Best Sealant Between Concrete and Wood: Selection and Application

Sealants play a vital role in the construction industry, particularly when bonding concrete and wood. They are essential for ensuring the durability and protection of these materials. Let’s delve into the importance of sealants for concrete and wood, their common uses, and the best types available in the market.

Importance of Sealants for Concrete and Wood

Sealants are crucial for creating a tight bond between concrete and wood. They prevent the wood from rotting and protect the integrity of the building. Here’s why they are essential:

  1. Protection Against Moisture and Pests: The critical joint between the concrete foundation and the wood framing sole or sill plate requires the best sealant to prevent moisture and pests from accessing the wood. Products like TERM® Sill Plate Barrier and synthetic rubber are commonly used.
  2. Air Sealing at the Framing Stage: Adequate air sealing at the framing stage helps maintain the building’s integrity and creates a comfortable and safe indoor environment. It helps keep up with evolving energy codes, limiting outdoor air infiltration, preventing moisture deposition within the wall cavity, and keeping insects and other critters away.
  3. Creating an Airtight Seal: Effective sealing must address all three gaps between the foundation and framing. Builders often use foam sill seal or synthetic rubber for this purpose. The TERM Sill Plate Barrier is considered one of the best sill sealers, providing a full vapor and waterproofing barrier and blocking moisture and air from the exterior and interior.
  4. Sealing Outside and Inside Gaps: Fluid-applied sealants like Polyguard BB GF seal the joints connecting the framing to the foundation. They form a rubber barrier to the home’s interior and exterior base and protect the vulnerable bottom edge of the wood sheathing against splash-back.
  5. Benefits of Polyguard BB GF: This sealant offers superior shore hardness, large joint and seam filler capability, Class A surface burning rating, environmentally friendly properties, exceptional adhesion, and wet surface applications.
  6. Choosing the Best Sealant: Selecting the best sealant between concrete and wood contributes to a tight building envelope, helps meet modern energy codes, limits damaging condensation in the wall cavity, and stops pests from entering the wall system. Quality sill plate sealers like TERM® Sill Plate Barrier and fluid-applied flashings like Polyguard Blue Barrier Gap Filler are recommended.

Common Uses of Sealants

Sealants are commonly used in the following areas:

  • Sill Plate Sealing: To prevent moisture and pests from accessing wood framing.
  • Air Sealing: To protect the building’s integrity and create a comfortable indoor environment.
  • Gap Filling: To bridge gaps up to 3/4-inch on multiple substrates like concrete and wood.
  • Waterproofing: To provide a full vapor and waterproofing barrier for wood framing against moisture from concrete.

Types and Choices of Sealants

Sealants are essential in various applications, especially for bonding materials like concrete and wood. The choice of sealant can significantly impact the bond’s effectiveness, durability, and appearance.

Silicone Sealants

  • 100% Silicone Sealant: Known for its flexibility and durability, 100% silicone sealant is waterproof and resistant to mold and mildew. It’s an excellent choice for caulking baseboards but is not paintable. A popular example is Gorilla 100% Silicone Sealant.
  • Silicone-Latex Hybrid: Combining the elasticity of silicone with the paintability of acrylic, this type of sealant offers good flexibility and adhesion. It’s suitable for porous surfaces like masonry or brick.

Polyurethane Sealants

  • Masonry Caulk: This polyurethane-based sealant often contains sand to add texture. It’s heat resistant and frequently used around fireplaces.
  • Butyl Rubber Caulk: Highly flexible, butyl rubber caulk works well for sealing guttering but may not be suitable for caulking baseboards.

Other Choices

  • Acrylic Latex: Available with silicone for superior flexibility, this type offers excellent adhesion and is mold and mildew resistant. An example is DAP Alex Plus Acrylic Latex.
  • Elastomeric Caulks: These are not a type but an indication of the caulk’s elasticity. They must remain flexible so they don’t get brittle or crack when dry.

Selection Factors

When choosing a sealant, consider the following factors:

  • Quality and Durability: Select a reputable manufacturer’s product that should last a minimum of 25 years. Some products come with a lifetime guarantee.
  • Curing Time and Paintability: Consider the drying time, especially if the area needs to be used quickly. Latex dries fastest, while pure silicone takes longer.
  • Gap Size and Adhesion: Consider the gap-filling properties and how well a particular caulk adheres to the chosen material.
  • Mold and Mildew Resistance: If used in damp or humid environments, ensure the caulk is waterproof and resistant to mold and mildew.

What specific applications might require a silicone-latex hybrid over pure silicone?

Sealants are vital to various industries, including construction, automotive, and more. The choice between hybrid polymer sealants and traditional silicone sealants depends on the application’s specific needs.

