cantilevered plywood subfloor

huangyhg

cantilevered plywood subfloor
please don't laugh, but i have a question regarding a very small cantilevered plywood subfloor.  i have a condition where i have a 6" gap between my structure (wood truss) and an adjacent building.  there will be an expansion joint between the two structures, but with a 6" gap, the joint material becomes very expensive.  i'm hoping to cantilever the plywood subfloor out 4" to 5" so that a smaller gap to bridge exists.
the contractor is using the advantech 3/4" subfloor material.  does anyone know of any information that is avaiilable to 1) determine whether a plywood panel is allowed to be unsupported at its edge and 2) determine the max cantilever distance.
any help would be greatly appreciated.
thanks
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one thing you can do, in my opinion, is to cantilever out some 1x flat   
is this 5'' - 6'' cantilever carrying any real loads??  not sure i understand the arrangement.
if no loads --- make sure it is weather protected and just go with it...
yeah, the plywood would rarely see loads here.  it runs parallel with a corridor (in my building) and an exterior wall of a parking garage.  
to give you a better idea, there's a picture at the link below:
as long as it's not a hazard where someone could get their foot stuck in there, i wouldn't worry about it.
the gap has to be closed with an expansion joint materal for a fire rating.  as it is now, you basically have a chimney in which fire can shoot up between the floor system and the adjacent brick/concrete wall.
my reason for cantilevering plywood would be to minimize this gap.  a 6" expansion material runs about $100/lf accorinding to my contractor.
i don't think cantilevering the plywood a couple of inches is a huge deal, but i wanted to get some other thoughts on the matter...thanks everyone!