As energy regulations tighten, technology improves, and homeowners demand better energy performance from their homes, insulation has become more than just an afterthought; it’s an essential component of efficiency, comfort, and long-term durability.
At Custom Insulation, we’re proud to offer closed-cell spray foam insulation as part of our comprehensive service lineup. Whether you’re planning a new build, a remodel, or a retrofit, knowing your insulation options will help you make the decision that will best protect your investment. Read on to find out what spray foam is, how it works, and why it’s one of the most advanced insulation solutions on the market today.
What Is Spray Foam Insulation?
Spray foam insulation is a two-part liquid compound—typically polyurethane—applied to surfaces as a spray. Upon contact, it rapidly expands and hardens into a dense foam. There are two types: open-cell and closed-cell. At Custom Insulation, we specialize exclusively in closed-cell spray foam due to its superior thermal performance and structural integrity.
Closed-cell spray foam consists of tightly packed cells filled with a blowing agent that enhances thermal resistance. It forms a rigid, air- and moisture-impermeable barrier, making it highly effective for insulating and air-sealing building envelopes in a single application. With an R-value of approximately 6.5 to 7.0 per inch, it outperforms nearly every other commonly used insulation material. Think of it as a snug, waterproof jacket for your home.
How It Works and Why It Matters
The performance of spray foam relies on both its material properties and the skillfulness with which it is applied. Because the foam is deployed as a liquid, it conforms precisely to the shape of the cavity, filling irregular gaps, seams, and voids that traditional batts or other insulation materials often miss. This results in a continuous insulation layer with minimal thermal bridging and near-complete air sealing.
Closed-cell spray foam provides several performance advantages:
- Energy efficiency: Closed-cell spray foam boasts one of the highest R-values per inch in the insulation world. Translation: it keeps heat in during the winter and out during the summer with impressive efficiency.
- Moisture resistance: Because it forms a rigid, water-resistant barrier, it can help prevent mold and mildew—two things nobody wants lurking behind their drywall. This is a particularly useful quality in mixed-humidity climates like North Idaho and Eastern Washington.
- Longevity: Spray foam doesn’t sag, settle, or degrade over time. You install it once, and it keeps working for decades.
- Air barrier properties: It reduces uncontrolled air infiltration and exfiltration, both major sources of energy loss in buildings.
- Structural enhancement: The hardened foam adds shear strength to wall assemblies, which is beneficial in high-wind or seismically active regions. It can increase a wall’s racking strength by up to 300%!
- Deters pests: Closed-cell spray foam insulation creates a dense, seamless barrier that insects and rodents can’t chew through or nest in, effectively sealing off common entry points.
Thermal imaging, which we use on every spray foam project, allows us to verify consistent coverage and locate any potential weak spots in the envelope before the job is complete. Using a special lens, our camera captures an image of your home or building and lights up areas where heat is escaping.
Ideal Applications and Considerations
Closed-cell spray foam is particularly well suited for:
- Attics, crawl spaces, and rim joists, where air leakage is common and access is limited
- Wall cavities in new construction, where spray foam can be installed quickly and precisely before drywall installation
- Retrofit projects, where sealing existing gaps can drastically improve performance without removing large portions of the structure
While spray foam may cost more upfront than fiberglass, rockwool, or cellulose, the energy savings over time make up for it. It’s not just an upgrade; it’s an investment in long-term comfort and performance.
We won’t pretend it’s the perfect fit for every situation. If you’re insulating a structure where breathability is crucial, or you’re on a shoestring budget, other options might be worth exploring. That said, for most residential and commercial applications where efficiency, air sealing, and moisture resistance matter, closed-cell spray foam is hard to beat.
Our team at Custom Insulation will assess each project to determine the right balance of performance, budget, and building science considerations are best for you. We never apply a one-size-fits-all solution; every recommendation we make is grounded in over two decades of hands-on experience across residential and commercial job sites.
Let’s Build Smarter
Spray foam insulation represents the future of high-performance building, combining insulation, air sealing, moisture control, and durability in a single application. When installed properly, it significantly improves the energy efficiency and indoor comfort of a home or commercial structure.
At Custom Insulation, we take pride in offering closed-cell spray foam services backed by rigorous standards, cutting-edge technology, and a deep understanding of building systems. If you’re considering spray foam for your next project, we invite you to visit our website to learn more or schedule a consultation with our expert team. We want to help you find the insulation solution that’s perfect for your home or business!