Roofing Materials
Polyglass Polystick XFR Underlayment
The underlayment is the one part of your roof you'll never see after installation, yet it is one of the most important layers protecting your home. It serves as the last line of defense against fire, water, and wind, which is why we refuse to treat it as an afterthought.
We install Polyglass Polystick XFR as the full-deck underlayment beneath every standing seam metal roof we build. We chose it on purpose because it works with the rest of our roofing system, including the standing seam panels, high-wind clip system, flashings, and ember-resistant vents. Nothing on our roof is an accident.
Unlike basic nail-down felt or mechanically fastened synthetic underlayments, Polyglass Polystick XFR is a self-adhered, fire-resistant, high-temperature membrane engineered specifically for demanding metal roofing applications. It helps protect your home from fire, water intrusion, high winds, and the extreme temperatures generated beneath a standing seam metal roof.
Learn more about our roofing materials: Roofing Materials
Standing seam roof system cross section: a plywood roof deck, Polyglass Polystick XFR self-adhered membrane, concealed clips, standing seam metal panels, and flashings working together as one roofing system.
Installing Polyglass Polystick XFR self-adhered underlayment on a plywood roof deck before the standing seam roof is installed.
What Is Polyglass Polystick XFR?
Polyglass Polystick XFR is the full-deck underlayment we install beneath every standing seam metal roof. It is a self-adhered, fire-resistant, high-temperature synthetic underlayment engineered specifically for metal roofing. Unlike nail-down felt or basic mechanically fastened synthetics, it bonds directly to the roof deck to create a continuous protective membrane.
Polyglass Polystick XFR is built using Polyglass ADESO dual-compound technology, combining a polymer-modified bitumen top compound with an aggressive self-adhesive SBS compound underneath. This dual-compound construction creates a strong, permanent bond to the roof deck while providing exceptional durability beneath standing seam metal roofing.
At 80 mils thick, the membrane is fiberglass reinforced for outstanding strength and dimensional stability. Its cavitated anti-skid top film provides secure footing during installation and is rated for up to 180 days of UV exposure, offering protection if construction schedules are delayed.
Standing seam metal roofs become significantly hotter than many other roofing materials. Polyglass Polystick XFR is rated to 265°F, making it suitable beneath steel, aluminum, and copper roofing systems. Many traditional felt products and basic synthetic underlayments are not designed for those temperatures.
The membrane also incorporates Polyglass Burn-Shield Technology for fire and ember resistance, adding another layer of protection beneath the finished metal roof.
Learn more about our complete approach to metal roof underlayments:
Metal Roof UnderlaymentWhat Most Roofers Put Down (And Why It Falls Short)
Most residential metal roofing projects use either 30-pound felt or a basic mechanically fastened synthetic underlayment. These products are widely available, inexpensive, and quick to install, making them the default choice on many lower-cost roofing projects.
Mechanically fastened underlayments depend on thousands of nails or staples to secure them to the roof deck. Every fastener creates a penetration through the membrane. Once the finished roof is installed, those penetrations are covered, but the underlayment itself does not create the same continuous seal as a fully adhered membrane.
Traditional felt and many basic synthetic underlayments are also not engineered for the temperatures generated beneath standing seam metal roofing. Steel, aluminum, and copper panels can become extremely hot under Southern California sun, making high-temperature performance an important part of a long-lasting roofing system.
Wind performance is another important difference. Mechanically fastened underlayments rely on fasteners to stay attached to the roof deck, while a self-adhered membrane bonds across the entire surface. That continuous bond provides a more secure secondary weather barrier beneath the finished roof.
That added material and labor is exactly why it is missing from many low bids.
Fire Protection: A Class A Assembly, Not Just a Panel
A non-combustible standing seam metal panel is only one part of a fire-resistant roofing system. Real wildfire protection comes from the entire roof assembly working together. That is why we pair our standing seam panels with Polyglass Polystick XFR, ember-resistant roof vents, and a fully sealed roof deck to create a complete Class A assembly, not simply a fire-rated panel.
Metal panels do not burn, but wind-driven embers can reach the roof deck through vents, roof penetrations, and other vulnerable openings. If embers reach the deck, the underlayment becomes the next layer of protection.
