We're putting in a new flue pipe for our existing woodstove. The original one had a flue liner that stopped several feet short of where the hot gases entered the chimney.

Several sources have stated that the woodstove operates most efficiently if the flue runs straight up from the stove.

There's a second-floor floor joist directly above where the woodstove would vent. Should I go ahead and cut a headers, or is there any reason to consider offsetting the flue?

Thank you!