Is Commercial Spray Foam Roofing Worth It on a Metal Building in Scottsdale?

Yes. Commercial spray foam roofing is one of the best upgrades you can make to a big metal building in Scottsdale. On a building like that, a thin layer of metal is the only thing between the Arizona sun and the space inside. On the job in this video, foam on the top side of the roof took the underside from 120 to 135 degrees down to about 85 to 95 degrees.

This building is basically a big metal barn. Before we got there, the roof was bare sheet metal soaking up sun all day and passing that heat straight down. In the video my crew says it plainly: "The underside was reaching temps from 120 to 135. Now that we got the foam on the roof, we're seeing temps anywhere from about 85 to 95 degrees, depending on how hot it is."

I'm Mikel Wallesen, owner of Big Red Roofing. I took this business over from my father, and we've been Scottsdale roofers since 1987. Here's why we foam the top side of big commercial metal roofs, what the reflective coating does, and why the energy efficiency adds up.

Why does a big metal commercial building get so hot under the roof?

A big metal commercial building gets hot because the roof is often just a thin layer of metal with no real insulation on top. Metal takes on heat fast and passes it straight through to the space below.

Look at the building in this video. It's a large metal structure, like a barn or a warehouse, and the roof was bare panels and nothing more. The Arizona sun hits that metal all day and the heat goes right through. That's how the underside got up to 120 to 135 degrees. A thin sheet of metal doesn't slow heat down. It hands it off.

The usual mistake on these buildings is treating the roof as only a rain cover. Owners add cooling equipment, run fans or put up with the heat, and the roof stays the same. On a big commercial building, that means paying to cool a huge space while the roof keeps loading it with heat. If you own or manage one of these buildings, ask what is actually on top of that metal. Often the answer is nothing.

Why do we put spray foam on the top side of a commercial metal roof?

We put spray foam on the top side because the sun hits there first. As my crew put it, "Having the spray foam on the top side of the roof limits the heat from transferring through the roof. So the foam adds as your insulation."

The idea is simple. Stop the heat before it gets into the metal, not after it has come through. Foam sprayed across the top of the roof forms one continuous layer of insulation with no seams or gaps for heat to slip through. On a big commercial roof with a lot of panels and fasteners, that matters. You aren't piecing together insulation. You're covering the whole surface in one layer.

Some contractors try to solve the heat from underneath and leave the top alone. That helps a little, but the metal still bakes all day. If you're comparing bids, ask each contractor where the insulation is going and why. On a big metal building, I want it on top, where the heat starts. I wrote more about how top-side spray foam insulation lowers metal roof temperatures.

How much cooler did the underside get on this metal building?

On this job, the underside of the roof went from 120 to 135 degrees down to about 85 to 95 degrees after the foam went on. That's a drop of roughly 35 to 40 degrees on a building that had only bare metal before.

Those numbers came from this roof, not a brochure. Before the foam, the crew saw the underside reach 120 to 135. After the foam, they saw about 85 to 95, "depending on how hot it is." Compare the ends of each range and the underside is running roughly 35 to 40 degrees cooler.

Pay attention to the words "depending on how hot it is." No roof sits at one exact temperature every day. What matters is that the whole range dropped. If a roofer promises one fixed number for every day of the year, be careful. Real roofs react to real heat, and an honest contractor gives you a range. For more on metal, see does spray foam work as insulation on a metal roof.

What does the reflective coating do on a commercial spray foam roof?

The reflective coating that goes over the foam bounces the Arizona sun off the roof. The foam slows the heat that gets in, and the coating cuts down how much heat the roof takes in to begin with.

The two layers work together. The coating is the first thing the sun hits, and it sends a lot of that sunlight back off the roof. Whatever heat gets past the coating still has to get through the foam. On a big commercial building in Scottsdale, a large roof surface takes a lot of sun every day, so both layers count.

Treating the coating as an afterthought is a mistake. The foam is the insulation, but the coating is what faces the sun. Ask any contractor what coating goes over the foam and what it's for. I cover the coating side in how professional roofers protect metal spray foam roofs with base coats and glare control.

Does commercial spray foam roofing pay off in energy efficiency?

Yes. On a big commercial building, energy efficiency is where spray foam earns its keep. A roof that lets far less heat through means the building isn't fighting that heat every day, and the savings add up over the years.

