Best Underdeck Company in York County, SC Express Sunrooms is one of the leading Underdeck Companies in York County, SC, specializing in high-quality underdeck systems that create dry, functional spaces beneath your deck. Our expert team ensures precise installation and long-lasting durability, helping you maximize your outdoor living area. Call us at 803-866-1595. Visit: https://www.expresssunrooms.com/under_deck_ceiling_underdecking