What Is Roof Underlayment and Why Does It Matter in Charlotte NC?

Synthetic underlayment outperforms felt #15 in 5 ways critical to Charlotte humidity: (1) lifespan 30-50+ years vs felt 5-10 years; (2) tear strength 3-5x higher than felt (resists install damage and wind uplift); (3) waterproof vs water-resistant (felt absorbs moisture and breaks down); (4) UV resistant for 60-90 days exposure during install (felt becomes brittle in sun within 2-3 weeks); (5) lighter weight reduces installer fatigue and improves install quality. Manufacturer top-tier warranties (GAF Golden Pledge, CertainTeed 5-Star Plus, OC Platinum) REQUIRE synthetic underlayment — felt installs disqualify from premium warranty coverage.

NC IRC §R905.1.2 requires ice-and-water shield in 4 critical locations: (1) eaves — 3-6 feet from the gutter edge (varies by climate zone, Charlotte standard is 3 ft minimum, 6 ft recommended for north Mecklenburg / Lake Norman ice-event areas); (2) valleys — full length where two roof slopes meet; (3) penetrations — around chimneys, skylights, plumbing vents, and HVAC curbs; (4) low-slope sections — any pitch under 4/12. Best Roofing Now's standard install includes ice-and-water shield in all 4 locations as part of every reroof at no upcharge.

Don't — the savings is too small and the cost is too high. Felt #15 saves $300-$700 vs synthetic on a typical 30-square Charlotte reroof. But it loses: (1) 50-year top-tier manufacturer warranty (worth $5,000-$15,000 in coverage value); (2) 5-10 year roof lifespan in Charlotte humid climate (forces earlier reroof costing $11,000-$22,000); (3) install quality (felt tears under foot traffic, leaving uncovered areas). The 'savings' is the most expensive long-term choice. Always insist on synthetic underlayment.

Underlayment is typically thin (15-30 mil thick) but the spec matters more than thickness. Standard synthetic underlayment specs: Tyvek/Titanium PSU30 (30 mil, 30-yr warranty), GAF Tiger Paw (similar 30 mil, comes in GAF system bundle), Owens Corning ProArmor (30 mil, comes in OC system bundle), Atlas Summit (30 mil budget option). Premium synthetic with breathable membrane: $0.50-$0.70/sq ft, allows attic moisture to escape upward. Ice-and-water shield is thicker (40-60 mil rubberized) and self-seals around fasteners — the only roof material that adheres permanently to decking.

Yes — synthetic underlayment + ice-and-water shield at all required locations is included in every Best Roofing Now reroof at no upcharge. Standard spec: GAF Tiger Paw (with GAF Master Elite Golden Pledge installs), CertainTeed RoofRunner (with CertainTeed SELECT 5-Star Plus installs), Owens Corning ProArmor (with OC Platinum installs), or Tyvek/Titanium PSU30 (universal premium synthetic). Plus Grace Ice & Water or GAF WeatherWatch ice-and-water shield 3-6 ft from eaves, full valley length, and around all penetrations. Specifications match the manufacturer top-tier warranty requirements at every brand.