Open cell or closed cell? Start with the assembly.

Understand the distinction

Open-cell foam has a more open internal structure; closed-cell foam has a denser cellular structure. Closed-cell products generally provide more thermal resistance per inch. Use the actual manufacturer’s product data rather than assuming all foams perform alike.

Check moisture and thickness requirements

Vapor behavior, available cavity depth and the surrounding materials matter. A material described as moisture resistant is not a repair for a leak. Ask the designer or installer how the complete assembly manages water and drying.

Ask for the documentation

Request the product name, technical data sheet, evaluation report and applicable installation instructions. Confirm required coverings, substrate conditions and local approval. A product decision should follow the assembly design, not a blanket rule that one foam is always better.

Keep exploring

What goes into a quote? · Open cell versus closed cell · New construction planning