Frequently Asked Questions

Our 29-Gauge AG Panels are a cost-effective, durable solution primarily used in residential and agricultural projects. They feature a deep-channel anti-siphon rib to prevent leaks and five 3/4″ major ribs.

Our 26-Gauge PBR Panels are the heavy-duty standard for commercial, industrial, and residential builds. Made of thicker steel, they feature 1-1/4″ trapezoidal ribs and a purlin-bearing leg that provides an extra weather-tight barrier against high winds and moisture. Both offer a 36-inch coverage width.

Yes! To help you save money and eliminate waste, both our AG and PBR metal panels can be custom cut to the whole inch, in lengths ranging from 3 feet up to 40 feet.

Yes, our painted panels are finished with the industry-leading Sherwin-Williams SMP WeatherXL™ system. We offer a 40-year paint warranty on our 29-gauge AG panels and painted 26-gauge PBR panels. Please note: panels are factory-finished and warrantied on the exterior (top) side only. *The silver galvalume has a 20 year clear coat warranty. 

No, a metal roof will actually keep your home cooler than traditional asphalt shingles. Because metal panels have a very low thermal mass, they instantly reflect solar radiation away from your home rather than absorbing and holding onto heat like heavy asphalt shingles. While shingles are bound by petroleum-based tar that absorbs and traps intense desert heat long after sunset, metal panels reflect solar radiation and cool down almost instantly the moment the sun goes over the horizon.

Cool Color Advantages: Choosing a lighter “cool color” can optimize your energy savings even further. At Thunder Mountain Metal Sales, our lighter shades (Polar White, Light Stone, and Ash Grey) reflect heat so effectively that they stay about 12% cooler than our darker color profiles (Ivy Green, Charcoal Grey, Burnished Slate, and Coco Brown).

This is a common myth based on the sound rain makes on old open-frame barns. Residential metal roofs are installed over a solid roof deck and underlayment, which dampens the noise. A residential metal roof is no more or less noisy than a traditional asphalt shingle roof.

Metal panels are incredibly tough and highly resistant to hail damage, preventing structural leaks entirely. Unlike traditional roofing materials that can crack or puncture, a metal roof will not be penetrated by hail.

• Class 4 Impact Resistance: Many high-quality metal roofing products earn a Class 4 impact rating from Underwriters’ Laboratory (UL)—the highest rating possible. This means the material can withstand severe impacts without cracking.

• Insurance Savings: Because of this exceptional durability, many homeowners insurance companies offer discounted premium rates for homes protected by metal roofs.

• Cosmetic vs. Functional: While exceptionally large hailstones might occasionally cause minor cosmetic indentations, the structural integrity and premium painted coatings of the panels remain fully uncompromised.

The Short Answer

Yes, you can building-code-wise, but we don’t recommend it. While building codes in Pima and Cochise County legally permit you to install a metal roof over an existing layer of asphalt shingles, doing so leaves you with a maximum allowed double-layer roof.

Why Thunder Mountain Metal Sales Recommends a Clean Tear-Down

When you invest in a lifetime product like a metal roof, you want to ensure it is built on a flawless foundation. Here is why we always recommend tearing your roof down to a fresh, bare deck:

Avoiding “Oil Canning” and Dimpling: Asphalt shingles are rarely perfectly flat. If you overlay metal panels directly on top of them, the uneven texture of the shingles underneath will telegraph through the metal. This causes a cosmetic distortion known as “oil canning” or dimpling, which compromises the sleek, professional look of your new roof.

Securing a Solid Base: Installing over old shingles hides potential wood rot, water damage, or structural issues in the underlying deck. Going down to the bare wood allows you to inspect, repair, and guarantee a perfectly solid foundation for your lifetime investment.

We proudly utilize 100% American-made steel, specifically from Steel Dynamics (SDI), for our roofing and siding panels. Choosing USA-made AZ50 Galvalume® steel ensures our products adhere to the most rigorous quality control standards in the world for exceptional strength and consistency, while also supporting local jobs and reducing shipping lead times.