Hybrid Polymer Sealants blend polyurethane and silicone, offering superior bonding properties, exceptional flexibility, and long-lasting durability. They are also resistant to moisture, UV rays, and chemicals. Some of the advantages include:

  • Better Bonding: Forms strong and permanent bonds.
  • Durability: Known for excellent durability and lasting power.
  • Flexibility: Highly flexible, preventing cracking over time.
  • Resistance: Higher resistance to moisture, UV rays, and chemicals.
  • Aesthetics: Can be painted over, suitable for applications where aesthetics are essential.

On the other hand, Silicone Sealants are known for their resistance to extreme temperatures, moisture, and UV light. They are generally more affordable and have faster curing times but cannot be painted over.

Applications for Hybrid Polymer Sealants might include:

  • Sealing high-traffic expansion joints in buildings, roads, and bridges.
  • Bonding and sealing of metal and plastic applications.
  • Marine and automotive applications.
  • High-performance sealing in window framing, roofing, and plumbing applications.

How does the choice of sealant impact the long-term maintenance and appearance of a bond between concrete and wood?

The choice of sealant plays a crucial role in the long-term maintenance and appearance of a bond between concrete and wood. With superior bonding properties and flexibility, hybrid polymer sealants can withstand harsh weather conditions, vibrations, and temperature changes without cracking or peeling. This ensures a long-lasting and aesthetically pleasing bond.

On the other hand, silicone sealants, while resistant to extreme temperatures and moisture, may not bond as well to certain substrates and cannot be painted over. This might affect the appearance and require more frequent maintenance.

In what scenarios would butyl rubber caulk be preferred, and why might it not be suitable for caulking baseboards?

Hybrid Polymer Sealants are known for their flexibility and ability to expand and contract with surfaces. They are also paintable and can be used on a broader range of substrates, including metals, plastics, glass, and wood.

Silicone Sealants are highly flexible and ideal for applications requiring stretchability, such as plumbing and roofing.

A hybrid polymer sealant might be preferred in scenarios where superior bonding, flexibility, and aesthetics are required. Butyl rubber caulk might not be suitable for caulking baseboards if it lacks the adhesive strength, flexibility, or appearance required for that specific application.

Best Practices and Common Mistakes

Sealing between concrete and wood is a crucial task that requires attention to detail and proper techniques. Whether you’re sealing the bottom plate to a concrete or working on the foundation of a house, understanding the best practices and common mistakes can make a significant difference in the quality and longevity of the seal.

Best Practices

  1. Preparation: Ensure that both surfaces are clean, dry, and free of dust or debris. Any existing sealant or paint should be removed for the best adhesion.
  2. Choose the Right Sealant: Select a sealant for bonding concrete and wood. Consider factors like flexibility, curing time, and weather resistance.
  3. Use the Right Tools: Utilize a caulking gun for precise application, and have a spatula or finger dipped in soapy water ready to smooth the sealant.
  4. Apply in Optimal Conditions: Avoid applying sealant in extreme temperatures or wet conditions, which can affect curing and adhesion.
  5. Follow Manufacturer’s Instructions: Always read and follow the instructions provided by the sealant manufacturer for the best results.

Common Mistakes to Avoid

  1. Over-Applying Sealant: Using too much sealant can lead to a messy appearance and may not provide additional benefits. Apply a bead that’s large enough to fill the gap without overflowing.
  2. Ignoring Joint Movement: Consider the potential movement between the concrete and wood. Using a sealant that’s too rigid for a joint that will move can lead to cracking.
  3. Not Allowing Proper Curing Time: Allow the sealant to cure for the recommended time before exposing it to stress or moisture.
  4. Ignoring Safety Precautions: Always use gloves and eye protection, and ensure proper indoor ventilation.

Moisture Barriers and Environmental Considerations

Moisture barriers play a vital role in sealing between concrete and wood, offering protection and durability. They also have an environmental impact that should be considered.

Types and Benefits of Moisture Barriers

  1. Tar Paper: Often used as a sealant between concrete and wood, tar paper is water-resistant and offers a robust barrier against moisture.
  2. Plastic Sheeting: Provides an effective moisture barrier and is often used in construction to prevent water infiltration.
  3. Eco-Friendly Options: Some moisture barriers are made from recycled materials, contributing to sustainability.

Installation and Sustainability

  1. Proper Installation: Moisture barriers must be installed correctly to provide effective waterproofing. This includes overlapping edges and sealing seams.
  2. Consider Environmental Impact: Choose eco-friendly materials and consider the long-term impact of the barrier on the environment.

Recommended Brands and Products

When it comes to sealing between concrete and wood, the choice of brand and product can significantly impact the quality and longevity of the bond.