Polyglass Polystick XFR incorporates Polyglass Burn-Shield Technology, providing fire and ember resistance that helps achieve a UL Class A fire rating over a combustible plywood deck in a single-layer assembly. Working together with the metal roofing panels, the sealed roof deck, and ember-resistant roof vents, it creates a roofing system engineered to resist fire where it matters most.
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Water Intrusion: A Sealed Deck That Self-Seals Around Every Fastener
The roof deck is your home's last line of defense against water intrusion. That is why we install Polyglass Polystick XFR as a fully adhered membrane across the entire roof deck instead of relying on mechanically fastened underlayment.
Because the membrane bonds directly to the plywood, it forms one continuous secondary water barrier beneath the standing seam roof. It also self-seals around every fastener, helping prevent water from following fastener penetrations into the roof deck. Mechanically fastened underlayments leave thousands of fastener penetrations that do not provide the same continuous seal.
If a metal panel is ever damaged by storm debris or temporarily removed years later for maintenance or another improvement, the bonded membrane continues protecting the roof deck beneath it. It serves as the backup layer that helps keep water out of your home even when the primary roofing surface has been compromised.
Our water management system extends beyond the field of the roof. We also install ice and water shield at critical areas such as eaves and valleys, where water is most likely to collect or back up.
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Ice and Water ShieldWind: A Membrane That Bonds to the Deck
High winds test every layer of a roofing system, not just the metal panels. That is why we install Polyglass Polystick XFR as a fully adhered membrane that bonds directly to the roof deck instead of relying on mechanically fastened felt or basic synthetic underlayment.
Because the membrane is adhered across the entire deck, it cannot lift or tear away in high winds the way mechanically fastened underlayments can. The result is a stronger secondary weather barrier that continues protecting the roof deck during severe wind events and wind-driven rain.
The membrane also works with our high-wind standing seam clip system. We install heavy-duty concealed clips using two fasteners per clip, spaced 12 inches on center in the field and 9 inches on center at the roof perimeter. Together, these components help the roof resist uplift while reducing the risk of wind-driven rain reaching the roof deck.
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Why We Spec It on Every Roof
Fire, water, and wind are not separate problems. They are challenges the entire roofing system must solve together. That is why we specify Polyglass Polystick XFR on every standing seam roof we build.
The system begins with a non-combustible standing seam metal roof panel. Beneath it is an 80 mil Polyglass Polystick XFR self-adhered membrane with Polyglass Burn-Shield Technology, fiberglass reinforcement, and a 265°F temperature rating. The roof is completed with our high-wind clip system, hand-formed flashings, and ember-resistant roof vents, creating a roofing assembly engineered to perform as one system.
There is an honest trade-off. Polyglass Polystick XFR costs more than felt or a basic synthetic underlayment, and it requires more labor because the membrane is fully adhered across the entire roof deck. That is exactly why many lower bids leave it out. We don't.
The proof is in the specifications.
Nothing on our roof is selected by accident. Every component is chosen because it strengthens the components around it, creating a standing seam roofing system engineered to deliver long-term protection against fire, water intrusion, and high winds.
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Frequently Asked Questions
Reviews
What Our Clients Say
Susan M.
Calabasas, CA
The Metal Roof Pros installed a dark bronze standing seam on our home and it completely transformed the exterior. Their crew was detail-oriented and left the property spotless every day. The finished roof is a showpiece. We get compliments from neighbors constantly.
Michael T.
Thousand Oaks, CA
After getting five quotes from different companies, The Metal Roof Pros were the only team who could explain their gauge, clip spacing, and underlayment system in detail. Their knowledge of standing seam installation is unmatched. The roof looks and performs flawlessly.
Jennifer L.
Encino, CA
We hired The Metal Roof Pros for a charcoal gray Kynar 500 standing seam roof. Karen walked us through every color option and helped us choose the perfect shade to match our stone facade. The color is exactly what we wanted and the finish is stunning.
David R.
Malibu, CA
Living on the coast, we needed a roof that could handle salt air. The Metal Roof Pros recommended their aluminum standing seam system and explained exactly why steel would not work at our location. Two years later, zero corrosion issues. Worth every penny.
Patricia W.
