A fireplace surround structure is disclosed. The fireplace surround structure includes a mantel portion, a first vertical leg portion and a second vertical leg portion. The first leg portion and the second leg portion extend downward from the mantel portion at opposite ends to form a unitary fireplace surround structure. Each leg portion has a skeletal bar frame with a plurality of bar portions defining a three sided generally rectangular structure. Each of the sides has a lightweight non-combustible board portion attached on the exterior of the frame. The fireplace surround structure is open to one side and mountable on a wall surface. Each board portion is cast from a mix of Portland cement, silica, and cellulose fibers, which are combined and sintered into a flat board structure.