When I built my current home four years ago I choose to use an Isokern "Masonry Pre-Fab" fireplace. Recently, I have been exploring options on converting the fireplace with a wood burning insert. Isokern claims that their products have not been tested for this type of use and will not support it. I have spoken with several stove dealers and most don't see a problem with using a wood insert. One dealer told me he spoke with an Isokern rep and was told that Isokern's concern with an insert was specific to the possibility of the insert's expansion when hot and the resulting pressure that might be placed on the masonry structure. Has anyone had similar experience or advise on how to proceed? I would appreciate any assistance. Thanks.