Pacific Palisades, CA
After the 2024 wildfires, we prioritized fire protection for our rebuild. The Metal Roof Pros installed a Class A rated standing seam system with proper ember-resistant detailing at every penetration point. Our insurance company was very impressed with the fire rating documentation.
Robert K.
Agoura Hills, CA
We own a commercial property in Agoura Hills and needed a reliable roofing contractor. The Metal Roof Pros handled our 12,000 square foot standing seam installation on schedule and on budget. Their commercial crew was professional and incredibly efficient.
Maria G.
Sherman Oaks, CA
Karen and the entire Metal Roof Pros team made the process simple from estimate to final walkthrough. They installed seamless rain gutters to match our new metal roof and the integration between the two systems is perfect. Everything drains exactly where it should.
James H.
Beverly Hills, CA
We had The Metal Roof Pros install a 22-gauge standing seam on our hillside property. The heavier gauge was recommended for the wind exposure and steep pitch. The installation quality is exceptional. Every panel, clip, and flashing is precise.
Linda C.
Woodland Hills, CA
The attic ventilation work The Metal Roof Pros did alongside our standing seam installation made a huge difference in our cooling costs. They installed ridge vents and balanced the intake system properly. Our upstairs rooms are noticeably cooler in summer.
Carlos A.
Pasadena, CA
The Metal Roof Pros replaced our old tile roof with a matte black standing seam and it completely modernized our 1960s ranch home. The crew handled the tear-off and new installation in under a week. Clean work, great communication, outstanding result.
Sarah P.
Studio City, CA
We added new rain gutters when The Metal Roof Pros installed our standing seam roof. They color-matched the gutters to the roof panels perfectly. The seamless gutter system handles our heaviest rains without any overflow issues. Excellent craftsmanship throughout.
Thomas B.
Westlake Village, CA
As a retired general contractor, I am extremely particular about installation quality. The Metal Roof Pros exceeded my expectations. Their clip spacing, flashing details, and underlayment application were textbook perfect. This is how metal roofing should be done.
Angela D.
Brentwood, CA
We chose a slate blue Kynar 500 finish and it looks absolutely beautiful on our contemporary home. The Metal Roof Pros helped us visualize the color with actual panel samples before we committed. The 35-year paint warranty gave us total confidence in the investment.
Mark S.
Northridge, CA
Our commercial building needed a complete re-roof and The Metal Roof Pros delivered a standing seam system that solved our persistent leak problems. Their attention to flashing details around our HVAC units and skylights was impressive. No leaks since installation.
Diane F.
Topanga, CA
Living in a Very High Fire Hazard Severity Zone, our insurance required a noncombustible roof. The Metal Roof Pros installed a Class A rated standing seam system that satisfied every code requirement. Our premium dropped significantly after we submitted the documentation.
Susan M.
Calabasas, CA
The Metal Roof Pros also handled our attic insulation upgrade when they installed the metal roof. The combination of reflective metal panels and proper insulation cut our summer energy bill by about 20%. The house stays cooler without running the AC as hard.
Robert K.
Agoura Hills, CA
We brought The Metal Roof Pros back for a second commercial project because the first installation was flawless. They understand the unique demands of commercial roofing, including foot traffic paths, equipment mounting, and drainage slopes. Highly recommended for any commercial job.
Maria G.
Sherman Oaks, CA
Our home is near the coast and The Metal Roof Pros recommended aluminum panels instead of steel for our location. The aluminum standing seam system has held up perfectly against the salt air. No corrosion, no discoloration, and the warranty covers us for decades.
James H.
Beverly Hills, CA
The gutter installation by The Metal Roof Pros was just as impressive as the roof work. They used 6-inch seamless aluminum gutters with hidden hangers, and the downspout routing was carefully planned to keep our landscaping protected. Outstanding detail work.
Jennifer L.
Encino, CA
When it came to fire hardening our property, The Metal Roof Pros provided a complete assessment. They installed a noncombustible standing seam roof and sealed every vent and soffit with ember-resistant materials. Our home now meets the latest California wildfire building codes.
Get Your Free Quote
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- Existing home: we measure your roof from high-resolution satellite imagery and email you a detailed written quote.
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