Yes, we precision-fabricate custom metal trim right here in our Tucson shop to perfectly seal and finish your building. Our trim is manufactured from durable 26-gauge steel, sold in standard 10’4″ sections, and is available in colors that seamlessly match your metal panels.

Our Value-Engineered Inventory includes factory seconds, custom miscuts, and overstock materials. It provides the same USA-made structural strength at a heavily reduced price point. Because these are deeply discounted, they are sold strictly “As-Is” and may contain cosmetic blemishes; they are final sale and do not come with a warranty. They are perfect for sheds, privacy fencing, or raised garden beds

Absolutely. We stock a comprehensive selection of installation accessories, including:

• Screws: Standard metal-to-wood, metal-to-metal, metal-to-OSB, and Long Life ZXL screws with a Zinc-Aluminum alloy head to prevent rust.
• Roof Boots: Standard, High-Temp (withstands up to 450°F), and split-design Retrofit boots to seal pipes and vents.
• Closures & Sealants: Profile-cut foam inside/outside closures, vented polyester rolls, and butyl tape.
• Underlayment: HydraShell Supreme, an advanced 100% synthetic underlayment that is 20 times stronger than traditional #30 felt and boasts a Class A Fire Rating.

The Short Answer

Yes, absolutely. Thunder Mountain Metal Sales carries a comprehensive inventory of heavy-duty structural steel components to support your residential, agricultural, and commercial building projects.

Our Structural Steel Inventory

Whether you are framing a metal building, constructing a custom carport, or reinforcing a structural design, we supply the reliable, high-quality steel you need. Our standard inventory includes:

Cee Purlins: Essential for structural framing, providing strong support for roof and wall panels.

Channel & Receiver: Perfect for structural tracks, framing, and heavy-duty reinforcement.

Square Stock: Versatile square tubing ideal for columns, posts, and fabrication.

Angle Iron & Base Angle: Crucial components for structural bracing, foundational corners, and secure anchoring.

The Bottom Line
At TMMS, we are more than just a metal panel provider—we are your one-stop shop for the complete structural backbone of your build. Contact us today to check our current lengths, gauges, and availability for your next project.

The Short Answer

Our office is open Monday through Friday from 8:00 AM to 4:30 PM, but please note that our yard closes for pickups at 4:00 PM.

Operating Hours at Thunder Mountain Metal Sales

To ensure your order is loaded safely and efficiently, we keep our office and yard hours slightly different:

Office Hours: Monday – Friday | 8:00 AM – 4:30 PM

Material Pickup Hours: Monday – Friday | 8:00 AM – 4:00 PM

⚠️ Important Pickup Note: Because loading large metal panels and structural steel safely takes time, our yard crew stops loading at 4:00 PM sharp. Please make sure to arrive at least 30 minutes before the yard closes so we can get you loaded, secured, and back on the road safely!

The Short Answer

No, we do not offer complete building kits that include the structural steel framing. While we don’t supply the structural framework or engineering blueprints, we can provide the complete, high-quality “skin” packages to cover and protect your building.

What is Included in Our “Skin” Packages?

If you already have your wood or steel framing sourced, Thunder Mountain Metal Sales is your premier partner for custom-cutting the exterior materials. We can fully equip your project with:

Metal Panels: Custom-cut roof and wall panels available in your choice of profile, gauge, and color.

Matching Trim & Flashing: Everything from ridge caps and eave trim to corners and J-channels for a clean, watertight finish.

Fasteners & Accessories: Color-matched screws, closure strips, and the exact hardware required to secure your panels to your frame.

The Bottom Line
Think of us as your exterior specialists. Bring us your panel counts and trim measurements, and we will manufacture the pristine, durable metal skin your building deserves.

We accept returns on unopened accessories, but all custom-manufactured panels and trim are final sale.

• Eligible for Return/Exchange: Unopened, undamaged accessories such as bulk screws, fasteners, and pipe boots can be returned or exchanged.

