fireblocking

[dug]

20 by 30 1 & 1/2 story with 10 ft. walls- is fire blocking required on the entire wall, or only in loft area?

[PEG688]

  Only at the loft and any associated stair well walls.

The other variable would be at any joints in your wall sheathing, the "Nail all edges" part of the IRC 2006 code.

Also the type of siding you may choose, vertical board and batten / vertical channel and other vertical types of siding  like to have some horizontal blocking.

   

[dug]

Thanks PEG, that's what I thought. I am blocking all sheathing edges as you suggested.

[PEG688]

  10 feet is the normal call out for fire blocking, or "every ten feet" for wall in excess of 10'.