Loctite^® Caulk and Sealant Selection Guide

Caulk vs. Sealant

Caulk and sealant serve to seal joints and fill gaps between materials, making these terms interchangeable. While they create a barrier against moisture, sound, dust, and other elements, they differ in elasticity.

Caulks, typically made from latex and acrylic, provide a tight hold when sealing fixed surfaces and are primarily used to fill construction cracks. However, silicone-based sealants are more flexible than caulks and are better suited in spaces with fluctuating temperatures.

When selecting a filling, you need to consider how and where you will use it. If the job requires binding two surfaces together, select a sealant. If you are filling in gaps, use a caulk. Finally, if the job is outdoors or in a room with changing temperatures, select a silicone sealant.

Applications

The two common types of applications are weatherproofing and structural, also known as glazing.

Weatherproof sealants can create an adequate barrier that offers UV protection and prevents moisture and water from entering the structure. For this form of application, it's essential to consider the following:

• Adhesive strength
• Joint movement – seismic movement, shrinkage, material temperature, and moisture-induced movement
• Sealant movement capability – the amount of movement the filling can accept from its original cured joint width
• Installation guidelines – found in ASTM C1193 (Standard Guide for Use of Joint Sealants) and manufacturer instructions

Structural sealants are load-bearing and can reinforce, anchor, bond, and repair materials. For this form of application, consider the following:

• Bite – the area where the filling on the panel meets the frame to support weight transfer
• Thickness – the space required by the filler between the panel and frame to facilitate the installation and to reduce stress on the joint caused by thermal movement
• Dead load – the weight a panel places on the sealant joint
• Installation guidelines – found in ASTM C1401 (Standard Guide for Structural Sealant Glazing) and manufacturer instructions

User Tips

Here are some storage, preparation, and application tips to follow for proper installation:

• Store building material preferably in an enclosed space away from any damaging elements.
• Store in a cool, dry place to avoid shortening shelf life and causing premature curing due to extreme temperatures and moisture.
• Clean and dry the surface area before applying. Dust, dirt, grease, or moisture (e.g., ice, snow, and frost) will interfere with adhesion if not removed beforehand.
• Use steady pressure when applying it to the joint. This tactic ensures adequate and even bonds to both substrates and avoids irregular bead shapes. A caulking gun is best for an easy application.
• Clean the tools used during the application with appropriate solvents before the caulk dries.