[TOP 6] Best Gutter Sealant of 2021

Gutter sealants are useful products that can instantly seal off cracked or leaking surfaces. If the sealants are applied immediately to such problem surfaces, it can lead to widespread damage to the building’s structure and the goods inside.

It is advised that every household should keep some kind of sealant at home for such emergencies. In this best gutter sealant review, we are trying to prepare a list of some gutter sealants.

Best Gutter Sealant Reviews & Full Details

#1. Rust-Oleum 275116 Stop Rust Leak Seal

Rust-Oleum 275116 Stop Rust Leak Seal

Rust-Oleum LeakSeal is a rubberized protective coating. It can seal common cracks and leaks at homes, factories and commercial establishments. It is one of the best gutter sealant that can effectively seal off the problem areas.

Its sealing can effectively prevent rust, corrosion, and moisture from affecting the surface. This gutter sealant offers complete waterproof protection to the surface. Its sealing effects are almost instant. This can be used for sealing cracks and leaks in roofs, flashing, PVC, and gutters.

Key Features

  • Needs to be applied with a brush, creates water-tight barrier
  • Dries quickly, good for hard-to-reach area, crystal clear
  • High build oil-based formula, flexible rubber coating
  • Sealed area can be coated with paint or latex

#2. Geocel Corp 29402 Instant Gutter Seal

Geocel Corp. 29402 Instant Gutter Seal

This is great stuff. It comes in a tube and the content looks a goopy silver grey. It finishes the job of sealing an opening or leaks in minutes. The next you look at the problem area, you only find a solid seal. Compared to many products in this category, this gutter sealant is a clear winner. This can offer effective sealing results in a wide range of surfaces including flashing, PVC, roofs, and gutters.

Key Features

  • Can withstand temperature variations in the range of -10 to 65 degrees
  • Reviews suggest Geocel works well with old but cleaned aluminum gutters
  • It’s not made of silicone, yet it is effective and easy to use
  • Sealed area can be coated with paint or latex

#3. Dap-18188 Gray Gutter and Flashing Sealant

Dap 18188 Gray Gutter and Flashing Sealant

It’s amazingly sticky stuff and does the job of sealing a leak or crack fairly efficiently. When you apply this to a problem area, you should be assured of solving the problem for the long term. You can use this just anywhere from the windows of your camper to the gutters in your home. It may be a little messy as it is thicker and stickier than other caulks.

Key Features

  • May take a day to completely sit on the problem area
  • You can use a different product on the edges for a better finish
  • Sometimes, you may have to warm the tube to squeeze out of the content
  • It’s thicker and more sticky than usual gutter sealants

#4. Liquid Rubber Waterproof Sealant, LR

Liquid Rubber Waterproof Sealant

This must be one of the best gutter sealant. It is an ideal solution for leaks in different kind of roofs such as those with flat, metal, and sloped variations. It can also be used foundations, planter boxes, ponds, basements, metal, sheds, and wood, concrete. As a powerful sealant, it boasts great qualities. Its high build formula boasts 1000% elongation that prevents adhesion failure. It has a stable UV profile that ensures there is little degradation due to exposure to sun.

Key Features

  • Water-based, liquid rubber sealant containing no solvents
  • Safe for pets and humans alike, there are no volatile organic compounds (VOCs) or harmful odors
  • Good for both indoor and outdoor surfaces
  • Effective for seams, protrusions, bridge joints, vents, gaps

#5. Flex Seal Liquid Rubber in a Can, White

Flex Seal Liquid Rubber in a Can

It’s a non-toxic, non-hazardous, UV-resistant liquid rubber sealant. It is particularly good to withstand rain and water. It is also a heavily advertised product on TV. Although it comes in a liquid form, it flows thick and sticks strong. It takes roughly 24 hours to dry but retains its rubbery texture and feel. You will need mineral spirits to clean the excess sealant. It’s chemical-resistant and prevents mildew rust and corrosion.

Key Features

  • Though thick and sticky, it is easy to work with
  • The problem surface needs to be cleaned properly for this to stick
  • It’s smooth and you can pour, brush, dip or roll on the affected surface
  • Offers flexible, watertight, rubberized coating

#6. Gorilla Clear 100% Silicone Caulk

Gorilla Clear Silicone Caulk

This is a sturdy clear silicone sealant. It works great with auto, marine, gutters, plumbing, windows, bath, and kitchen. It does not more than 30 minutes to get permanently fixed in the problem area. This is a waterproof sealant with mild and mildew resistant properties. This does not crack, shrink or turn yellow with time. Before applying Gorilla Clear Silicone Caulk sealant, the surface must be cleaned for old sealant, oil, grease, and dirt.

Key Features

  • Use a caulking gun to apply the sealant, best above 40F
  • Wipe excess sealant off the surface immediately with dry cloth or foam
  • Waterproof, and resistant to mold and mildews
  • 100% silicone and versatile sealant that looks translucent clear after drying up

Buying Guide: Gutter Sealant

There are different kinds of gutter sealants available in the market and sometimes it can be difficult to choose a particular one for your purpose. But there are certain things that you should bear in mind to zero in on the best gutter sealant for your requirements.

There are mainly two types of sealants: rubber-based and silicone-based sealants. Rubber-based sealants work better in wet and chemical-laden environments while silicone sealants have a better look and finish. They have different degrees of resistance to sun and UV rays, which tend to wear down the sealant quickly. The rubber sealant is considered more resistant to sun and UV rays.

(FAQs) Frequently Asked Questions

How long does gutter sealant last?

There are different kinds of gutter sealants in the market and they tend to have varying life spans after they are applied to the problem area. Usually, a sealant should do the emergency job of sealing off a leak or crack immediately and effectively. There are different factors that wear it off over a period of time that can be from a few weeks to up to 10 years.

What is the best gutter sealant?

Geocel Corp 29402 is the best gutter sealant because It seals instantly, stays permanently flexible, a wide range of surfaces flashing, PVC, roofs, gutters, and more.


In this gutter sealant review, we have considered some of the best gutter sealants available on the market. It is always advisable to have some of them at home at all times so that you can respond to a leak or crack immediately. In this review, we have evaluated the top 6 sealant products. You can choose one or two for your projects and requirements.

Our Recommendation – Rust Oleum Or Geocel Corp

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