grade Structures?

No, you can't use epoxy for below grade waterproofing because epoxy is not designed to withstand extreme hydrostatic pressure found in below-grade structures like basements and foundations. Over time, pressure from underground water can push against the epoxy, leading to cracking, peeling, or water infiltration.

For below-grade waterproofing, Aqviz experts highly recommend you to use epoxy with additional waterproofing systems, such as:

• Cementitious coatings (for extra water resistance)
• Drainage systems (to relieve hydrostatic pressure)
• Flexible waterproofing membranes (to accommodate structural movement)

Can Epoxy Waterproofing Be Used for Heavy Foot Traffic Areas?

Yes, epoxy waterproofing is highly suitable for heavy foot traffic areas. Epoxy creates a durable, abrasion-resistant, and impact-resistant surface that can withstand continuous use. It is commonly applied in garages, warehouses, commercial spaces, and industrial floors where durability is essential.

To enhance performance in high-traffic zones, we often:

• Increase the epoxy thickness (2mm–5mm) to prevent wear.
• Use slip-resistant additives for better traction.
• Apply a polyurethane or high-performance topcoat for added strength and UV resistance.

Properly installed and maintained epoxy waterproofing offers a long-lasting, durable surface that resists wear from foot traffic and even light vehicle movement.

What Is the Cost of Epoxy Waterproofing on Concrete?

The cost of epoxy waterproofing is $3 to $12 per square foot ($32 to $130 per square meter). But the epoxy waterproofing cost varies depending on the quality of materials, application method, and surface preparation requirements. 

What are the Common Causes of Epoxy Waterproofing Failure on Concrete?

These are the common 7 causes of epoxy waterproofing failure on concrete

1. Poor surface preparation: Epoxy may not bond well on poor concrete surfaces. It leads to peeling, blistering, or delamination over time.
2. Moisture issues in concrete: If the concrete has high moisture content or rising dampness, trapped water vapor can push the epoxy layer upward, causing bubbling or adhesion failure.
3. Incorrect mixing of epoxy components: Improper epoxy mixing leads to soft spots, uneven curing, and weak waterproofing performance. 
4. Applying epoxy on an uncured or weak concrete base: If epoxy is applied too soon, moisture from the curing concrete can cause blistering, bubbling, or poor bonding.
5. Temperature and humidity issues: High humidity (>80%) can cause condensation, leading to poor adhesion. Cold temperatures (<50°F or 10°C) slow down curing, making the epoxy brittle or incomplete.
6. Applying epoxy too thick or too thin: 
7. Exposure to harsh chemicals like acids or solvents