Expert: Bruce E. Johnson - 3/21/2010

Question
Just bought 30'wide x 40'deep building.Barn roof.11' ceiling 1st floor, 8' ceiling up top. 2x4 walls 16" centers. Ceiling joists are 2x6s butted with 8' scab tie. Ceiling joists connected to roof rafters. Roof rafters are 2"x6" with 24" centers. I would like to use the approx. 20'x40' upstairs while keeping downstairs open (no walls). Can I split existing floor joists with 30' manufactered lumber? Any other ideas? Sorry if terminology is off, as I'm an industrial electrician and don't deal with this much. Thank you in advance.

Answer
Hi j rayson, Of course you can.  The ceiling joists you have right now won't make it for supporting any weight upstairs but sure, there are manufactured joists and or girders that can span the 30' no problem.  What you might want to do is attach a ledger on the walls for the girders or I-joists to sit on.  They will be taller than the 2x6 joists you have in place right now and it looks like you would want as much head room upstairs as possible.  So by installing a ledger at the proper elevation you can make it so the new joists are even with the tops of the existing ceiling joists.  This will decrease your head room on the first floor a little bit but will give you a full 8' of head room upstairs.  I hope this information helps, please feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com