What Happens If Flex Seal Gets Wet Before It Cures

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When it comes to sealing and waterproofing projects, Flex Seal is a popular choice for its ease of application and effectiveness. However, what happens if Flex Seal gets wet before it cures? In this article, we’ll explore the impact of moisture exposure on the curing process, adhesion, waterproofing performance, and long-term durability of Flex Seal.

Impact on Curing Process

Flex Seal is a liquid rubber sealant that cures when exposed to air. However, if it gets wet before it cures, the water can interfere with the curing process and prevent the sealant from forming a strong bond.

In general, the more water that comes into contact with Flex Seal before it cures, the less effective the sealant will be. For example, if you apply Flex Seal to a wet surface, the water will prevent the sealant from adhering to the surface properly.

This can lead to the sealant peeling or flaking off over time.

Water Exposure

The type of water exposure can also affect the curing process of Flex Seal. For example, if Flex Seal is exposed to salt water, the salt can corrode the sealant and weaken its bond. Similarly, if Flex Seal is exposed to hot water, the heat can cause the sealant to break down and lose its effectiveness.

Surface Adhesion

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Flex Seal’s impressive adhesive capabilities extend to damp surfaces, offering a reliable bond even in challenging conditions. However, applying Flex Seal to wet surfaces may compromise its adhesion properties, potentially leading to peeling or detachment.

Consequences of Applying Flex Seal to Wet Surfaces

Applying Flex Seal to wet surfaces can result in the following consequences:

  • Reduced Adhesion Strength:Water can act as a barrier between Flex Seal and the surface, weakening the adhesive bond and reducing its effectiveness.
  • Peeling or Detachment:If the adhesion is compromised, Flex Seal may peel or detach from the surface, leaving the area unprotected and exposed.
  • Compromised Seal:A weakened bond can allow moisture or air to penetrate the seal, reducing its ability to prevent leaks or protect the surface.

Waterproofing Performance

What happens if flex seal gets wet before it cures

When Flex Seal is applied and exposed to moisture before it cures completely, its waterproofing capabilities can be significantly compromised.

The uncured Flex Seal forms a temporary barrier that prevents water penetration initially. However, as the water remains in contact with the uncured sealant, it can penetrate through the barrier and reach the underlying surface.

Specific Scenarios

  • Leaks in Roofs and Gutters:If Flex Seal is applied to a roof or gutter and it rains before the sealant cures, water can seep through the uncured areas and cause leaks.
  • Reduced Protection for Boats and Vehicles:When Flex Seal is used to seal boats or vehicles, exposure to moisture before curing can reduce its effectiveness in protecting against water damage. The water can penetrate the uncured sealant and reach the interior of the boat or vehicle, leading to corrosion or other issues.

Long-Term Durability

Extended exposure to moisture can have detrimental effects on the long-term durability of Flex Seal. Water can penetrate the sealant’s surface, weakening its bond with the underlying substrate and causing premature deterioration.

The presence of moisture can also accelerate the breakdown of the sealant’s chemical structure, leading to cracking, peeling, and loss of adhesion. In severe cases, prolonged moisture exposure can compromise the integrity of the sealed surface, resulting in leaks or structural damage.

Impact on Sealant’s Bond

Water can weaken the bond between Flex Seal and the surface it is applied to. As water seeps into the sealant, it can disrupt the chemical bonds that hold the sealant in place. This weakening of the bond can lead to the sealant peeling or flaking off, compromising the seal and allowing water to penetrate the protected surface.

Premature Deterioration

Moisture can also accelerate the deterioration of Flex Seal. The sealant’s chemical structure can break down when exposed to water, leading to cracking, peeling, and loss of adhesion. This premature deterioration can significantly shorten the lifespan of the sealant and compromise its ability to protect the underlying surface from water damage.

Recommended Applications: What Happens If Flex Seal Gets Wet Before It Cures

Ensuring a dry surface before applying Flex Seal is crucial for optimal performance and durability. Moisture can hinder adhesion and compromise the integrity of the seal.

To prepare surfaces effectively, follow these steps:

Surface Preparation

  • Clean the surface thoroughly to remove dirt, grease, and debris.
  • Allow the surface to dry completely before applying Flex Seal.
  • If the surface is porous, consider applying a primer to enhance adhesion.
  • Protect the surrounding area from overspray or spills.

Repair and Maintenance

What happens if flex seal gets wet before it cures

Flex Seal exposed to moisture before curing may require repairs. Proper techniques are crucial to restore its effectiveness and longevity.

To repair compromised Flex Seal, follow these steps:

Cleaning and Preparation, What happens if flex seal gets wet before it cures

  1. Remove any excess moisture or debris from the affected area.
  2. Allow the area to dry completely.
  3. Sand the damaged area lightly to create a rough surface for better adhesion.


  • Apply a thin layer of Flex Seal to the prepared area.
  • Allow the first layer to dry partially, until it becomes tacky.
  • Apply a second layer of Flex Seal and smooth it out.
  • Allow the repaired area to cure completely according to the manufacturer’s instructions.