Everything About Thermoplastic Sealants

By Editorial Team

Updated on July 24, 2025

Thermoplastic Sealants

Sealants are a crucial part of insulating and shielding structures from bad weather and water leaks. Among the different sealants retailed, thermoplastic sealants differ on account of their unique properties and versatility. This comprehensive guide delves into all thermoplastic sealant-specific characteristics, including their pros and cons, as well as methods of application. We will also take a look at the difference between thermoplastic and silicone sealants, as well as tips for applying such products effectively.

What Is a Thermoplastic Sealant and What Is It Used For?

Thermoplastic Sealants

Thermoplastic sealants are materials used to seal joints and cracks found in a wide range of construction processes. They’re made with plastic polymers, which soften when heated and harden when cooled. This type of sealant has excellent adhesion and flexibility, rendering its use ideal in settings subjected to temperature variations. Outdoor sealants and thermoplastic sealants are often used in such situations. 

What are the advantages of thermoplastic sealants?

  • Durability and flexibility: Thermoplastic sealants are extremely durable and retain their flexibility even after years of exposure to the elements. Said flexibility allows the sealant to absorb shifts in construction materials without cracking.

  • Premium adhesion: It adheres to a variety of surfaces, including metal, concrete, wood, and PVC without issue. Its exceptional adhesion guarantees an effective and durable seal.

  • Weatherproof: Thermoplastic sealants withstand harsh weather, including UV rays, rain, and temperature variations. This makes it especially suitable for outdoor use. Using insulating thermoplastic sealants also helps keep out exceptional instances of heat or cold.

  • Wide temperature application range: Said sealants can withstand a wide temperature application range, from -29°C to 71°C, which makes these products versatile enough to withstand diverse weather conditions.

  • Ease of use: Thermoplastic sealants are easy to apply using a caulking gun. The product’s quick-dry properties make it so it can be handled shortly after application. As such, applying a thermoplastic sealant is a relatively simple task.

What are the drawbacks of sealing with thermoplastic sealants?

  • More expensive than traditional sealants: Thermoplastic sealants tend to be pricier than other types of sealants, which can increase overall project costs. 

  • Susceptible to solvents: Such sealants are vulnerable when exposed to certain solvents, which can limit their use in specific environments. 

  • Requires a caulking gun: The application of thermoplastic sealants necessitates the use of a caulking gun, which can be rather impractical for some users. 

What Are the Primary Thermoplastic Sealant Applications?

Thermoplastic Sealants

Exterior/Outdoor Window Seals

Thermoplastic sealants are ideal for sealing interior and exterior window frames. 

  • Prevent air or water leaks: Thermoplastic sealants effectively prevent water or air from leaking around windows, thus improving thermal and acoustic insulation.

  • Improve energy efficiency: By preventing air leaks, such sealants contribute to improving a building’s energy efficiency, which, in turn, reduces heating and air conditioning costs. 

  • Minimize noise pollution: Hermetic window seals also help minimize noise pollution, making for quieter indoor settings.

Roof Sealants

Thermoplastic sealants are also used as roof sealants. 

  • Prevent water leaks: They’re used to seal roof joints and cracks, preventing water from seeping through the structure and causing structural damage.

  • Protect against weather-related damage: Thermoplastic sealants protect roofs against harsh weather-related damage, prolonging the roof’s service life. 

Other Applications

  • Expansion joint filler: They’re perfectly suited to seal concrete expansion joints, allowing the structure to shift without compromising its watertight properties. 

  • Plumbing fitting seal: Thermoplastic sealants are also used to seal plumbing fittings, preventing leaks and ensuring durable, leak-proof installations.

  • Appliance and light fixture seal: They can be used to seal the joints around appliances and light fixtures, ensuring a sleek and leak-proof finish. 

How to a Apply Thermoplastic Sealant

Thermoplastic Sealants

Prepare Surface

Before applying the sealant, prepare the surface accordingly. Clean the zone in question to remove dust, dirt, and remnants of the former sealant. Make sure the surface is dry and devoid of contaminants. 

Apply Sealant

Use a caulking gun to apply the thermoplastic sealant along the joints in an even manner. Apply constant pressure to ensure a regular amount of sealant is dispensed. Applying the thermoplastic sealant correctly is paramount for maximum efficiency. 

Finishing Touches & Clean Up

Once the sealant is applied, smooth out the product using a dedicated tool to ensure proper adhesion and a professional-looking result. Immediately wipe off any excess sealant using a clean rag. 

Thermoplastic vs. Silicone Sealant: Which Type Is Best?

Thermoplastic Sealants

What are the key features of silicone sealants?

  • Exceptional adhesion to a wide range of materials: Silicone sealants have exceptional adhesive properties, bonding to a variety of materials, including glass, metal, and tiled surfaces.

  • Mould- and fungi-resistant: It withstands mould and fungi, making it an ideal product to apply in bathrooms and kitchens.

  • Flexibility and durability: Silicone sealants retain their flexibility and durability even after prolonged exposure to harsh weather and UV rays.

Guide to Choosing Between Thermoplastic or Silicone Sealants

What’s best, a thermoplastic or silicone sealant? The ideal choice ultimately comes down to its specific application and the material on which it will be applied.

  • Consider product application and surface material: Select a sealant based on its intended use and whether it's suited to the material on which it will be applied. Thermoplastic sealants are especially suited to outdoor applications and frequently shifting surfaces.

  • Assess the required flexibility and weatherproofing: If flexibility and premium UV resistance are what you're looking for, silicone sealants are better suited for the job.

  • Bear in mind your budget and user-friendly factor: Consider budget and ease of application. Thermoplastic sealants can be more expensive, yet deliver longer lasting results.

Maximize Efficiency and Durability with Thermoplastic Sealants

Thermoplastic Sealants

Thermoplastic sealants are a reliable and durable solution for a slew of sealer-required applications, from windows to roofs. Their flexibility and weatherproofing make it the best product for projects requiring long-lasting results. However, it’s important to choose a situation-specific sealant, while also considering surface materials, weather conditions, and budget.

For the best results, follow proper application guidelines and consult an industry professional if need be. To learn more about sealants and for situation-specific advice, check out our website or contact our team of experts at RenoQuotes.com. 

Want to learn more about sealing and sealants? Check out these articles:

FAQ

How do you remove thermoplastic sealant?

To remove thermoplastic sealant, start by softening it with a heat gun or hair dryer on a low setting. Once the sealant becomes pliable, use a utility knife, scraper, or putty knife to carefully peel or scrape it away. After removal, clean any residue with a solvent like mineral spirits, if compatible with the surface.

How do you smooth thermoplastic caulking?

Thermoplastic caulking should be smoothed immediately after application, before it skins over. Use a caulking tool, a gloved finger, or a slightly soapy finger to smooth the bead evenly. Be sure to work quickly, as thermoplastic formulas can begin to set within minutes.

How long does it take for thermoplastic waterproof sealant to dry?

Thermoplastic sealants typically dry to the touch within 30 minutes to 1 hour, depending on temperature, humidity, and bead thickness. However, full curing and waterproof performance may take 24 to 48 hours. Always check the manufacturer's specifications for exact drying times.


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