This is probably a handy link for any Indie developer using a portal based system
I use to use this script. I can be worked with Torque, and other engines.
Boadle it does have a flooring system, and I believe since its BSP rule based it will automatically UVW, or so is my belief, been some time since I looked into it.
I will post more when I get home, may be worth a look until then.
Here ya go boadle the simplest way with no scripts or nothing
Map one story as usual. Clone and place 2nd floor. UnwrapUVW 2nd floor. Move uv left/right/up/down/flip etc. Repeat for other floors. Just make sure that brick lines match from one floor to the next. That’s the most difficult part.