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  • Writer's pictureReseal UK

How Long Does Silicone Sealant Last?


Calender illustration the theme of the post. Which is how long does silicone sealant last?


When it comes to home improvement and DIY projects, silicone sealant stands as a versatile and invaluable material. From sealing gaps around windows and doors to waterproofing showers, its applications are as diverse as they are essential.


Yet, despite its widespread use, a common question persists among homeowners and DIY enthusiasts alike: How long does silicone sealant actually last?


In this article, we'll delve into the factors that influence the lifespan of silicone sealant, uncovering the secrets to maximizing its durability and effectiveness. Whether you're planning a major renovation or just curious about maintaining the integrity of your seals, understanding the science behind silicone's longevity is key.


How Long Should Silicone Sealant Last?


In my experience, silicone sealant applications can last anywhere from 2 years to 10 years and beyond.


I know that's not the concrete answer you were looking for, however the longevity of the silicone does depend on a long list of factors.


Factors That Effect The Longevity Of Silicone Sealant


Application Surface:

  • Porous Surfaces: Porous materials like wood, concrete, or certain types of stone can absorb moisture, affecting the adhesion of the sealant. It's crucial to clean the surface thoroughly and, in some cases, use a primer to create an optimal bonding surface.

Proper Application:

  • Cleaning: Cleaning involves removing any dust, dirt, grease, or contaminants from the surface. Even microscopic particles can affect adhesion, so a meticulous cleaning process is essential.

  • Priming (if needed): Priming is particularly important on highly porous surfaces. A primer creates a barrier that prevents the substrate from absorbing the sealant, ensuring a stronger bond.

Environmental Conditions:

  • Temperature: Silicone sealants have optimal application and curing temperatures. Applying sealant in extreme heat can cause it to cure too quickly, potentially leading to improper adhesion. Conversely, applying in very cold temperatures can slow down the curing process, affecting performance.

  • UV Exposure: Prolonged exposure to UV rays from the sun can lead to a breakdown of the sealant's molecular structure. This can result in discoloration, brittleness, and reduced flexibility over time. UV-resistant formulations provide extra protection against this.

  • Moisture Levels: Areas prone to high moisture levels, such as bathrooms or kitchens, may require special attention. Properly sealing and waterproofing these areas is crucial for preventing water damage and ensuring the sealant's longevity.

Quality of Sealant:

  • Ingredients and Formulation: High-quality silicone sealants typically contain a higher percentage of silicone polymers, which offer superior flexibility, adhesion, and resistance to environmental factors. Cheaper alternatives may have a higher proportion of fillers that can compromise performance.

  • Additives: Some sealants include additives like fungicides or mildewcides to inhibit the growth of mould or mildew. These can extend the lifespan of the sealant in areas prone to moisture and humidity.

Flexibility and Movement:

  • Joint Design and Movement: In areas where there's regular movement, like expansion joints in buildings or areas subject to vibration, it's crucial to select a sealant with high elasticity. This allows the sealant to flex without cracking or detaching.

  • Backer Rods: Using backer rods in larger joints can help control the depth and shape of the sealant, ensuring it maintains the necessary flexibility to accommodate movement.

Chemical Exposure:

  • Compatibility: Some chemicals, solvents, or cleaning agents can react with silicone sealant, leading to degradation. Be aware of the chemicals present in the environment and choose a sealant that is compatible with them.

Maintenance and Cleaning:

  • Regular Inspection: Periodic checks of the sealant's condition can catch any issues early. This allows for timely repairs or reapplication before damage escalates.

  • Cleaning: Regularly clean the area around the sealant to remove any debris, dirt, or substances that could compromise its effectiveness. Avoid using harsh or abrasive cleaners that could damage the sealant.

Age of Sealant:

  • Elasticity and Adhesion Over Time: As silicone sealant ages, it may gradually lose some of its original elasticity and adhesion properties. This can occur due to exposure to environmental factors and natural wear and tear.

Type of Silicone:

  • Different formulations of silicone sealant are tailored for specific applications. For example, high-temperature silicone sealants are designed to withstand elevated heat, making them suitable for applications like around stoves or ovens.

Location of Application:

  • Indoor vs. Outdoor: Outdoor sealants face a harsher range of environmental conditions, including temperature fluctuations, UV exposure, and moisture. They often require more robust formulations to withstand these challenges.

  • Exposure Levels: Sealants in highly exposed areas (such as roofs or south-facing walls) will experience more wear and tear than those in more sheltered locations.

Sealant Compatibility:

  • Ensuring that the sealant is compatible with the specific materials it will come into contact with is crucial. Incompatibility can lead to reduced adhesion or even damage to the substrate. This is particularly important when sealing joints between different materials.

By considering these detailed factors and taking appropriate measures during application and maintenance, you can significantly extend the lifespan of your silicone sealant, ensuring it remains effective for an extended period.


How To Know When To Replace Your Silicone Sealant?


