If your commercial building in the Phoenix area has an aging metal roof, you already know the trade-offs: metal panels are durable and low-maintenance, but they aren’t great insulators. Heat moves right through the panels, seams and fasteners are common leak points as the roof ages, and cooling costs in the Phoenix heat can add up fast.
The good news is you don’t have to tear the whole roof off to fix this. One of the most effective upgrades we install is a recover system: plywood decking installed directly over the existing metal panels, followed by a spray polyurethane foam (SPF) roofing system. It transforms an inefficient metal roof into a smooth, insulated, seamless membrane — without the cost and disruption of a full replacement.
What Is a Spray Foam Over Metal Roof Recover System?
A metal roof recover system upgrades your existing roof in two steps: installing a plywood deck over the metal panels, then applying a spray polyurethane foam (SPF) roofing system on top. It’s one of the most cost-effective ways to improve commercial metal roof insulation without a full replacement.
Step 1: Plywood Over the Existing Metal Panels
Standing seam and corrugated metal roofs have ribs, seams, and exposed fasteners that make it difficult to apply foam evenly. Before any foam goes down, our crews install OSB plywood decking across the entire roof, screwed directly into the metal substructure.
This does two things:
- Creates a flat, uniform surface for the foam application, instead of foam having to bridge over ridges and valleys in the metal
- Adds a structural layer that strengthens the existing roof assembly and gives us a clean base to work from
You can see this stage in our own project photos — plywood sheets laid edge to edge over the metal roof panels, with the underlying rib pattern still visible beneath the boards before the deck is fully covered.
Step 2: Spray Foam Roofing System Improves Insulation and R-Value
Once the plywood deck is complete, we apply a spray polyurethane foam (SPF) roofing system directly over it, finished with a protective elastomeric coating and granules or coating for UV protection and walkability.
This is where the real efficiency gains come in. Closed-cell spray foam typically provides somewhere in the neighborhood of R-6 to R-7 of insulation value per inch, depending on the specific foam product and density. So even a modest 1″ application meaningfully boosts the roof’s total insulating capacity — something a bare metal panel roof simply doesn’t offer on its own.
Beyond the R-value, foam roofing has a few other advantages worth mentioning:
- Seamless, monolithic membrane — no seams or laps for water to find its way through
- Self-flashing around penetrations — foam conforms around vents, curbs, and rooftop equipment instead of relying on separate flashing details
- Renewable, not replaceable — when it’s time for maintenance down the road, the foam and coating can typically be recoated rather than torn off and replaced
- Reflective finish — the white coated surface reflects sunlight instead of absorbing it, which helps reduce rooftop and interior temperatures
Why This Matters for Building Owners
For a building owner, the payoff shows up in a few places:
- Lower cooling costs — added insulation and a reflective surface both reduce heat gain
- Fewer leaks — eliminating seams and exposed fasteners removes the most common failure points on a metal roof
- Extended roof life — the plywood/foam recover system protects the original metal panels rather than replacing them
- Less disruption — recover systems are installed over the existing roof, so there’s no tear-off, and the building typically stays operational throughout the project
What This Looked Like on a Recent Project
The photos below are from a recent metal roof recover project — you can see the full progression from a bare metal roof, through plywood deck installation, to the finished white foam roof:
We’ve also completed this same recover system closer to home — including a Velocity Truck Centers location in Tolleson, AZ — helping Phoenix-area building owners cut cooling costs on their metal roofs without a full tear-off.
If your metal roof is starting to show its age, or your energy bills tell you it’s underperforming, a plywood-and-foam recover system is worth a look before you assume a full replacement is your only option.
Want to know if your roof is a good candidate? Contact Stapleton Roofing for a free inspection and a straightforward assessment of your options. As a Phoenix-based, family-owned commercial roofing contractor, we’ve helped local building owners cut cooling costs and extend roof life without the expense of a full tear-off.
Frequently Asked Questions
Does spray foam roofing work on metal roofs?
Yes. Once plywood decking is installed over the existing metal panels to create a smooth, uniform surface, spray polyurethane foam (SPF) can be applied directly on top, along with a protective elastomeric coating.
How much does spray foam improve a roof’s R-value?
Closed-cell spray polyurethane foam typically provides around R-6 to R-7 of insulation per inch, depending on the product and density used. A 1″ application meaningfully increases the total insulating value of a roof that previously had little to none.
Is a recover system cheaper than a full roof replacement?
In most cases, yes. Because the plywood and foam system installs over the existing metal roof rather than removing it, you avoid the labor, disposal, and structural costs of a full tear-off.
How long does a foam roof recover system last?
With proper maintenance, foam roofing systems can last 20+ years, and unlike many roofing systems, they can typically be recoated rather than replaced at the end of their service life.
Related reading: Signs Your Commercial Roof Needs Attention | TPO vs. Foam Roofing: Which Is Right for Your Building?