FAQ
WHY IS SPRAY FOAM SO EXPENSIVE?
Our short answer to this common question is that, in life, just about everything costs the same in some way, shape, or form. In other words: “you get what you pay for.” Spray foam is expensive to produce compared to other commonly used insulation products. It’s essentially manufactured on the spot—on a job site, in our rigs—which are far more complex and costly than the staplers, tapes, and hammers used for traditional insulation.
The expertise required is expensive too—whether it’s hired, comes from formal education, or results from years of hands-on apprenticeship. Spray foam rigs usually run diesel engines, so maintenance requires either hiring an experienced diesel mechanic or having that knowledge yourself.
It also takes a solid understanding of how buildings work—how air moves, how moisture is controlled—because spray foam doesn’t just insulate; it seals. That means you’re dealing with both building science and the chemical manufacturing science happening in the rig during application. Foam quality depends on the temperature and moisture of the substrate, the surrounding air, and the equipment itself.
Knowing when and where to apply the foam entails a scientific understanding of how weather affects each substrate differently. How the technician applies foam to a pole shed in August is different than in November, depending on the geographic area. In some climates, it’s ill-advised to apply spray foam to metal substrates especially on a ceiling with snow on the roof. At exterior temperatures under 20°F, an experienced foamer may be able to accommodate lower temperatures when dealing with metal, using creative solutions and extra time—all of which cost.
With all that in mind, spray foam ends up doing four times more work for a building than any other product in it. It’s the only product that can actually pay you back over time. Choose shingles or a metal roof, and you won’t see monetary dividends. Even “energy-efficient” appliances often cost more in the long run due to planned obsolescence—cheap plastic parts, hard-to-repair designs, etc. But foam?
Foam saves you money by:
Strengthening the structure (it literally glues it together)
Helping deter mice and bugs (which cause damage inside walls)
Blocking air and moisture flow (which reduces potential damage and improves air quality)
Reducing strain on heating and cooling systems (lower bills, reduced carbon footprint, longer equipment life)
No other building product offers these returns. Yes, it’s more expensive upfront—but it saves you time, money, and headaches down the road... when applied correctly. So is it really expensive? No. It’s the standard that insulation—and building performance in general—should be held to.
ARE THERE GOOD AND BAD FOAM CONTRACTORS, AND HOW DO I KNOW THE DIFFERENCE?
YES. Just like half of all doctors graduate in the bottom half of their class, some contractors simply aren’t very good. You wouldn’t stick with a doctor who felt “off,” and this is no different.
As for knowing the difference—it’s a hard pill, but it’s on you. You’re not just asking for a price; you’re inviting someone into your space, so treat it like an interview. You don’t need to understand foam—you need to understand them.
Ask anything:
Why did they get into foam?
What’s their background prior to foam work?
Who will be performing the actual work, and what is their knowledge base?
Ask for:
References from past customers
Trade references (do they pay their bills, run a good business?)
Official business name to look up longevity in business (state corporate records site) and any circuit court activity
Look them in the eye. Gauge their transparency and professionalism. Read their Google reviews, but use discernment—some reviews (good and bad) can be fake. Look for discrepancies, such as reviews that reference a different business name; this is a red flag of past rebrands worth checking on circuit court records.
And if you still run into trouble? Don’t beat yourself up. There are folks like us with decades of experience ready to help fix it. No judgment. It’s tough out there. Sometimes the best guy turns out to be the lowest price, sometimes he’s not. Price isn’t always the best gauge.
IS SPRAY FOAM INSULATION WATER RESISTANT?
YES – but only when using closed-cell foam at 2 inches or more.
NO – if less than 2 inches of closed-cell, or any amount of open-cell foam.
WILL SPRAY FOAM SEAL OUT BUGS?
YES – spray foam eliminates air leaks, which bugs use to locate entry points.
WILL CRITTERS LIKE MICE, SQUIRRELS, AND BATS EAT THROUGH FOAM?
They can, but they’re much less likely to. Just like bugs, these critters are drawn to airflow and leaky spots—which spray foam eliminates. Most will move on and look for easier entry points elsewhere.
WILL SPRAY FOAM EVER DISINTEGRATE?
Yes, it can degrade in sunlight. That’s why foam should be covered with drywall, OSB, or paint as soon as possible to protect your investment.
WILL SPRAY FOAM CATCH FIRE?
No—it won’t ignite, but it can melt. A fire-retardant barrier can be applied after spraying. This doesn’t stop fire but buys up to 15 minutes of extra time.
WHEN IS THE BEST TIME TO SPRAY/INJECT FOAM IN MY HOUSE?
Anytime temperatures are above 40°F is ideal for any foam application.
Scenarios:
New construction – Before or after windows, as long as the roof is up.
Remodels – Outside: above 40°F. Inside: anytime, assuming the rig has heated hoses.
Attic conversions or basement box sills – Anytime, as long as the area is dry.
Metal sheds – No snow, no moisture; temperature and dry heat are important, plus special measures are needed depending on many factors.
WHERE CAN SPRAY FOAM BE APPLIED?
Almost anywhere that’s dry with a clear spray line. It’s applied with a high-pressure gun, like large-scale paint equipment.
CAN YOU SPRAY FOAM MY CRAWL SPACE?
YES – spray foam is a great permanent solution for sealing tight crawl spaces where traditional insulation fails over time.
SPRAY FOAM LOOKS LUMPY IN SPOTS – DOES THAT AFFECT PERFORMANCE?
Foam can look lumpy depending on what it’s sprayed onto. Smooth foam happens on flat surfaces like poured concrete. Lumps show up on uneven substrates (like ribbed steel, corners, old framing). What matters is that:
The foam seals what needs to be sealed
The overall depth meets or exceeds the estimate
At Rock Road, we aim to apply what we quoted—or a bit more.
IS SPRAY FOAM TOXIC?
Briefly. Only while being applied and up to 48 hours while it off-gasses.
HOW LONG DO I NEED TO AIR OUT MY HOUSE?
24–48 hours, depending on your home’s airflow.
CAN WE STAY IN THE HOUSE THE SAME NIGHT?
No. People and pets should leave during installation. Return time depends on temperature, humidity, and foam type. Ask your applicator for guidance.
IS SPRAY FOAM FLAMMABLE?
Only during application. Once cured, it is not flammable.
WHAT KIND OF ENERGY SAVINGS CAN I EXPECT?
At least 30% on energy bills using 2 inches or more of closed cell foam in high-loss areas.
WILL SPRAY FOAM LOSE ITS R-VALUE OVER TIME?
Very slightly. Some studies show a small drop over the years—but it’s far less than traditional insulation, which loses R-value much faster. For more, check out “The R-Value Fairy Tale” on our resources page.