Any exterior change to your home, once your home was completed by the builder, requires HOA approval. This includes changes to or additions of fences, retaining walls, decks, patios, sidewalks, structures, exterior color changes, removal of trees that are 3″ or greater in diameter, changes to the slope of your lot, and more, detailed in Article IX of the Indentures on pages 12-14.
Approval is only to ensure harmony with the surrounding lots and overall aesthetics of the neighborhood. The lot owners are responsible for ensuring that their project has been properly designed for safety, necessary county permits are drawn, and implemented to ensure structural integrity.