Differences Among Silicone, Adhesive and Caulk

Silicone is a material that is found in adhesives, caulk and sealants. The properties that make silicone suitable for these uses include its ability to create watertight seals. The material does not yellow over time and has high resistance to oxygen, ozone and UV light. Other properties of silicone that make it a popular choice include its adhesion capabilities and ability to flex, making it long-lasting and mold and mildew resistant.

Adhesives are materials that bond two surfaces together, preventing the surfaces from moving. Adhesives are made out of many different materials that are specifically designed for the job. For example, substances made out of cyanoacrylate, also called Super Glue or Krazy Glue, will create a bond between two unlike surfaces. Factors to be considered when selecting adhesives include surface type, how the materials are prepared, the environment the adhesives will be exposed to and the strength of the bond.

Caulk is used to fill in joints or cracks between spaces. The purpose of caulk is to seal these areas from water, dust, pollen and even noise. A good caulk will have strong adhesion to both surfaces it is touching, will not crack and last for a prolonged period of time. The joints or cracks that caulk covers may move, and caulk needs to have some elasticity to be able to account for this movement without failing. Adhesives' goal is to prevent movement of surfaces, making it different from caulks.

Sealants and caulk terms are commonly used interchangeably. However, while the application of a sealant and caulk is typically the same -- through a caulking gun -- sealants are higher performance caulk. Caulk has some elasticity to move along the joint to keep the gaps filled in; however, caulks have lower elastometric properties than sealants. Elastometric means that a sealant can stretch when placed under pressure and will return back to normal size when the pressure is removed.