This is much less expensive than an actual coffered ceiling as this is simply a single cast which when put tip to tip creates this larger secondary shape. One cast covers a little over 12sq feet of ceiling. Here is a link to this item - our #2964. To figure out how many pieces will cover your ceiling calculate the square footage of the room (Width x length) and divide by 12. This will give you an approximate piece count. 2964. See Blue link to understand how they connect