What are the Types of Caulk & Sealants?

4. What Are The Different Types of Caulks & Sealants in the Market

Manufacturers have not stopped innovating. They have come up with new formations to support specific usage scenarios. Here are some types that high-end manufacturers offer:

Acrylic Latex Caulk

It is the most common and readily available option from your local construction material shop. Acrylic Latex Caulk is a water-based formula. Its composition makes it great for convenient application and cleaning with soap and water. It has a low odor, which makes it suitable for indoor use. Moreover, the surface is highly paintable, making it great for aesthetic projects.

There are variants of acrylic latex caulk that blend silicon, resulting in a higher degree of elasticity for better performance in moderate humidity.

Silicone Sealant

For a sealant that performs the best in challenging outdoor situations, consider silicon. It can handle temperatures from -50 °C to +150 °C without breaking or cracking. While providing excellent resistance against ultraviolet (UV) radiation, its hydrophobic nature keeps biocides and mold away.

Silicon is ideal for strong adhesion between two different surfaces and does not require a primer for proper bonding. The only drawback is that it's not paintable like acrylic latex caulk. It can work on glass, metal, ceramic, and plastic. It comes in two types:

• Acetic: It contains acetic acid, which gives silicone its vinegar-like smell. It's ideal for applications that require fast curing.

• Neutral: For some metals and stones, using neutral material is essential to avoid material damage. These have a low odor. 

Hybrid Polymer Sealant(MS Polymer Sealant)

For advanced formulations, sealant manufacturers have combined the best of silicone and polyurethane materials. It consists of silane-modified polymers (MS chemistry). This mix makes the material highly flexible, providing elongation capability of 300% and allowing 25% joint movement. In comparison to silicone sealant, it provides paintability, giving it the edge over silicone sealant.

As there is no release of gas bubbles and shrinkage, their application is much more convenient for the average user. Hybrid polymer sealants are the most versatile sealants, providing adhesion in marine, automotive, wood, and glass, and perform well on wet substrates. Its key highlight is its high mechanical strength (2.9 MPa) without the chance of staining a surface.

Fire Retardant Sealant

In certain building structures like penetrations across two rooms, walls, or floors, ensuring a fire rating is vital. Fire retardant sealant fills the gaps while preventing the spread of flames, smoke, and fumes. It maintains its integrity in extreme heat conditions and expands to fill spaces that might contain plastics that melt.

For fire-retardant sealant, specialized usage scenarios should be certified with an F-rating or T-rating for passive fire protection. Third-party organizations provide certifications against UL, ASTM, and NFPA standards. These combine strong adhesion with the flexibility required in constructions.

Other Varients:

• Polyurethane (PU) Sealant: For porous substrates like concrete and masonry, PU sealant is ideal. It has strong mechanical strength, elasticity, and excellent adhesion.

• Butyl Rubber Sealant: In case a non-curing, sticky solution for roofing, gutters, and HVAC is required, butyl rubber sealant is ideal. It can hold against air and water.

• Refractory Caulk: Designed specifically for high-heat repairs around furnaces, fireplaces, and chimneys.

5. Buying Considerations for Caulk and Sealant

The general trend in the market is the use of low-VC and eco-friendly products. However, these are not the only things to consider when buying a caulk or sealant to fill the construction gaps.

• Location and Exposure: If the location demands the use of a sealant that can withstand high moisture and UV exposure, then consider silicon or a hybrid polymer.

• Flexibility Needs: For joints that are expected to expand, consider a hybrid polymer or 

• polyurethane.

• Paintability: If you require seamless aesthetics and a sealant that blends with the surrounding, then consider paintable acrylic latex or hybrid polymer.

• Mold/Mildew: The presence of water molecules allows the growth of mold and mildew. Silicon is a naturally hydrophobic material and comes with biocides.

• Adhesion to Surface: For strong adhesion across all materials, use silicon or a hybrid polymer.

• Cleanup Type: For convenient cleaning, use a water-based acrylic latex.

• Certifications: The certifications can depend on the application of caulk or sealant. Typically, low VOCs like GREENGUARD Gold, Indoor Advantage Gold, and Clean Air GOLD are required. For food safety, NSF and FDA standards are common. In the case of performance, ASTM standards like C719 for movement are key.

• Cure Time: For fast curing, always go for a hybrid polymer with VOC and no isocyanates.

6. Recommended Caulk or Sealant based on Application