Made huge progress yesterday. Before my little guy woke up for his first day in 3rd grade, I found myself at Home Depot at 6:30 a.m. gathering more supplies to go to work on this riser.
I started by laying down 3 rows of the acoustic rubber mat and taping them together with black duct tape
Got the riser all framed with 2x10's as the outer base and 2x8's as the center studs. Once I was finished, I lifted the side closest to the screen onto a piece of PVC, then lifted the back end and slid the whole platform into place.
I cut many strips from the roofing felt, folded them to make the riser level with 0 squeaks or wobbles anywhere
Framing all finished. The steps will be 2' deep X 37.5" wide which will fit 2 seats between perfectly with 2" to spare on each side. The step lights and front row seat outlet is all wired and ready for insulation
I did 2 layers of fiberglass in each cavity.
First layer of 1/2" OSB is in place
Next I sandwiched roofing felt between another layer of 1/2" OSB