• Not Eligible for Return/Exchange: We cannot accept returns or exchanges on any metal roofing panels or custom trim, as these are custom-fabricated to your specific invoice dimensions.

💡 Pro-Tip for a Seamless Order: To ensure your project goes smoothly, we highly encourage you to review our website’s product diagrams, double-check your invoice measurements before processing payment, and inspect your materials completely at the time of pickup or delivery. If we made a manufacturing error relative to your invoice, we will happily correct it immediately!

No, metal panels cannot be installed on a completely flat roof. Metal roofing requires a minimum slope (pitch) to ensure proper water runoff and prevent pooling.

The minimum slope requirements depend on your material gauge and whether you use a lap sealant:

• Standard 29-Gauge AG Panels (Without Sealant): Requires a minimum slope of 3:12 (a 3-inch vertical drop for every 12 inches of horizontal run). With a proper lap sealant, this can go lower.

• Heavy-Duty 26-Gauge PBR Panels: Can safely go as low as a 1:12 slope without sealant due to their deeper rib profile.

Yes, we specialize in “exposed fastener” metal roofing systems. This means the color-matched screws are installed directly through the face of the panel and remain visible. Exposed fastener systems are the industry standard for residential, agricultural, and commercial projects across Arizona because they offer incredible wind resistance, strength, and cost-effectiveness.

Exposed fastener metal roofing panels are the top choice for residential and agricultural projects throughout Southern Arizona. They offer a highly cost-effective alternative to hidden or standing seam panels and are significantly easier for both professional roofing contractors and DIY homeowners to install safely and efficiently.

Yes, 29-gauge metal is the absolute industry standard for residential metal roofing. It provides the perfect balance of structural durability, lightweight handling, and cost efficiency. Beyond residential roofing, our high-quality 29-gauge panels are widely used throughout Southern Arizona for metal home siding, property fencing, porch skirting, and carports.

For maximum structural integrity and weather resistance, Thunder Mountain Metal Sales recommends the following fastening schedules:

• 29-Gauge AG Panels (Classic/Imperial Rib): Space screws every 2 feet along the length of the panel.

• 26-Gauge PBR Panels (R-Panel): Because of their heavier thickness and deeper structural ribs, screw spacing can be extended up to a maximum of 4 feet apart.

We provide free material estimates based on measurements or diagrams provided directly by the customer. To keep our prices competitive and lead times short, we do not perform on-site field measurements.

• Need Help Measuring? Don’t worry! We provide a comprehensive, easy-to-follow roof measurement handout at our office, or check out this video we made. This guide will walk you through exactly what dimensions and angles to note so we can generate a highly precise, itemized quote for your project.

Yes, you can absolutely walk on a metal roof, but it must be done properly to avoid denting the panels. Whether you are installing solar panels, cleaning out your gutters, or accessing your chimney, metal roofing is sturdy enough to support your weight when walked on correctly.

• How to Walk on Metal Panels safely: You should always wear soft-soled shoes with good traction (like clean sneakers) and walk directly over the roof structural supports (the purlins or wood decking underneath). Avoid stepping directly on the high ribs of the panels, as concentrated weight on an unsupported area can cause minor cosmetic denting.

• Safety First: Metal roofs can be slick when wet or dusty. We always recommend consulting with a professional or referencing our specific panel guidelines before stepping onto your roof.

No, a metal roof will not make your home any colder during the winter months. It is a common misconception that metal panels act like an ice box when the desert temperatures drop.

• The Role of Attic Insulation: In a standard residential home, the roof panels sit above a vented attic space. The temperature of your roof structure has no direct effect on your living space because your home’s thermal boundary is controlled by your attic insulation.

• Year-Round Comfort: It is the high-quality insulation resting on your attic floor that keeps your heated air inside your living areas. A metal roof works harmoniously with proper insulation and ventilation to maintain a highly stable, comfortable indoor temperature all year long.