I have an un-utilized front porch area that I want to open up to my main house area (on the right through the glass door) by building an internal wall as shown below. This will act as a foyer/entry way for my front door which is open to the main house (picture 2). I plan to remove the big sliding glass door and just create an arch way into the main house.

The brick floor is real brick with a concrete slab below it. If i remove the brick, it will be about 3-4 inches below the level of my main floor.

1. Can i build an interior wall on top of the brick? (i assume no)

2. If I have to remove the brick, what are my options to lay flooring? Should i just create a ramp/step up into the main area or do i need to build a subfloor on top of the concrete?

Any other thoughts or recommendations are helpful.