Put a gas forced air furnace in it is not new can i run the flue through the wall and then up?
Or does it need to go through the roof. THere’s no vent in the room where I put furnace, I have a new roof and just don’t want to put a hole in it if i don’t need to.
If it is a high efficiency furnace and uses PVC pipe for venting you can terminate the pipe on the side wall. If the furnace uses regular (metal) vent pipe you can go through the roof or run the pipe through the side wall and up above the roof (pipe’s height above the roof depends on the roof’s slope). If your roof has an overhang (soffit) you’d need to clear it with the pipe or go through it.
Pipe must be properly secured along its entire run and double wall (B-vent type). The room requires ventilation / fresh air supply for proper combustion (gas burning) – https://checkthishouse.com/3518/chicago-condo-inspection-combustion-air-requirements.html