Go back to the numbers. With an underside at 120 to 135 degrees, that heat goes straight into a large space you're trying to keep cool. Bring it down to about 85 to 95 and the cooling has much less to deal with. On a big metal building the size of a barn, that difference adds up across all that square footage, every summer the building stands.

The cost of doing nothing is easy to miss because it never shows up as one bill. It shows up a little at a time, year after year. Owners who only compare the up-front cost of roofing options miss that. Ask any roofer how the roof will perform over the years, not just on the day the crew leaves. For your own building, our pricing page and estimator are the place to start.

Is spray foam the right fit for every Scottsdale roof?

No. Spray foam shines on big commercial buildings, especially metal ones where a thin layer of metal is the only thing keeping out the heat. Other roofs, like the clay tile roofs on many Scottsdale homes, need a different approach.

The building in this video is the best case for foam: a large metal roof with nothing on top, taking full sun. A lot of the homes we work on are tile, and those jobs are about underlayment and tile work, not foam. Matching the roof system to the building is the whole job.

Be wary of anyone who pitches the same product for every roof. A good roofer looks at the building first: what it's made of, how big the roof is, and what the heat is doing to it. To see how foam behaves on this kind of building, read what happens when you spray foam a metal roof and what happens when you foam a metal roof in Phoenix.

What should you ask a roofer before spray foam goes on a commercial roof?

Ask what the foam and coating will do about the heat, and how they'll show you it worked. A good roofer should talk about real temperatures before and after, not just make promises.

We can do that because we took actual readings on this metal building. An underside at 120 to 135 degrees became about 85 to 95. That's the kind of before and after you should expect a contractor to talk about. If a roofer can't explain why foam goes on the top side, or what the coating does, keep asking.

Ask about the whole system, not only the foam. Where is the insulation going? What coating goes over it? How will the roof hold up in the sun over time? A sales pitch with no explanation is a red flag. On a big commercial roof, getting it wrong means years of extra heat and energy use.

What happens when you call Big Red Roofing about your project?

When you call Big Red Roofing at 602-799-6837, you're talking to a family-owned, owner-led roofing company that has been in Scottsdale since 1987. We start with your building and what the heat is doing to it, and we give you straight answers.

We grew on word of mouth and referrals, so we treat every call like a referral. We're Licensed AZ ROC #276008 with a BBB A+ rating. Read more about us or about me, Mikel Wallesen. For metal and commercial buildings, see our commercial roofing and spray foam roofing pages, commercial spray foam roofing in Scottsdale and our Scottsdale service area page.

The quickest first step is our estimator, and our pricing page explains how we approach cost. When we talk, I'll want to know how big the building is, what the roof is made of and how hot it runs underneath. We also serve nearby cities including Phoenix, Paradise Valley, Fountain Hills, Tempe and Mesa.

Frequently asked questions: what else do Scottsdale, Arizona homeowners want to know?

How much does commercial spray foam roofing cost in Scottsdale?

It depends on the building, especially the roof size and what's on it now, so I won't put a number here. Start with our estimator and pricing page. On a big commercial building, also weigh long-run energy efficiency, not just the up-front cost.

How long does a spray foam roof take on a commercial building?

That depends on the size and condition of the roof. A big metal building is a different job from a small one. Reach out through our contact page and we'll talk through what your Scottsdale job involves.

What does spray foam actually do on a metal roof?

It works as insulation on the top side of the roof, limiting heat moving through the metal, and a reflective coating over it bounces the sun off. On the metal building in this video, the underside went from 120 to 135 degrees down to about 85 to 95.

Are there alternatives to spray foam roofing?

Yes. We also do tile roofing, including underlayment replacement and full tear-off, along with shingle roofing and commercial and metal roofing. On a big metal commercial building, spray foam roofing is where I see the biggest difference.

How does spray foam handle the Arizona heat in Scottsdale?

Heat is the reason we use it on big metal buildings. The foam limits heat moving through the roof, and the reflective coating bounces sunlight off. The readings from this job came from a roof working in real Arizona heat, and your results will depend on your building and the weather.

What maintenance does a commercial spray foam roof need?

The coating faces the sun every day, so it's the part to keep an eye on. I won't guess at a schedule that doesn't fit your building. Ask us about upkeep when we look at your Scottsdale project.

How do I get started with Big Red Roofing?

Call us at 602-799-6837, use our contact page, or start with the estimator. Tell us about your building, the roof and the heat you're dealing with, and we'll take it from there.