DJP, thanks a bunch, I believed that worked for the garage. Here are the steps I performed:
1. Plan, Default Settings-Floor-Edit and set the rough ceiling height to 97 1/2".
2. Plan, Default Settings-Foundation-Monolithic Slab.
3. Done
4. Built a structure and then attached another structure.
5. Main Room, Open Object-General-Room Type-Family and left all settings like they were.
6. Garage, Open Object-General-Room Type-Garage and left all setting like they were.
7. It now looks like the garage floor is 4" lower than the main house floor, so it worked, thank you!
However, when I added some railing for a front porch, and made it Room Type-Porch it appeared to be same level a main house floor, so I changed it to Room Type-Garage and it lowed it 4", which is what we currently have.
I'm trying to duplicate our current home so we can remodel.
Thanks again!!