sistering floor joists

[John]

Hello,

I have a space that is 12' x 20' x 8' that I use for a painting booth. It has 2x6's #2pine 16"oc for the ceiling joists. I notice on span charts that 2x6 span is only 9'6". I would like to use the space above for storage and wonder if I sister each with another 2x6 would that suffice for load at that span.
I don't want to put posts in the spray area and I have plenty of 2x6's from another project to sister them all. I know I could sister 2x10's and not worry because they are rated for that span but why buy them if I can use what I have?

Any help would be appreciated
thanks,
John

[Rich]

I believe that would give you some additional weight holding abilty. Not sure how much but your probably looking at something like 15-20 psf additional. When you sister them make sure they are spanning to a point of bearing (3" minimum) and that you nail them at then ends (3 - 12d) and every 3' with the same nailing pattern. One row only of 3 -12d nails.

[Sophist]

I would also recommend using subfloor adhesive as well. This will basically create "one" member and help resist deflection.