Question: I just came across your site and have a question. I just bought an old Victorian house. The fireplace was reconstructed in 1975 or so after an earthquake. At that time the chimney was redone and so was the type of fireplace. This one has a long horizontal opening above the firebox approximately 24 inches by 6 inches. It also has a square "vent" next to the face of the fireplace on either side. What type of fireplace is this? The face of the fireplace is done in flagstone laid down horizontally - brick like. At some point I would like to redo this face to be more Victorian but I would first like to know what I'm dealing with. As it is, it's pretty ugly. Any help you could give me in identifying what I've got would help. Alice Henault email@example.com Answer: Chances are that a "heatform" was installed, which is a heavy steel box that forms the inside area of the fireplace. Some of these have a second wall built around them, which creates a convection air chamber....other times, this chamber is formed by the space between the metal box and the masonry that surrounds it. In either case, it is dangerous to close off those openings as they provide the cooling air for the fireplace.