deck stairs that fan out
I am constructing stairs off of a deck 84" in height. The customer wants the stair to start at 5' width and expand to 8' at bottom ( 7" riser, 12" treads, probably 7/8 steps).
The treads will be constructed out of 5/4 trex accent decking ( 1'' thick, 5 1/2" width ). Two planks together, 11.5" tread.
I am looking for a plan to construct the framing for this stair. I plan on using 2 x 12 for the stringers, but am unsure how to disperse the load as the stairs get wider to eventually reaching 8' at the last tread before you step onto a concrete pad. I believe I should have no more than 12" between stringers to prevent sagging using the trex as treads.