Waterproof Paint: Know these Before Applying

Written By Adam Paul – Waterproofing Expert

Waterproof paints are a type of paint that provides a barrier to water penetration into the substrate. Waterproof paints can withstand up to 15 PSI water pressure, and it can dry within 4-5 hours after application. It can withstand on the surface effectively for about 5-6 years. Waterproof paints are highly resistant to mold, mildew, and other bacteria and fungi that grow on the surfaces. The most used waterproof paints are Epoxy, Acrylic paints, Latex based paints (masonry paints), Silicone based paints, and Acrolein elasticized paints.

The most important properties of waterproof paints are moisture resistance, mold and mildew resistance, toxicity (VOC), thermal resistance, and scratch resistance. You should apply waterproof paint by following 7 steps in the main 3 periods of the year, which is recommended by the Aqviz experts.

The average thickness of the waterproof paint coating is 0.2-0.5 mm (0.008-0.020 in). When you apply waterproof paint, you should consider the sunlight, wind, humdity temperature, and rainfall. Waterproof paint can be used on mostly used materials such as wood, concrete, and metal, and most commonly used areas such as basements, bathrooms, and kitchens.

Waterproof paint can be damaged by higher physical impacts, exposure to harsh chemicals, extreme temperatures, UV light, and incorrect applications on the surface. You can protect waterproof paint by applying UV protective sealant, using gentle cleaning methods, avoiding harsh chemicals, extreme temperatures, and applying the paint with proper sealant and primers according to the proper method statements.

What are the Waterproofing Paints?

Waterproofing paints are a type of paint that provides a barrier to water penetration into the substrate. Waterproof paints can resist upto 15 PSI maximum water pressure and have 4-5 hours of drying time. These paints are highly resistant to mold, mildew and moisture based bacteria. The most used waterproofing paints are Epoxy, Acrylic paints, Latex based paints (masonry paints), Silicone based paints, and Acrolein elasticized paints.

Waterproofing paints are typically used in areas where moisture or water damage is a concern, such as basements, bathrooms, interior walls, and exterior walls. These paints can be applied to a variety of surfaces, such as masonry, concrete, wood, and metal.

What types of Paints are Waterproof?

The most used waterproof paint types are Epoxy, Acrylic paints, Latex based paints (masonry paints), Silicone based paints, and Acrolein elasticized paints. These can be used in prevent water leaking in various areas.

1. Acrylic waterproof paint: Acrylic waterproof paint is a water based paint. It is an It can and a great option for waterproofing walls. Acrylic paint will withstand 10 – 15 years It’s easy to apply and dries quickly.
2. Epoxy waterproof paint: Epoxy waterproof paint is a durable, chemical resistant, smooth finished and highly waterproof paint. It can be used in higher humidity areas as well as higher foot traffic areas as a coating on the floor.
3. Silicone waterproof paint: Silicone waterproof paints are typically used on roofs due to its excellent waterproofing properties. It’s also resistant to UV rays and high temperatures.
4. Elastomeric waterproof paint: Elastomeric waterproof paint is incredibly durable and can stretch to cover cracks and small holes, providing a waterproof seal. It’s often used on exterior walls and roofs.
5. Latex waterproof paint: Latex waterproof paint is a versatile type of paint that can be used on a variety of surfaces. It’s water-based and provides a strong waterproof seal.

What are the Properties of Waterproof Paint?

The main properties of waterproof paints are moisture resistance, mold and mildew resistance, toxicity, thermal resistance, and scratch resistance of the paint.

Moisture Resistant

Waterproof paint is a moisture-resistant paint. When the waterproof paint dries, it forms a water-tight barrier that does not let water to pass. Applying waterproofing paint can control the interior humidity level, and prevent the wood from rotting, material deterioration, and paint peeling on the walls. Hence, it can be used in higher moisture areas such as bathrooms, basements, and kitchens for interior and exterior walls.

Mold and Mildew Resistant

Waterproof paints are resistant to mold and mildew growth on the paint surface. It prevents growing mold types such as Aspergillus, Cladosporium, Penicillium, and Stachybotrys chartarum and types of fungus on the surface that cause significant damage to the structure. Applying waterproof paint on the surface can prevent mold and mildew damage, such as structural damage and health hazards. Hence, it can be used in areas with higher humidity that cause higher mold and mildew growth.

