Modifying Floor Joists

[Nuche1972]

I have a 1960's ranch with 2x8 floor joists. Basement floor to bottom of joists is only 7 feet. A bathroom in the basement has heating and air ducts running across perpendicular to floor joists leaving only just over 6 feet of head room. I would like to modify this situation to give me more head room. My thought is to header off the section where the bathroom is and move the ducts up to get more head room. The areas on either side are unfinished so the span would be less than 10 feet. any ideas? Also there are a couple of taps from this trunk line in the bathroom so the header would have to be open truss.

[pushkins]

Heading off an area is usually for openings carrying no load, like skylights, stairway opening etc...You have a floor load above these joists so you cannot simply header off these joists, what would carry the above load ?

If you move the duct work up into the headed off joist area your going to have a 90 degree bend getting up into it, a 90 degree bend transitioning to inside the floor joist area and the same again on the way out of the new area, that's 4 x 90 degree bends, you might find yourself in some serious heating and cooling deficiencies, have you spoken to your HVAC guy yet ?