Relocating main trunk

[tecumseh18]

The main trunk and cold air return run right down the middle of the basement ceiling of my semi-detached 2 1/2 story solid masonry house. To make my basement useable, I'd like to move both to the side, ideally along the common wall (which is double brick).

My heating guy originally said I could put the cold air return along the wall, and the heating trunk on the ceiling next to it to create an L-shape. But his sheet metal guy now says we can't put the cold air pipe along the common wall, that the gas company won't allow it (I'm also switching from from oil furnace to high-efficiency gas at the same time).

Is this true? Why should it be a problem? Solutions? The basement is only about 6' 3" high from the concrete to the joists, so I really want that ductwork off to the side.

[imeduc]

Call and ask code there what you can and cant do/

ED

My mistakes dont define me they inform me.