I have a gas heater in the garage which was in place for years before the lean-to was built. I did extend and turn the vent using two 45 degree elbows up and went through the new lean-to roof after the picture was taken four years ago. The termination is now 10 feet away from the windows above the roof.
THANK YOU ! Sure glad you relocated it. The windows caught my eye...fumes, open window, funeral...not a good combination. Had snow like that on my steel roof, then Mr. Sun FINALLY came out,'freight train came' ...snow slid onto deck for about 7 minutes....