Expert: Bruce E. Johnson - 10/23/2008

Question
my boss wants me to add an attic to a room in his clinic, I know better but would like to ask professional opinion, we have a 30' wide by 25' length we have 2x6 running across the width 30' they are spliced in the middle, and are 24" on center, at 15' there is no load bearing wall underneath joyces are sagging, there is already storage up there, he would like me to add whatever it takes to make it work please give me your opinion

Answer
Hi Craig, If you have a decent roof structure above the ceiling joists you might be able to suspend part of the ceiling weight from the rafters at third span.  You have to be careful in this method if the roof structure or the structure above is not capable of supporting the extra weight.

Thirty feet is a long span for spliced 2x6 even without added storage on top.  If your rafter system is so designed that it is capable of supporting a live load of 30 pounds or more then you should be able to hang the ceiling from the rafters.  I don't know how your roof is designed so I am not able to comment on the load bearing capabilities that it may have.

If you decide to do this you can use 2x4 struts connecting the ceiling joist to the rafter or in some cases you can use wire.  If the ceiling is already sagging then as you attach the struts you have to push the ceiling up and hold it in place while you make the attachment.  This is generally done with a 2x4 jammed into place from below.  I usually make up a T out of 2x4s to the height that I want and then when it is jammed into place it will hold up several ceiling joists at one time.  

I hope this information helps feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com