Toxocity

Not, all waterproof paints are toxic. The most toxic waterproofing paint is Acrolein elasticized paint, which is a highly toxic material when it is mixed with acrylic paint, although it produces a waterproof layer. The toxicity of the waterproof paint is measured by the VOC ( Volatile Organic Compounds). The U.S. Environmental Protection Agency (EPA) recommends that for indoor paints, the VOC level should not exceed 250 grams per liter (g/l) for flat paints and 380 g/l for other paints, including glossy or semi-glossy finishes.

How to Apply a Waterproof Paint?

You should follow these 7 steps when applying waterproofing paint on the surface. This step-by-step guide is prepared by the Aqviz experts that we on our sites.

1. Inspect the surface: First, you should inspect the surface before applying the waterproof paint. You should check for cracks, hairline fractures, damp patches, efflorescence, mold growth, loose plaster, and peeling paint. This helps to identify moisture sources and weak zones that can cause coating failure.
2. Clean the surface: Second, you should clean the surface by removing dust, oil stains, algae, laitance, and loose particles using wire brushing, water washing, or pressure cleaning. This helps to improve paint adhesion and surface bonding.
3. Repair surface defects: Third, you should repair cracks, holes, and honeycombs using polymer-modified mortar or crack fillers. This helps to create a uniform and sound substrate because waterproof paint cannot bridge open defects.
4. Dry the surface: Fourth, you should allow the surface to dry completely if internal moisture is present. This helps to prevent blistering, bubbling, and peeling after application.
5. Apply primer: Fifth, you should apply a compatible primer or bonding coat as recommended by the manufacturer. This helps to regulate surface porosity and strengthen paint adhesion.
6. Apply waterproof paint: Sixth, you should apply the waterproof paint evenly using a brush, roller, or spray in the recommended number of coats. This helps to form a continuous water-resistant barrier.
7. Allow curing: Finally, you should allow adequate curing time before exposing the surface to water or weather. This helps to achieve full waterproofing performance and coating durability.

When Should You Apply Waterproof Paint?

When you apply waterproof pain you should apply it in these 3 main periods of the year.

1. Late spring: You should apply waterproof paint in late spring because temperatures stay stable between 15-25 °C (59-77 °F) and humidity levels remain moderate. This allows the coating to cure evenly and bond strongly without moisture entrapment.
2. Early summer: You should apply waterproof paint in early summer if rainfall is low and surfaces stay dry throughout the day. This period helps achieve faster curing and reduces the risk of blistering caused by overnight condensation.
3. Early fall: You should apply waterproof paint in early fall because daytime temperatures remain warm while extreme heat drops. This prevents rapid surface drying, cracking, and poor film formation before winter moisture exposure.

From our Aqviz projects, coating failures increase by more than 35% when waterproof paint is applied during rainy seasons or when temperatures fall below 10 °C (50 °F).

What is the Thickness of the Waterproof Paint Coating?

The average thickness of the waterproof paint coating is 200–500 microns (0.2–0.5 mm | 0.008–0.020 in). Thickness can be achieved in 2-3 coats when applying a waterproof membrane on the surface. The thickness of the waterproof paint depends on the substrate condition and paint formulation.

If the waterproof paint thickness is increased beyond this range, it causes reduced breathability, delayed curing, surface cracking, blister formation, and weak intercoat bonding.

If the waterproof paint thickness is decreased below the recommended range, it causes poor water resistance, pinhole formation, early coating erosion, reduced UV protection, and a shortened service life.

What are the Environmental Conditions for Waterproof Paint?

These are the 5 key environmental conditions you should pay attention for waterproof paint application based on our field experience.

• Sunlight: You should control direct sunlight exposure because intense UV and surface heat can cause rapid drying, poor film formation, and surface cracking.
• Wind: You should avoid strong wind conditions because wind accelerates evaporation, causes uneven thickness, and introduces dust contamination onto the wet coating.
• Humidity: You should maintain relative humidity below 75% because high moisture levels delay curing and increase the risk of blistering and whitening.
• Temperature: You should apply waterproof paint when ambient and surface temperatures remain between 10-35 °C (50-95 °F) because extreme cold slows curing and excessive heat weakens bonding.
• Rainfall: You should ensure a rain-free period before and after application because early water contact washes out binders and damages the uncured coating.

From our Aqviz projects, controlling these five conditions imp

How Long Does a Waterproof Paint Last?

