The Science Behind Spray Foam Insulation: How It Expands and Seals

Spray foam insulation has become one of the most effective ways to insulate homes and commercial buildings. But what makes it so efficient? The secret lies in the fascinating science behind how spray foam expands and seals.

When spray foam is applied, two liquid components—polyol resin and isocyanate—mix together at the tip of the spray gun. This chemical reaction causes the mixture to rapidly expand, often up to 30–60 times its original volume. As it expands, the foam fills cracks, gaps, and hard-to-reach spaces that traditional insulation materials can’t cover.

Once it hardens, spray foam creates a continuous air barrier that prevents heat loss, reduces drafts, and blocks moisture infiltration. This airtight seal not only enhances comfort but also improves energy efficiency—helping you save significantly on heating and cooling costs year-round.

There are two main types of spray foam insulation:

• Open-cell foam, which is softer and ideal for soundproofing and interior spaces.
• Closed-cell foam, which is denser and offers higher R-values and moisture resistance—perfect for exterior walls, basements, and attics.

At Custom Insulation Company, Inc., our team uses high-quality spray foam materials and proven installation techniques to ensure long-lasting results and maximum energy performance. Whether you’re building new or upgrading your existing insulation, we can help create a more efficient and comfortable environment.

Contact Custom Insulation Company, Inc. today to learn more about how spray foam insulation works and why it might be the best choice for your property.