Thread: building a one hour fire separation wall

I need a one hour separation wall for a studio apartment I'm adding in a former garage. There's a room between the studio and the existing house, so I can sheetrock both sides of this wall easily with 5/8 firecode sheetrock. The fire separation wall is non-bearing. It's only 12' between the exterior walls.

My question is how to get the fire separation sheetrock into the cavity between the roof rafters. It's a shed roof with 2x8 rafters that are parallel to the fire separation wall, but this wall falls in between the rafters (2' o/c rafters, about 10" from one side). The studs could go up to the roof sheathing, but I don't see how to frame it solidly.
a. I don't want to put a 2x4 against the sheathing to nail to because its only 3/4" with a metal roof on the outside and I'm nervous about puncturing the roof.
b. If I put 2' nailers between the rafters and attach the studs to that, the nailers penetrate the firewall.
c. I could put 2' nailers laid flat just under the roof sheathing, but I still have a penetration.
d. ????

Number c. seems best so far, but does this meet code for separation? Is there another way to do it.

Thanks,
Bob

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Pictures of the attic/roof so we can understand you issue.

I don't have a picture yet, but let me simplify the question. Fi

1. Does a 1 hr fire separation wall need to extend to the underside of the roof sheathing? (I'm assuming this is yes). Note: This is in a shed roofed structure, so sheathing is 3/4" T&G with metal roofing over it.

2. How do I attach a top plate to underside of T&G without risking puncturing the roofing?
Note: the fire separation wall lies parallel to and in between the 2x8 rafters.

Thanks

I'm not sure but it sounds like if you build a fire-rated "box" with the drywall that covers the walls and ceiling you should have your fire seperation without messing with the roof. A picture would be nice for sure!

Thanks for the response. Sorry about photos. But you can picture this as stud wall that is parallel to the 2x8 rafters for the shed roof and is positioned so that it comes up in between two of those rafters.

Now, my remodel contractor friend has said it can be treated the same as an attached garage. He says the firecode sheetrock (on both sides of the stud wall) only has to go the ceiling level and then a regular 1/2" sheetrock ceiling is all that's needed. He says he has not had to build a garage firewall all the way to the roof sheathing -- just to the ceiling level.

I probably have to check with the inspectors, but I had previously understood they wanted fire separation wall to reach up to the roof sheathing.

thanks again.
bob