TREX CO INC

Amended and Restated By-Laws of the Company dated February 21, 2024

. On February 21, 2024 the Board of Directors of the Company approved and adopted amendments to Article III, Section 2 and Article IV, Section 1 of the Company’s Amended and Restated By-laws, effective immediately, to (a) clarify that that notwithstanding the statement that Directors need not be stockholders of the Corporation, if the Corporation has in effect at any time any Stock Ownership Guidelines applicable to Directors, Directors shall comply with such Guidelines and (b) to provide that if the Chairman is unavailable to preside over a meeting of the Board of Directors, then, if there is a Vice Chairman and/or a Lead Independent Director serving at the time of such meeting, the Vice Chairman or the Lead independent Director, in that order, shall serve as Chairman of the Board of Directors for such meeting.

Insider Trading Arrangements

. During the quarter ended December 31, 2023, none of our directors or officers (as defined in Rule 16a-1(f) of the Exchange Act) adopted, modified or terminated any contract, instruction or written plan for the purchase or sale of our securities that was intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) of the Exchange Act or any non-Rule 10b5-1 trading arrangement (as identified in Item 408(c) of Regulation S-K).