I have an old (1980) Frontier wood burner (not UL listed) sitting in front of an alcove. I'd like to replace it with a Regency F3100--The ceiling in the alcove is 77". I have no problem raising the ceiling to fit Regency specs--But I have one installer telling me I can't insert the F3100 and build a surround w/a mantle and another saying I can. Of course we intend to create air space and vents using fireproof materials.--I hate to lose the Frontier and hope to bring it back to life in a 30'X30' foot barn I have--But-I want to be safe w/installation of the new Regency. Stove dealers tell me I can't insert a wood burner into an alcove at all. The chimney above the alcove is 8" steel Majestic tripple wall chimney pipe.--- the alcove and chase are not brick but the installers tell me the chase is safe.---Thanks in advance for any insights you might offer---