1. Cedarshield Wood Treatment

  • Price: $70.00 USD
  • Description: Specifically designed for exterior wood waterproofing, Cedarshield Wood Treatment offers a robust solution for protecting wood surfaces.

2. wedi Joint Sealant

  • Price: $34.99 CAD
  • Description: Ideal for sealing joints, wedi Joint Sealant provides a reliable and long-lasting bond.


  • Price: $29.95 USD
  • Description: Known for its versatile application, ULTIMATE SEALANT offers quality sealing for various surfaces, including concrete and wood.

4. Hi-Gloss 30% Clear Solvent Sealer

  • Price: $159.95 USD
  • Description: This solvent sealer is suitable for concrete and wood surfaces and is designed for high gloss and clear finish.

5. Surebond – Security Sealant SB-190 Everseal Gray

  • Price: $22.50 CAD
  • Description: Surebond offers a security sealant that ensures a strong and durable bond between various materials, including concrete and wood.

DIY vs. Professional Services

When sealing between concrete and wood, you might be torn between doing it yourself (DIY) or hiring professional services. Both options have pros and cons, and understanding them can help you make the right decision for your project.

DIY Sealing


  1. Cost-Effective: DIY sealing can be done for less than $20, making it a budget-friendly option.
  2. Personal Satisfaction: Completing the project yourself can provide a sense of accomplishment and control over the process.
  3. Flexibility: You can work at your own pace and adjust as needed.


  1. Skill Required: Proper sealing requires careful attention to detail and some expertise. Mistakes can lead to further problems.
  2. Time-Consuming: Depending on the complexity, it may take longer to complete the project yourself.

DIY Guide: The Family Handyman provides a step-by-step guide on how to seal cracks in concrete, including the tools and materials required, such as foam backer rod, mineral spirits, and polyurethane caulk.

Professional Services


  1. Expertise: Professionals have the skills and experience to ensure a quality job.
  2. Time-Saving: Hiring a contractor can expedite the process, especially for larger projects.
  3. Warranty: Many professional services offer warranties on their work, providing peace of mind.


  1. Cost: Professional services can be more expensive, depending on the scope and complexity of the project.
  2. Availability: Finding the right contractor and scheduling can sometimes be challenging.

When to Choose DIY or Professional Services?

  • DIY: If you have some experience with home improvement and are working on a smaller project, DIY might be the right choice. It allows for cost savings and personal satisfaction.
  • Professional Services: For larger projects, complex situations, or if you lack the necessary skills, hiring professionals is advisable. They bring expertise and can save time.

Long-Term Maintenance and Care

Maintaining and caring for sealed surfaces is essential for longevity and appearance. Here’s how to ensure long-term care for sealed surfaces:

  1. Regular Cleaning: Keep the sealed areas clean from dirt and debris to prevent wear and tear.
  2. Periodic Inspection: Regularly check for cracks or signs of damage that may need repair.
  3. Use Proper Maintenance Products: Select the right cleaning and maintenance products compatible with sealed surfaces.
  4. Follow Manufacturer’s Guidelines: If specific products were used for sealing, follow the manufacturer’s instructions for care and maintenance.

Latest Trends in Sealants

The world of sealants is ever-evolving, with new materials, technologies, and sustainability considerations shaping the industry’s future. Here’s a look at some of the emerging trends and innovations in sealants:

1. Thermal Interface Materials (TIMs)

WACKER, a prominent player in the sealant industry, has recently opened a global competence center for thermal interface materials (TIMs) in Shanghai, China. This new facility focuses on developing silicone-based thermal interface products for various markets, including electric vehicles, consumer electronics, and telecommunications.

Innovation: Over the past decade, TIMs have been one of the fastest-growing segments globally, with an average CAGR of more than 6%. The demand for silicone-based TIMs is expected to grow continuously as power density increases and thermal management systems become increasingly vital.

Sustainability: Efficient thermal management is essential as electronic devices and batteries generate significant heat, impacting functionality, and service life, potentially leading to serious faults. The industry is turning to heat-dissipation materials for improved thermal management.

2. Bio-Based Materials and Expansion

The industry is also exploring antimicrobial coatings and bio-based materials, reflecting a growing interest in sustainable and eco-friendly solutions.

3. Silicones and General Business Expansion

The expansion of silicones and general business personnel indicates a broader trend towards diversifying products and reaching new markets.


Sealants are essential for bonding and protecting concrete and wood, with the latest industry trends. Innovative materials like thermal interface and bio-based materials offer efficient, eco-friendly solutions. Staying abreast of these trends guides choices and applications, contributing to a sustainable and technologically advanced sealant future.