Exhibit 99.1 NEWS RELEASE TREX COMPANY REPORTS FIRST QUARTER 2024 RESULTS Robust First Quarter Sales Reflect Double-Digit Sell-Through for Premium Products and Early Buy Program Gross Margin Expansion Driven by Higher Utilization and Cost Efficiencies Guiding to Second Quarter Revenues of $380 million to$390 million Reaffirms Full Year 2024 Guidance WINCHESTER, Va. —May 9, 2024— Trex Company, Inc. (NYSE:TREX) (Trex or Company), the world’s #1 brand of high-performance, low-maintenance and eco-friendly comp ...