I am installing a range hood and due to a ceiling joist in the way, I have to offset the ducting going through the ceiling by about 3" from the center of the hood. I have to do this within about 30" of height from the vent hood to the ceiling. The easiest thing to do would be to just use semi rigid ducting however from what I've read this is considered less than ideal because of potential for grease to build up on the ridges. Though I think if I stretched it out 100% it would minimize the ridges. I don't have enough room to put elbows in and that would offset it too much anyway.
The options I can think of are...
- Just use semi-rigid ducting
- Use rigid ducting for the first few feet (where maybe grease buildup will be the worst), then go to semi-rigid through the ceiling and back to rigid in the attic.
- ??? I have no idea.