I am not sure how well I will be able to describe this challenge (or even represent with snapshots). When we built this house in 2011, we put in a 2 step sunken family room on the first floor. The 2nd step was a suggestion from the builder with a recommendation to sink the corresponding floor in the basement. I thought this was a cool idea. Since the house has been built, I have been struggling with how in the heck I would finish this space someday. Someday has arrived.
So, the issues are as follows. In the perimeter of this sunken basement floor, there are 3 columns. Actually, there are 4, but 2 are in the same place and will get boxed in together. I would prefer to sink 2 of them into walls to make them disappear.
One of the many things that have baffled me along this way is how I transition flooring from a concrete slab to another concrete slab. I plan to reduce this problem by closing in 2 of the walls and half of the third. So I will have a step down that is about 8 feet wide. The thought now is carpet in the lower area and laminate in the upper. I figure we can wrap the carpet up the face of the concrete, but I am not sure what to do with the edge of the laminate! I need to decide on a flooring and see if they recommend/support the gluing of a bullnose stair edge of some sort. The problem is the distance, I have seen some that are 3-4 feet long, but nothing that will do 7-8'.
From there, I plan to run walls on the transition lines. But how? I will post some pictures below. If I run the walls on the top of the steps, it is easy to pick up the columns. But, how do I finish the walls in the inside of the sunken room? If I run the walls with a bit of overhang over the step edge, the drywall could just hang in daylight. Would this haunt me? How would I attach base trim. I have considered running 2X6 walls with an inch of overhang and then during some sort of furring strip down the face of the step to attach the drywall. This sounds like a PITA to me, and may not look right. I also considered just doing two 2x4 walls, one high, one low. It will make a thick wall, but will be easy framing. AND the price of 2X6s is almost double the cost of the 2X4s. I have a 9'foundation, so the "upper wall" is close to 9' high. This would further increase the price of the 2X6s.
Here are some pictures. Don't mind the awful mess. I keep moving crap around as I work and I swear the pile gets larger with every move.