Knowing when it's time to replace silicone sealant involves observing signs of wear, damage, or deterioration. Here are key indicators that it's time for replacement:


Visible Damage: Look for visible cracks, gaps, or peeling along the sealant line. These can indicate that the sealant has lost its effectiveness and is no longer providing a proper seal.


Discoloration: Over time, silicone sealant can become discoloured due to exposure to UV rays, moisture, or contaminants. If the sealant has significantly changed in colour, it may be a sign that it's deteriorating.


Loss of Elasticity: Press lightly on the sealant to test its elasticity. If it feels rigid or has lost its flexibility, it may be due for replacement. Silicone sealant should be able to flex without cracking or breaking.


Mould or Mildew Growth: If you notice the growth of mould or mildew on the sealant, it's an indication that the seal has been compromised and should be replaced. This is particularly common in areas with high moisture levels such as baths and showers.



Water Leaks or Seepage: If you observe water seeping through areas where the sealant was applied, it's a clear sign that the seal is no longer effective. This is a critical indicator that replacement is necessary to prevent further damage.


Foul Odour: A strong or unusual odour around the sealant can be a sign of microbial growth or chemical breakdown. This could indicate that the sealant has deteriorated and needs replacement.


Loose or Detached Sealant: If sections of the sealant have become loose or detached from the substrate, it's a clear sign that it's no longer providing an effective barrier.


Cracking or Splitting: Check for small cracks or splits in the sealant. These can occur over time due to environmental factors or movement in the substrate.


Loss of Adhesion: Run your finger along the sealant to check for any areas where it has lost adhesion to the substrate. If it easily peels away, it's a sign that the sealant is no longer effective.


Aging or Brittle Appearance: As silicone sealant ages, it can become more brittle and less pliable. If it looks aged or shows signs of deterioration, it's likely time for replacement.


Incompatibility with Substrate: If the sealant is not compatible with the materials it's in contact with, it may not provide a proper seal. In such cases, replacement with a compatible sealant is necessary.


Remember, regular inspections and maintenance can help catch these signs early, allowing for timely replacement and preventing potential damage. It's important to replace silicone sealant promptly to maintain the integrity of the sealed area and prevent further issues.


For a detailed look on how to expertly existing silicone sealant, see our post "How To Completely Remove Old Silicone Sealant - The Pro 4 Step Method".


Tips For Maintaining Your Silicone Sealant


Maintaining your silicone seals is essential for ensuring their longevity and effectiveness.


Here are some tips to help you keep your seals in top condition:


Regular Inspections:

  • Periodically inspect silicone seals for any signs of wear, damage, or deterioration. This allows you to identify and address issues before they escalate.

Clean the Area:

  • Regularly clean the area around the sealant to remove dirt, debris, and contaminants. Avoid using harsh or abrasive cleaners that could damage the sealant.

Avoid Harsh Chemicals:

  • Be cautious when using cleaning agents or chemicals near silicone seals. Some chemicals can react with or degrade the sealant. Choose mild, non-abrasive cleaners whenever possible.

Prevent Mould and Mildew:

  • In moisture-prone areas, like bathrooms and kitchens, take steps to prevent the growth of mould and mildew. Regularly clean and dry the area, and consider using a mildew-resistant silicone sealant.

Reapply Sealant as Needed:

  • If you notice signs of wear or damage, it's important to reapply the sealant promptly. Removing the old sealant and applying a fresh layer ensures a proper, watertight seal.

Maintain Proper Ventilation:

  • Adequate ventilation helps prevent moisture build-up, which can lead to mould growth and deterioration of the sealant. Use extractor fans in areas like bathrooms and kitchens, and try to keep windows open when those areas are in use.

Avoid Extreme Temperatures During Application:

  • When applying new sealant, avoid doing so in extremely hot or cold conditions. These conditions can affect the curing process and adhesion of the sealant.

Use Compatible Cleaners:

  • If you need to clean the sealant, use cleaners that are compatible with silicone. Avoid using products that contain strong solvents or acids, as they can damage the sealant.

Address Movement and Flexibility:

  • In areas where there's structural movement or vibration, consider using a flexible sealant that can accommodate these shifts without cracking or detaching.

Apply Backer Rods in Large Joints:

  • In larger joints, using backer rods can help control the depth and shape of the sealant. This ensures that the sealant maintains the necessary flexibility to accommodate movement.

Reapply Outdoor Sealant Periodically:

  • Outdoor sealants are exposed to harsher environmental conditions. Consider reapplying outdoor sealant every few years to maintain its effectiveness.

Choose High-Quality Sealant:

  • Invest in a high-quality silicone sealant from a reputable brand. Quality sealants tend to have better durability and resistance to environmental factors.

By following these tips, you can ensure that your silicone seals remain effective and provide long-lasting protection for your home or project. Regular maintenance and proper care will help extend the lifespan of the sealant and prevent potential issues down the line.

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