I'd always planned to upgrade our prefab fireplace in Michigan (a Majestic WMC42) and with the discounts and (formerly) high propane prices now seemed like a good time. Here's the original setup: The lintel height is about 27", which was perfect for the Fireview. The hearth is a 42" x 20" x 2.25" concrete slab, which is thick enough for the Fireview but not really deep enough for a 20" deep stove with rear controls. I thought of various ways to extend it, and ultimately decided to slide the slab forward 8" onto posts. This would let me keep the existing stonework intact and visible and minimize the new stonework. Luckily it turned out that the slab was mostly just sitting there, it was glued to what looked to be at least two layers of micore or similar underneath but that pulled off without my even noticing it at first. The new space behind the slabs I figured I'd fill with rocks from the beach, and wrap the posts with same. Here the slab is pulled out onto 4 4x4 posts, which I glued and screwed into the floor with two-headed screws. I wrapped them with metal lath and did a scratch coat, and put down a layer on top to level and attach the slab. I framed the 8" gap with oak to match the existing trim and lined the gap with lath: Here the rear rocks are mortared in. The mortar is still wet and dark here, it wound up drying lighter than I expected: The WMC42 is the rare prefab that has a proper class-A HT2100-rated chimney, CFM's 8" ID triple-wall "type S" or "S8" chimney, also used on the Sequoia EPA fireplaces. I decided to start with the cheap route and do a direct connect; if I had draft problems I could always run a liner later. Here's the blockoff plate, I went a little nuts with the screws because the top of the fireplace was a little warped: And finally, some different views of the finished product with the stone on the posts: Notice that I pulled the stove out past the mantle, hopefully this avoids the need for a shield. (The wife doesn't want a shield.) I also put a pipe shield on the horizontal run of pipe and angled the shield up towards the stove so that the hot air comes out past the mantle. I don't currently have any additional hearth protection in front of the stove; Woodstock told me that the 10" height of the hearth counts for the 8" I need in front. I couldn't find that anywhere else but if anyone knows let me know. *EDIT* Here's the fireplace painted metallic gray to match the stove and pipe. I've done 4 fires in the Fireview so far. I've had zero draft problems, even with the first break-in fire when it was 75 degrees out. Everything they say about this stove is true. A single load of tiny splits goes forever and the stone stays hot longer than that. I've only had the top up to about 450, so it still has an extra gear or two to show me in the winter. With all the shielding the stone surround and the metal fireplace don't get very hot, and I can even run the fireplace blower if I want, which will dump any heat from the fireplace and just happens to blow right across the top of the stove to boot.