Sealant: A Comprehensive Guide to Function, Types, and Uses

by Joost Nusselder | Updated on:  June 19, 2022
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Sealant is a material that’s applied to a surface to create a seal or barrier against liquids, gases, and solids. It can be used to protect everything from your teeth to your house.

In this guide, I’ll explain how sealant works and when you should use it. Additionally, I’ll share some tips for applying it properly.

What is sealant

The Many Functions of Sealants

Sealants perform a crucial role in serving as a barrier against moisture, dust, and other harmful chemicals. They are used to contain liquids or gases and provide a coating to protect surfaces from damage. Sealants are effective in waterproofing structures and providing thermal, acoustical, and fire protection.

Filling Gaps and Smoothing Surfaces

Sealants are used to fill gaps and cracks in structures, providing physical adhesion and maintaining the expected performance of the structure. They are also used for smoothing surfaces, providing a clear and functional appearance.

Formulation and Application

Sealants are available in a variety of formulations, including organic and elastomers. They are easy to apply and offer simplicity and reliability in their application. Sealants are designed to accommodate movement in structures, ensuring that they maintain their sealing properties over time.

Functional Properties

Sealants offer a range of functional properties, including adhesion, waterproofing, and fire protection. They are used in a variety of applications, including construction, automotive, and aerospace industries.

The Early Days of Sealants: From Ancient Clay to Modern Dental Sealants

Sealing has been a practice since ancient times, with civilizations in the Western world using various materials to seal objects and structures. Here are some examples:

  • In the Indus Valley Civilization, people used clay to seal their homes and prevent water from seeping in.
  • In ancient religious practices, sealing was used to keep sacred objects and texts safe from damage or tampering.
  • Carbohydrates like wax were used to seal containers of food and drink to keep them fresh.

Sealing in Dental Health

Sealing has been used in dental health for centuries, with early civilizations using various materials to fill pits and fissures in teeth. Here are some examples:

  • In the twelfth century, a mixture of honey and powdered rock was used to fill pits and fissures in teeth.
  • In the Middle Ages, beeswax was used to seal teeth and prevent decay.
  • In the early 1900s, dentists used a mixture of silver and tin to fill pits and fissures.

The Development of Modern Dental Sealants

Modern dental sealants were first developed in the 1960s as a way to prevent tooth decay. Here are some key developments:

  • In the 1960s, dental sealants were made from acrylic and were difficult to place.
  • In the 1970s, dental sealants were made from a resin material that was easier to place and more effective at preventing decay.
  • Today, dental sealants are made from a plastic material that is applied to the tooth and hardened with a special light.

Types of Sealants: A Comprehensive Guide

Sealants are materials that are commonly used in construction and building service to prevent the flow of certain materials or changes in state. They are designed to close difficult gaps and prevent the entry of air, water, or other substances. Sealants come in a variety of types, each intended for a specific function or task.

Common Types of Sealants

Sealants can be broadly classified into three categories based on the material they are made of:

  • Acrylic-based sealants:
    These are the most common type of sealants and tend to be low cost. They are easy to apply, clean, and maintain. They are commonly used for filleting, maintenance, and sealing small gaps. Acrylic sealants are not highly resistant to extreme temperatures and are best used for interior work.
  • Polysulfide-based sealants:
    These are highly resistant to extreme temperatures and are commonly used for exterior work. They are tough and form a highly durable seal. However, they are expensive and require a long time to set.
  • Silicone-based sealants:
    These are highly popular and are known for their quick setting time. They are highly resistant to extreme temperatures and are useful for sealing gaps in metal, stone, and other materials. They tend to be expensive and require a lot of maintenance.

Choosing the Right Sealant

Choosing the right sealant for a particular job is important. Some factors to keep in mind when choosing a sealant include:

  • The material being sealed
  • The specific function required
  • The environment in which the sealant will be used
  • The required maintenance
  • The cost of the product

Where to Apply Sealant: Finding the Ideal Application for Your Needs

  • Sealants are commonly used in construction to protect against water and air infiltration.
  • They can be applied to a variety of surfaces, including metal, stone, and sheet materials.
  • Sealants are also used to fill gaps and irregularities between materials to prevent pests from entering.

Bathroom and Shower Applications

  • Sealants are ideal for bathroom and shower applications, where water can easily seep through gaps and cause damage.
  • They can be used to seal around windows, doors, and tile surfaces to prevent water from entering.
  • Latex and silicone sealants are commonly used in these applications due to their ability to form strong bonds with surfaces.

Fuel and Heavy Duty Applications

  • Sealants can be used to seal fuel tanks and other heavy-duty applications.
  • The type of sealant used in these applications is important to ensure proper bonding and protection.
  • Professional skills may be required for these applications to ensure the sealant is applied correctly and able to withstand heavy use.

The Main Thing to Remember

  • When considering where to use sealant, it’s important to remember that the type of sealant used should be appropriate for the intended application.
  • While sealants are easy to work with, proper application is important to ensure a strong bond and effective protection.
  • Whether you’re familiar with sealants or entirely new to them, taking the time to find the best sealant for your needs is worth the effort in the long run.

Sealants vs Adhesives: What’s the Difference?

Sealants and adhesives are two common building and construction products that differ in their composition and strength. Adhesives are designed to hold surfaces together, while sealants are used to fill gaps and resist relative movement of the surfaces to which they are applied. Adhesives are generally stronger than sealants, but sealants provide the assembly with much more flexibility. Adhesives are composed of chemicals that cure and form a solid bond between two substrates, while sealants lack the high adhesion strength of adhesives.

Cure Time and Holding Power

Sealants and adhesives differ in their cure time and holding power. Adhesives typically cure faster and have a higher holding power than sealants. Sealants, on the other hand, provide greater flexibility and can resist relative movement of surfaces. When choosing between sealants and adhesives, it’s important to consider the specific application and the desired performance.

Manufacturer’s Recommendations

It’s important to follow the manufacturer’s recommendations when choosing between sealants and adhesives. Different materials require different types of sealants and adhesives, and using the wrong product can result in a lack of adhesion or performance. Some materials may require a high-strength adhesive, while others may require a flexible sealant. Proper selection of sealants and adhesives is critical to the success of any building or construction project.


So, that’s what sealant is and how it’s used. It’s a great product for sealing cracks and protecting surfaces from damage, and it’s been used for centuries by both the ancient and modern civilizations. You just have to remember to use the right sealant for the right job, and you’re good to go. So, don’t be afraid to give it a try!

I'm Joost Nusselder, the founder of Tools Doctor, content marketer, and dad. I love trying out new equipment, and together with my team I've been creating in-depth blog articles since 2016 to help loyal readers with tools & crafting tips.