Thanks for such an informative site. I've done a lot of reading here the past couple of weeks and have my Jotul C 450 being delivered tomorrow. I'll be self installing. The floor of my existing fireplace is about 3/4" lower than the hearth. Because the C450 sits partially on the hearth, I think I need to raise the floor. The easiest way I can think of would be to pour a bit of concrete in the firebox to make the floor flush. Does anyone see a problem with doing this? Any other safe and easy ways to raise the insert 3/4 inch? Thanks for taking the time to read and answer my post.