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 comes from formal education in building science or years of hands-on apprenticeship and work experience. 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 both the substrate and the equipment itself.
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 (who 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.
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 asking solely 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:
What motivates them to perform this work every day?
Why did they get into foam?
How do they know what they say they know?
Who will be on my job, will that person know what they’re doing?
How will we communicate if we move forward; what if my (electrician/plumber/other trade) is not done when you’re scheduled?
Ask for:
References from past customers
Trade references (do they pay their bills, run a good business? Do any contractors in surrounding trades refer them?)
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.
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. The climate the foam is being applied in, matters as well.
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 – Any time, as long as the area is dry.
WHERE CAN SPRAY FOAM BE APPLIED?
Almost anywhere 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.