Understanding Sealants: Types and Application Techniques

Sealants play a crucial role in keeping your property protected from water damage, drafts, and other environmental elements, ensuring durability and efficiency. Gaps, cracks, and joints can develop over time, and these create pathways for water to seep through, causing potential damage. Sealants fill these vulnerabilities by creating a watertight barrier that prevents leaks and infiltration. 

If you are a homeowner looking to build a house, knowledge regarding sealants is important, as they are essential for protecting your home. 

Types of Sealants

There are several types of sealants, each with unique properties and ideal applications. The following are the most common ones that will help you choose the right option for your project. 

Silicone Sealants

Silicone sealants are formulated with silicone polymers. They are ideal for dynamic joints, as they can accommodate significant movement. Silicone also bonds well to various kinds of surfaces including concrete, metal, glass, and most common building materials. Silicone sealant is very appropriate for your property as it can withstand harsh weather conditions like sunlight, rain, and extreme temperatures. Silicone sealing is perfect for sealing joints that experience movement such as around showers, tubs, sinks, during bathroom waterproofing. The sealants also work for countertops, expansion joints in concrete, window and door perimeters. 

It is important to note that not all silicone sealants are paintable. It is advised to check the manufacturer’s instructions if painting is desired. 

Polyurethane Sealants

Polyurethane sealants are renowned for their strength and durability, available in both flexible and rigid formulations. They offer excellent resistance to abrasion, chemicals, and harsh weather conditions, making them highly versatile for various waterproofing tasks such as flat roof waterproofing, decks, balconies, plazas, and sealing around chimneys and skylights. Polyurethane sealants are also suitable for below-grade waterproofing, depending on the specific type. However, they can emit strong odors during application and may have longer curing times compared to silicone options.

Polysulphide Sealants

Polysulphide sealants are high-performance sealants known for their exceptional elasticity, durability, and resistance to harsh conditions. Made from liquid polysulfide polymers, they cure to form a rubber-like material with superior flexibility, allowing them to accommodate significant movement and expansion in joints. These sealants exhibit excellent durability, with resistance to weathering, UV rays, and a wide range of chemicals, making them ideal for long-term exterior applications. They bond well to various surfaces, including concrete, masonry, metal, wood, and glass, and offer excellent water and chemical resistance. Polysulphide sealants are particularly suited for expansion joints in concrete, roofing applications, building envelopes, below-grade waterproofing, and marine environments.

Steps Involved in Applying a Sealant

Surface Cleaning

Ensure the surface is clean, dry, free of dirt, dust, debris, grease, and any existing sealant. Use a wire brush or stiff broom for initial cleaning. For stubborn grime, a degreaser or rubbing alcohol might be necessary.  A clean surface allows for optimal sealant adhesion.

Crack and Gap Management

For larger cracks exceeding ¼ inch width, consider using a backer rod made of foam or polyurethane. This fills the void efficiently, allowing the caulk to form a better bond and bridge smaller movements more effectively. Backer rods prevent the sealant from overfilling the gap and becoming too thin, which can compromise its waterproofing ability.

Masking for a Clean Finish

For a professional look, apply masking tape along the edges of the joint to create a defined line for the caulk bead. This helps achieve clean lines and minimizes cleanup afterward.  Press the masking tape firmly to ensure the sealant doesn’t seep under it.

Cutting the Caulk Tube Nozzle

Use a utility knife to cut the nozzle at a 45-degree angle with an opening slightly larger than your desired bead size. A larger opening can lead to excessive sealant use and potential mess, while a smaller opening might make application difficult.

Applying the Caulk Bead

Hold the gun at a 45-degree angle and apply the caulk steadily along the joint in a continuous bead, ensuring good contact with both sides of the joint. Maintain consistent pressure for a uniform bead size.  A smooth and uninterrupted bead is crucial for proper waterproofing.

Tooling the Bead

Use a wet caulking tool (like a smoothing tool) to smooth and shape the bead for a clean and professional finish.  Wetting the tool prevents the sealant from sticking to it and allows for easier shaping.

Cleaning Up Excess Sealant

Wipe away any excess caulk on the surrounding area with a damp rag before it dries.  Act quickly to prevent the sealant from becoming difficult to remove.

Curing Time

Allow the caulk to cure completely as per the manufacturer’s instructions.  This typically takes 24-48 hours for most caulks. Don’t test the seal or apply stress to the area until it’s fully cured.

Sealants are an integral part of the waterproofing process. The process should be carried out carefully, without missing any detail. Sunanda Global, the best waterproofing company in India, offers comprehensive waterproofing solutions utilizing all the integral techniques and materials necessary to ensure the durability and quality of your property. We have diverse products that can cater to multiple industries such as epoxy paint, waterproofing admixture, polyurethane coating, etc.