Leak Seal vs. Flex Seal Key Differences and Which Is Better

Leak Seal vs. Flex Seal

Your RV is susceptible to forming cracks, holes, and gaps over time. It happens due to material deterioration and degradation.

Holes and cracks can cause many problems for campers. If you notice any gaps or cracks in your vehicle, you must take measures to seal them to avoid any leakage. 

Leaky roofs, toilets, and pipes need a quick fix. But, unfortunately, you can’t always take your camper to a professional to have the leaks repaired when you’re on the road.

If you’re stuck in this situation, you need to seal the problematic cracks immediately. First, you’d require liquid sealants as they are a handy and effective solution. But there are plenty of sealants available.

The most widely used are leak seal and flex seal. But which one is better, and what are the key differences?

Leak Seal vs Flex Seal

Leak seal and flex seal are liquid rubber sealants that you can use to immediately seal any gaps, cracks, and holes in your RV’s doors, windows, roof, or other parts.

These popular sealants work equally well. But you must learn about their key differences to know how you should use them in your RV. 

Leak Seal

A Leak Seal is an effective solution for sealing cuts, leaks, and breaks as it forms a rubberized protective coating. This sealant is 100% water-resistant and has a semi-glossy finish.

In addition, it can adhere to every type of surface, which allows you to fix medium to small-sized holes and cracks. However, it isn’t suitable for larger cracks.

You can use the rust-oleum leak seal on the following. 

  • Exterior walls
  • Chimney edges
  • Drains
  • Gutters
  • Bitumen roofs
  • Windows
  • Doors

Flex Seal

Flex Seal is a rubberized sealant that can protect your RV from water, moisture, and air. This sealant works well if you want to repair the exterior of your RV. It has a more heavy-duty use as it also works well on asphalt and glass materials. You can use a flex seal for the following.

  • Repairing RV’s roof
  • Concrete, glass, or asphalt repair
  • Motorhome weatherizing 

Difference Between Leak Seal and Flex Seal

The primary difference between the two sealants lies in their ability to withstand extreme temperature changes. They both work well in hot and cold environments, but the leak seal is more temperature resistant.

But they have different material compatibility, curing time, and application methods. Due to this, they work differently on some surfaces and materials. 

Material Compatibility

Leak seal and flex seal have good material compatibility as you can use both the sealants on wood, metal, aluminum, tile, masonry, copper, glass, rubber, drywall, cement, and fabrics. 

Water Resistance

The primary difference between leak and flex seals is how they react to moisture. While both the sealants are water-tight and endure moist environments such as rain, they have some key differences.

Flex seals can withstand normal hydrostatic pressure of rain. However, it is not flexible enough to withstand continuous water submersion and extreme pressure. Thus you can’t use them for sinks, bathtubs, or toilets.

In contrast, a leaking seal can handle 16 PSI. Therefore, it is better suited to fix your RV’s toilet leakage problems.

Food Safety

Leak seals and flex seals are not food safe. Therefore, you cannot use these sealants on products such as food containers, fish tanks, or water bottles. 


Durability is critical when looking for a suitable sealant, as the seal must protect your RV from leakage problems. Leak seal and flex seal have apparent differences in durability and weather resistance. 

Flex seals are thicker and tougher than leak seals if we talk about strength. Due to the thickness, it easily adheres to the surfaces of your RV. But flex seals are more vulnerable to temperature changes than leak seals. 

The flex seals peel off under extremely hot or cold conditions and start disintegrating. In contrast, a rust-oleum leak seal works well as an outdoor solution to holes and cracks. It is UV resistant and works well under hot and cold weather conditions. 

Overall, a leak sealant is a good solution for an outdoor fix, while a flex seal works well for indoor fixes. Moreover, you can paint over the leak seal, which makes it perfect for fixing the exterior of your RV.

Leak Seal vs. Flex Seal | Which Is Better?

Flex and leak seal are great options for filling up cracks and holes to solve your RVs leakage problems.

These liquid rubber sealants are an immediate solution for repairing cracks. But, if you’re wondering which works better, you have to ask yourself one question: do you want to repair your RV’s interior or the exterior?

If you want a flexible sealant, a flex seal works better for repairing the interior. But if you’re looking for something more durable that you can also use outdoors, a leak sealant is the better option. 

Warwick Braith

Warwick Braith is a thrill seeker at heart. He loves getting outdoors and testing his limits in the wild. As a blogger for YapQ, Warwick provides readers with insights and tips on how to get the most out of their outdoor experiences. Whether it's hiking, camping, or simply exploring nature, Warwick knows how to make the most of it.

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