Flex Seal Reviews: Does It Work? 2021

Roof leaks can arise at any given time, and it is necessary to fix a leak in the roof once and for all. If you need to repair a crack in the ceiling, barrel, pool, or any other surface or object, you will need a high quality and reliable material that is not only secure but also easy to apply and can serve for a long time. I believe that Flex Seal is what you need to fix all these problems and prevent their re-occurrence in the future.

Flex Seal is an excellent material that guarantees reliable damp proofing. Unfortunately, builders have been missing this perfect material for quite a long time. Initially, builders would use rolled materials – such as roof felt – that were put end-to-end and slits sealed separately.

But, the integrity of their sealing would be compromised by time. The cover of roof felt materials would lose firm adhesion with the base leading to exfoliation; joints would dissolve and water would ingress inside. Today, Flex Seal is one of the best options for fixing holes and cracks on different objects and surfaces.

In our Flex Seal reviews, we will be exploring everything you need to know about this rubberized sealant. Follow me as we uncover the features and benefits of this ingenious product.

Flex Seal Reviews – At a Glance

Product TitleFlex Seal Spray Rubber Sealant Coating
Features• Proprietary Formulation
• Flex Seal is Multipurpose
• Flex Seal is Adaptable
• Extremely Easy to Use
Weight2 pounds
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Flex Seal Spray Rubber Sealant Coating 14OZ, Brite (2 Pack): Brief Overview

Flex Seal is a liquid rubberized coating (available in a portable aerosol spray can or gallon container) that dries out to form a durable, watertight barrier for repairing cracks and holes on objects and surfaces. It works by expelling the liquid rubber to stop leaks fast, providing an efficient way to seal, coat, and protect almost anything imaginable. Flex Seal is easy to use by simply brushing, pouring, dipping, or rolling the liquid rubber anywhere to create a flexible, waterproof coating or sealant.

Regarding composition, Flex Seal liquid comprises emulsified bitumen with added polymers and stabilizers. The patent-pending proprietary formulation commences as a thick liquid, which then dries out to create a flexible and ultra-strong waterproof rubberized sealant to protect and stop leaks fast. Flex Seal forms a rubberized coating on nearly any surface and seals out air, moisture, and water to prevent corrosion and rust.

is flex seal toxic

Flex Seal liquid can never sag or drip during the hot summer; neither is it toxic. The rubber stays flexible and permeable for years to come. It is excellent for fixing roof leaks, mobile home roofs, vent pipes, skylights, chimneys, foundations, asphalt shingles, drip edges, etc.

Key Features of Flex Seal Spray Rubber Sealant Coating

Proprietary Formulation

Flex Seal liquid is specially formulated as thick, hard-wearing, and mastic rubberized sealant. It is designed to spray out as liquid so that it can permeate the cracks and holes and dry out to create a flexible, waterproof rubberized coating. It can freeze instantly and convert into a solid phase in minutes.

The watery base of the Flex Seal prevents evaporation and the formation of toxic substances. The product is gaining fame in Northern regions as it can withstand abrupt zero weather. Moreover, the material lacks the main disadvantage common in bitumen – aging effect.

Flex Seal is Multipurpose

Flex Seal is your go-to option if you want to repair a variety of surfaces without breaking the bank. It can fix any object or surface both inside and outside your house, including roofs, gutters, drywall, and more. The product does not only function as a water sealant, but it also serves as an efficient insulator.

This is the reason most people brush or roll the Flex Seal on their basement walls in preparation for the winter. Actually, you can do so much with the Flex Seal liquid rubberized sealant. Most importantly, you can apply it on a wet surface or a moist environment in case of an emergency.

Flex Seal is Adaptable

Adaptability is essential when it comes to sealing cracks and holes on objects and surfaces. Flex Seal dries out to form a watertight and flexible coating no matter the object or surface you apply it onto. This flexible rubberized sealant expands and contracts to suit a ton of objects and surfaces.

flex seal temperature range

Flex Seal works best on dry surfaces, although you can still spray it onto wet objects and surfaces when an emergency arises. All you have to do is ensure the surface is free of dirt, dust, and grease before applying the sealant. You are free to use it on nearly anything imaginable: porcelain, wood metals, glass, vinyl, drywall, and so much more.

Extremely Easy to Use

Using the Flex Seal liquid rubberized sealant is a piece of cake. Its use revolves around four key things – brushing, pouring, rolling, or dipping. You can roll or brush it on any surface using an even sweeping motion. Alternatively, you can dip any object into the liquid rubberized sealant in a light swirling action.

If you choose the dipping approach, make sure to drain the excess Flex Seal liquid back into the can to avoid waste. For surfaces that prove hard to reach, you can seal those cracks by pouring the Flex Seal liquid directly into the holes. The sealant will fill those hard-to-reach cracks and holes through gravity.

Flex Seal is Resilient

Flex Seal is a robust and genuinely elastic material which never exfoliates at rapid temperature changes, mechanical damages, and even vibration. The product composition is inflammable and proves sturdy against basic construction mixes and chemicals. Flex Seal works even in extreme weather conditions.

You can use it safely below 0 degrees Fahrenheit and above 250 degrees Fahrenheit. With Flex Seal, repeating the work every year is not necessary. It neither sags nor drips in the summertime, plus it never cracks in the cold months. Flex Seal never peels, cracks, or loses effectiveness for many years.


  • Stop leaks fast in their tracks
  • Easy to use – brush/roll, pour, or dip
  • Remains flexible and pliable for years
  • Forms a breathable, durable, watertight, and non-slip barrier
  • Prevents corrosion and rust
  • Chemical & mildew resistant
  • Will not drip or sag in the summer heat
  • Will not peel or crack in the winter cold
  • Apply on dry on wet surfaces without mess


  • Cannot be used in non-ventilated rooms because of the strong smell

Is Flex Seal toxic?

Flex Seal liquid rubberized sealant is non-toxic and food grade safe. You can use it at any condition without any mess or concern. Since it is non-hazardous, you will be able to use it around animals and plants – even inside a pond with live fish!

What is Flex Seal temperature range?

Flex Seal liquid rubberized sealant has an extensive temperature range. You can use it between -80 and 350 degrees Fahrenheit. However, experts recommend using it between 32 and 120 degrees Fahrenheit for best results.

Does Flex Seal work on concrete?

Yes. You can use the Flex Seal on virtually any surface you can imagine. It works on concrete, fabric, aluminum, masonry, rubber, cement, porcelain, vinyl, and so much more. Additionally, Flex Seal will not drip or sag in the summer heat; neither does it peel nor crack in the cold months.

Does Flex Seal work on copper pipes?

Yes. Flex Seal stops cracks and leaks on various objects and surfaces, not excluding copper pipes. It is understandable that even the smallest leaks in a copper pipe may result in water damage. Flex Seal is the real solution when it comes to sealing those annoying leaks that can cost you huge expenses on water bills.

Final Verdict

Flex Seal liquid rubberized coating forms a durable waterproof barrier to seal out cracks and holes on different objects and surfaces. It stops leaks fast and protects surfaces against rust and corrosion. The product proves useful for fixing cracks, leaks, and holes and delivers impressive results for a bathroom caulk.

Flex Seal lasts for quite a long time to seal out air, water and moisture. Read Flex Seal reviews Amazon and make an informed purchase decision now. Hopefully, this review will help you decide whether this product is right for your upcoming household project.

Kathy Smith

Hi, I am Kathy Smith. I am chief chef in KitchenGearPros. I am also a freelance blogger. I share my cooking related experience and knowledge.

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