High-performance Underlayment
High-performance Underlayment | Metal Roofing | Roofing | Sewanee
In Sewanee’s rolling highlands, weather can change in a heartbeat. HEP’s high-performance underlayment is the invisible hero beneath your metal roofing, locking out wind-driven rain, snow, and the relentless Southern sun. Unlike traditional felt, our advanced synthetic barrier resists tearing on sharp panels, lies flat on steep pitches, and breathes just enough to let trapped moisture escape—so your attic stays drier, cooler, and healthier all year long.
When you choose HEP, you’re choosing local experts who prep every deck with precision, fasten each layer with corrosion-proof anchors, and back the work with warranties that rival the mountain views. The result is a roof system that looks stunning in standing seam or screw-down panels and performs even better, slashing maintenance costs and delivering decades of peace of mind. Protect your investment from the deck up—starting with HEP’s premium underlayment.
FAQs
Why is high-performance underlayment so important for metal roofs in Sewanee’s climate?
Sewanee sits on the Cumberland Plateau at roughly 2,000 ft elevation, which means frequent temperature swings, heavy summer downpours, and occasional snow or ice. A premium underlayment acts as the roof’s secondary water-shed, blocking wind-driven rain and melt-water that can work under metal panels during storms or freeze–thaw cycles. It also provides a high-temperature barrier (up to 250 °F) so the asphalt in the underlayment will not liquefy under a sun-heated metal roof. Without this layer, even the best standing-seam panels can allow moisture to penetrate the sheathing, leading to mold, rot, and interior leaks.
What type of underlayment do you install under metal roofing in Sewanee?
We install a self-adhering, UV-resistant synthetic underlayment reinforced with woven scrim. It is ASTM D1970 compliant (ice-and-water shield standard) and specifically rated for high-temperature metal assemblies. The peel-and-stick backing seals around nails and clips, eliminating the cap-nail penetrations required by traditional felt. For areas prone to ice dams—north-facing eaves, valleys, and dormers—we double-layer the membrane for extra protection.
How does a high-performance underlayment improve energy efficiency and comfort?
The reflective top surface of our synthetic membrane reduces heat transfer into the attic by up to 30 °F compared with saturated felt. Less heat gain means your HVAC system works less, reducing summer cooling costs. The scrim reinforcement also adds a modest sound-dampening layer, softening rain impact noise that is common with metal roofs. Homeowners report noticeably quieter interiors during thunderstorms.
Is this underlayment suitable for both new construction and reroof projects?
Yes. For new construction, we adhere the membrane directly to clean, dry OSB or plywood sheathing, creating a monolithic barrier before metal panels are installed. For reroofs we remove the old roofing to the deck, make any required deck repairs, and then apply the same membrane. Because it is only 45 mils thick and self-sealing around fasteners, it adds negligible weight and meets current International Residential Code (IRC) requirements for recover projects.
How long does underlayment installation take and will it disrupt my daily routine?
A typical 3,000 sq ft roof deck takes one day to prepare and cover with the self-adhering membrane. Because the product does not require mechanical fastening every 6 inches like felt, the crew moves quickly and quietly. Most clients experience minimal disturbance—no loud nail guns, fewer workers on the roof, and the house remains fully watertight at the end of each workday, even if metal panels are installed later.
What warranties and maintenance come with your high-performance underlayment system?
The manufacturer supplies a 30-year limited material warranty, and we add a 10-year workmanship warranty that covers labor in the unlikely event of underlayment failure. Once the metal roof is on, the membrane is concealed and maintenance-free; simply keep gutters clear and schedule an annual roof inspection so we can check flashings and panel fasteners. If panels ever need to be removed for service, this underlayment self-seals again when re-fastened, so its water-tight integrity remains intact.