I have been seeing alot of you talking about installing block-off plates above your inserts and hearth-mount stoves. My insert (Flame 1.9-I made by SBI,similar to Osburn and Drolet models) is NOT on an outside wall. It is directly in the middle of the house. I have a Levit Ranch (in Levittown, duh), and every house in this town was built between 1947-50 on a concrete slab with a chimney smack-damn in the center. The house is two stories, with the stove on the ground floor. I have no problems with draft either in the stove, or cold air seeping down around the SS liner. I do have access to the back of my insert which most people do not (the original fireplace was open on both sides - kitchen and living room), so it would not be that difficult to install if I had to. If I did, could I just insulate a few feet above the plate with mineral wool or something similar( and affordable)? What would be the benefits of installing one, since I'm not experiencing any problems right now? I defer to you - my trusted gurus.