Hi. I have a vented gas fireplace that does not have a liner (old house). I'd like to line it but have one problem: halfway up the chimney is a horizontal metal bar that crossed right in the middle of the flue - likely a support beam. The chimney sweep said that this would prevent a metal tube chimney liner from being inserted (makes sense) and we needed to look at a unvented solution. I really like the look of the vented we have now so hoping there are creative solutions out there. Any thoughts would be appreciated.