HS Code for Caulk

Caulk is classified under HS code 3214.10, which covers mastics, painters' fillings, and similar non-refractory surfacing preparations. This classification is appropriate because caulk is a material used to seal joints or seams against leakage in various structures and piping. These products are typically based on polymers like silicone, polyurethane, or acrylic resins, mixed with fillers and pigments. The primary function is to fill gaps and provide a flexible or rigid seal, which aligns perfectly with the definition of mastics and painters' fillings in the Explanatory Notes to Chapter 32. Whether the caulk is used for residential windows or industrial piping, its chemical composition as a filler or mastic dictates its placement in this specific subheading.

Products Included

• Silicone sealants and caulks
• Acrylic latex caulk
• Butyl rubber caulk
• Glazier's putty
• Resin-based joint fillers

Common Misclassification

Frequently confused with 3506.91 (adhesives based on polymers) because some caulks have adhesive properties. However, if the primary purpose is filling or sealing rather than bonding two surfaces, 3214.10 takes precedence. It is also sometimes misclassified under 3214.90, which is reserved for other surfacing preparations like non-refractory plastering materials.

FAQ

What is the HS code for caulk?

The standard HS code for caulk and similar mastics is 3214.10.

Is silicone sealant always 3214.10?

Yes, if the silicone is formulated as a mastic or filler for sealing gaps, it falls under 3214.10. If it is a pure silicone polymer in primary form, it would fall under Chapter 39.