Level Up Insulation Co.

All Resources

The Pros and Cons of Spray Foam Insulation: A Complete Guide

Spray foam insulation expanded inside wall cavities showing air barrier and high R-value benefits evaluated by Level Up Insulation Co. for Denver homeowners
We install spray foam insulation across Colorado. We believe it’s the highest-performing insulation product available — and we also tell homeowners when it isn’t the right choice for their specific situation. Here is an honest assessment.

The Pros of Spray Foam Insulation

1. It Insulates and Air-Seals in a Single Application

Every other insulation product — fiberglass batts, blown-in insulation, mineral wool — provides thermal resistance only. Spray foam does both: it resists heat transfer and it physically blocks air movement. Since air leakage accounts for 25–40% of heating and cooling costs in most Colorado homes, this dual function is what makes spray foam uniquely effective.

2. Highest R-Value Per Inch

Closed-cell spray foam delivers R-6 to R-7 per inch — more than double the R-value per inch of fiberglass batts or blown-in cellulose. This matters in tight spaces: rim joists, narrow rafter bays, and cathedral ceilings where you can’t add depth. Open-cell spray foam delivers R-3.5 to R-4 per inch, which is comparable to blown-in but with the added air-sealing benefit.

3. Lifetime Durability

Properly installed spray foam does not settle, compress, sag, or degrade. It maintains its R-value for the life of the structure — 40, 50, 60+ years. Blown-in cellulose settles 15–20%. Fiberglass batts compress when improperly installed or disturbed. Spray foam stays where it’s put.

4. Moisture Resistance (Closed-Cell)

Closed-cell spray foam is both an air barrier and a vapor barrier. It does not absorb moisture, does not support mold growth, and physically prevents water vapor from passing through. This makes it the correct choice for crawl space encapsulation in Colorado, basement rim joists, and any below-grade application.

5. Structural Contribution

Closed-cell spray foam adds meaningful structural rigidity to wall and roof assemblies. Studies document increases in wall racking strength of up to 300% with closed-cell foam in wall cavities. This is especially relevant for older Colorado homes where framing has experienced some settling.
Need Help with Your Insulation Project?

Contact us today for a free consultation and estimate.

The Cons of Spray Foam Insulation

1. Higher Upfront Cost

Spray foam costs 2–4x more per square foot installed than blown-in insulation in Colorado or fiberglass batts. For a standard attic, this can mean $4,000–$8,000 for spray foam vs. $2,000–$4,000 for a blown-in plus air sealing package. The spray foam often pays back faster due to better performance, but the upfront cost is a real barrier for some homeowners.

2. Installation Quality Is Critical

Spray foam is applied by mixing two chemicals at a specific ratio, temperature, and thickness. If any of those variables are wrong — the ratio is off, the temperature is too cold, the thickness per pass is too great — the foam can cure soft, shrink, or fail to achieve rated R-value. This is not a DIY-friendly product and not a product where you want the cheapest contractor. A bad spray foam job is worse than no job because it’s expensive to fix.

3. Permanent Bonding Makes Future Access Harder

Spray foam bonds permanently to every surface it contacts. If you need to add electrical wiring, run new plumbing, or access structural members in a wall or attic where spray foam was installed, you’re cutting through cured foam — which is messy and time-consuming. This isn’t a reason not to use spray foam, but it’s a reason to think carefully about future access needs before application.

4. Not Always the Right Tool for Attic Floors

For attic floor applications where the goal is simply adding R-value on top of existing insulation, blown-in insulation combined with attic air sealing is often the better value than spray foam. The combination delivers 85–90% of spray foam’s energy performance at significantly lower cost. Spray foam on the attic floor makes sense when you’re converting to a conditioned attic assembly — not simply adding R-value.

5. Temporary Occupant Disruption During Installation

During application, spray foam produces fumes that require ventilation and temporary avoidance of the installation area. For sensitive occupants (pregnant women, infants, people with respiratory conditions), a full-day absence from the home is recommended. Once fully cured — within 24 hours — spray foam is inert and non-toxic.

When Spray Foam Is the Right Choice

  • Rim joists and band joists — closed-cell spray foam is the best product for this application, period
  • Crawl space walls and encapsulation — see crawl space encapsulation in Colorado
  • Cathedral ceilings and roof deck applications for conditioned attic assemblies
  • Metal buildings, garages, and pole barns where moisture control and structural contribution matter
  • Homes where maximum air sealing performance is the priority over cost

When Spray Foam Is Not the Right Choice

  • Adding R-value to an attic floor where existing insulation is in good condition — blown-in insulation in Colorado is better value here
  • When budget is the primary constraint and the home needs basic R-value improvement more than air sealing
  • When the project timeline doesn’t allow for occupant relocation during curing
  • Walls in existing homes where drywall would need to be removed — injection foam or blown-in dense-pack is better for retrofit wall applications

Ready to Fix It? Get a Free Free Spray Foam Assessment Estimate

Level Up Insulation Co. is BPI certified, an Xcel Energy rebate partner, and serves the entire Colorado Front Range. Call us or request your free estimate online — we assess your home, explain every option, and give you a clear quote with no hidden fees and no pressure. Schedule online at Free Spray Foam Assessment

Get a Free Quote


We'll respond within 24 hours

This will close in 0 seconds