When sealing round or flat oval ductwork, foam gasket tape is often used to create an airtight seal, maintain energy efficiency, and ensure proper airflow; however, not all foams are created equal. Understanding the difference between open-cell and closed-cell foam is crucial for ensuring a proper seal and avoiding costly mistakes when choosing your materials.

What’s the Difference Between Open and Closed-Cell Foam?

The primary difference between open-cell and closed-cell foam lies in their internal structure.

Open-cell foam has interconnected air pockets, making it highly permeable to air and water. While it's excellent for cushioning or sound absorption, its permeability prevents it from forming an airtight or watertight seal, similar to a sponge. This can lead to air leaks, moisture absorption, and potential mold growth in HVAC systems.

Due to its permeability, open-cell foam is generally not suitable for sealing ductwork. It is more commonly used for projects that require acoustic absorption, padding and cushioning, such as in furniture and bedding, as well as for air sealing where moisture isn't an issue, like in interior walls and attics.

Closed-cell foam, on the other hand, is composed of individual, sealed cells that resemble tiny balloons packed tightly together. This structure makes the foam highly resistant to air and moisture, making it ideal for insulation and sealing. It is also denser and more durable than open-cell foam, resisting compression set, which is the tendency for it to lose its thickness after being compressed.

While both open and closed-cell foam have their uses, closed-cell foam is the clear choice for ductwork because it creates an effective seal by resisting air and moisture, preventing leaks and condensation.

Why is Neoprene Gasket the Best Option for Round & Oval Ductwork?

Among the closed-cell foam gasket options, neoprene is a superior material made from synthetic rubber, ideal for sealing round and flat oval ductwork. Its unique advantages make it the best choice for ensuring a reliable and long-lasting seal.

• Excellent Sealing Properties: Closed-cell neoprene provides a firm, airtight seal, which is critical for preventing air leaks in round and flat oval ductwork. Its ability to conform to irregular surfaces while maintaining integrity ensures a reliable seal.
• Durability and Resilience: Neoprene is highly resilient and resistant to compression set. This means it can withstand the constant pressure and vibration common in HVAC systems without losing its shape or sealing effectiveness over time.
• Flexibility: While durable, neoprene remains flexible, which is essential for creating a tight seal around the curved surfaces of round ductwork. This flexibility allows it to compress evenly around the flanges.
• Clean & Simple Removal: The resilient nature of neoprene foam makes it easy to remove from ductwork without leaving behind a sticky residue or falling apart. This simplifies the process of disassembling ductwork for periodic cleaning or maintenance, allowing for a quick and easy application of new gasket tape to reseal the connection.

Where Can I Buy Ductmate’s Neoprene Gasket Tape?

Ready to buy our neoprene gasket tape?  Ductmate products are available at over 350 locations across the US as part of a selective distribution network.  Use the Ductmate distributor locator map to find a distributor near you.

Outside the US? Check out our international distributor list.  For detailed information on product availability, lead times, or other international sales requests, please email ductmate@ductmate.com.