I just called my installer, who just put the stove in a few months ago. He can't confirm if there is a top cap plate or if he insulated at the top, and wants to charge a service fee to check this out. I'm not climbing up 3 stories to check on my own. I guess I'll wait till I get it swept this spring. Meanwhile, they don't install block off plates. Instead they want to install an "insulate". I'm not sure if he just means stuff it with insulation, or if there is a separate device that the industry refers to as an "insulate"? And who should I look to for a block off plate? Do installers typically do this?