IBC requires a fire wall between townhomes. I seem to be finding a reference to the use of "double walls" - or two separate 1-hour walls, along with several images of this detail. Each framed wall has a layer of 5/8 gypsum on either side of the framing (four layers of gyp total, two on the exterior side, two on the gap side). My question is this - is it even possible to build? Sure you can build one of the walls and fire tape/caulk it, but the second wall - how do you install the gypsum on the interior (gap side) of the framing? I know there are other options with shaftliner panels etc. - but is 4 layers of 5/8" on both sides of two walls even possible to build correctly?