In practically waterproof paint can last 3-6 years. The durability of waterproofing depends on various factors such as the quality of the paint, the surface it is applied to, and the environmental conditions it is exposed to. The durability of waterproof paint can increase with the proper protection and maintenance of the paint.

Waterproof paint can shorten due to exposure to harsh weather conditions, UV radiation, and heavy foot traffic. Damaged waterproof paint tends to leak water into the substrate and increase the water damage.

Where Can You Use Waterproof Paint?

Waterproof paints can mainly be used on materials like wood, concrete, metal, and building structures such as basements, bathrooms and kitchens.

Waterproof paint on wood

Waterproof paint can be used on wood. Applying waterproof paint on the wood is an effective way to protect the wood from problems such as wood rotting, warping, cracking, growing mold, and mildew. It helps to create a barrier that water and moisture cannot penetrate. Some waterproof paints also offer protection against UV rays, which can cause wood to fade and degrade over time.

Wood can be damaged easily by water, moisture, and other environmental factors. When it is exposed to higher moisture over time, wood can warp, crack, rot, or grow mold and mildew. These problems not only affect the appearance of the wood but also its structural integrity. For example, wooden structures or furniture can become unstable and unsafe if they are significantly damaged by water and moisture.

Waterproof paint on concrete

Waterproof paint can be applied on the concrete surface to prevent water damage on the concrete. Applying waterproof paint is an effective way to prevent these problems, such as efflorescence, spalling, and mold growth on the concrete surface.

Concrete is a highly durable material, but it is not resist to water and moisture damage. When concrete is exposed to water over time, it can lead to various problems such as efflorescence, spalling, mold and mildew growth, and even structural damage. Efflorescence is a white powdery substance that appears on the surface of concrete when water seeps through it and brings salts to the surface. Spalling, on the other hand, is a condition where the surface of the concrete starts to flake or peel off due to water penetration.

Waterproof paint on basements

Applying waterproofing paint in the basement can solve the primary water-related problems in basements, such as dampness, leaks, condensation, and flooding. Waterproof paints can seal the cracks and pores in the concrete. It helps to prevent water and moisture seepage, mold and mildew growth, paint peeling, rotting the materials, deterioration the materials, and structural damages in the basement.

You can apply waterproof paint on the basement interior walls and exterior walls for higher protection of water.

Related: Basement Waterproofing: What You Should Know?

Waterproof paints on bathrooms

Waterproof paint can be applied for bathroom waterproofing to solve many water related problems such as preventing mold and mildew on the bathroom walls, wall damage, efflorescences, stain marks on the walls, and paint peeling on the walls.

The bathroom is a highly water consuming area, and it always consists of higher humidity. Significantly higher humidity increases the mold and mildew growth on the walls. Also, higher water consumption causes a leak of water into the building structure. In order to prevent these problems, you should apply waterproof paint on the bathroom walls.

How to Protect Waterproof Paint?

Waterproof paint can be protected by the following 10 methods.

1. Apply a UV-protective sealant.
2. Use gentle cleaning methods.
3. Avoid harsh chemicals.
4. Maintain a consistent temperature.
5. Keep the surface dry to prevent mold and mildew.
6. Apply the paint correctly.
7. Use a primer before painting.
8. Protect from physical impacts.
9. Regularly inspect and touch up as needed.
10. Avoid high-pressure washing.

How to Damage Waterproof Paint?

Waterproof paint can be damaged in these 6 ways.

1. Higher physical impact on the waterproof paint: Waterproof paint can be damaged by the higher physical impact, such as scratches, dents, or holes, due to moving furniture, accidents, or any sharp objects coming into contact with the painted surface.
2. Exposure of waterproof paint to harsh chemicals: Waterproof paint can be deteriorated by harsh chemicals such as bleach, ammonia, and other cleaning and corrosive substances.
3. High-pressure washing the waterproof paint: Using a high-pressure washer on a painted surface can cause the paint to chip or peel off.
4. Exposure to waterproof paint to extreme temperatures: Waterproof paint can also be damaged by extreme temperature changes. Very high temperatures can cause the paint to crack and peel, while very low temperatures can make it brittle.
5. Exposure to waterproof paint to UV light: Waterproof paint can be damaged by exposing the paint to direct sunlight, which can fade the color of the paint over time and make it less resistant to water.
6. Apply waterproof paint incorrectly: Waterproof paint can be damaged If the paint is not applied correctly, it can lead to problems down the line. This includes not preparing the surface properly, not using the correct primer, or applying the paint too thinly or too thickly.