I am finishing a basement room which has 4 concrete walls. I would like to put the cold air return near the floor. What are my options to move the air past the framing header? Cold air return for the upstairs bedrooms run through the ceiling above the room in question, i would like to tie into these returns.
Could I just remove the header in the two cavities that will have the cold air return, if so how would this affect fire blocking?
Where is the HVAC unit ? In the basement or the first floor ? The headers can be removed as long as its a bearing wall. If its a bearing wall then you may need to add some more supports. As far as fire blocking, if a fire breaks out upstairs, your downstairs is pretty much toast anyways.