My daughter wants to convert a 10'x12' screened deck off the kitchen into a study/office. The structure is framed with aluminum tubes and beams. The floor is fairly nice tile, but it's about 3.5" below the kitchen floor (just a couple of inches above grade), and she wants them to be flush.

Questions we have are:

1. Can we just place forms around the perimeter and pour another 3" or so of concrete directly on the tile (with prefinished wood flooring to make up the difference)?

2. Can we leave the aluminum in place and use regular framing lumber to make walls (we'd use drywall on a treated 2x4 sill, 2x4 studs and ceiling joists at 16" o.c.)? I'll check building dept about insulation requirements in case we need R19 in the walls, etc (Summerville, SC).

3. We'd like to leave the existing roof in place. Also the existing aluminum soffit (The soffit would be hidden by the new drywall ceiling).

Would appreciate any tips from those with experience. Especially regarding pouring the concrete directly on the tile.

Thanks much.