I'm thinking of using timber I beams for my new shed roof (in
place of solid timbers). A couple of questions:
 Are there any problems with using these in a shed
environment, where they won't be exposed to weather, but will be
subject to higher humidity than they would be in a house.
 I can't find any span tables for I beams - I need to span
6m, only end supports, and only a box profile roof at 6 degrees.
Any idea where I can find a suitable table?