Okay, thanks. We are using IBC 2003. I found the exceptions to the parapet requirement and this complicates the issue. It appears for 704.11, exception 4. we would have to created a 1 HR protection for any roof trusses and the sheathing that run parallel to the gable end wall and protect an entire girder truss that run perpendicular to the wall that is 5'-1" away from the interior lot line. That's a lot of Drywall.
If the building were to be sprinklered, then it appears that exception 6. would allow us to have the 1HR wall terminate at the underside of the roof sheathing
"704.11 Parapets, Exception 6. Where the wall is permitted to have at least 25 percent of the exterior wall areas containing unprotected openings based on fire separation distance as determined in accordance with Section 704.8."
"704.8.1 Automatic sprinkler system.
In buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1, the maximum allowable area of unprotected openings in occupancies other than Groups H-1, H-2 and H-3 shall be the same as the tabulated limitations for protected openings."
Table 704.8 states that 25% of openings with walls between 5' to 10' can be 10% unprotected and 25% protected.
So if the building if fully sprinklered then we can have 25% openings unprotected on our 1HR wall that is 5'-1" away from the interior property line, and take 704.11 Parapets, Exception 6?