Hi Siliang,

Hopefully i can suggest you something to try.
Try the following option.

[image: Inline image 1]

In the first window of wizard mode try putting immediately above in
the *position
the shell* option and put the below floor in the* reference shell.*

And to have one roof try the following option for ground and first floor.

[image: Inline image 2]

In third window of wizard mode for* roof construction* try putting no
exterior exposure (which is red.). This can make the floors interior.

I hope that this can help you.

Thanks,
*Sharad Kumar*
*Engineer (LEED-AP- BD+C)*
*Green Horizon Consulting LLP.*
*Gurgaon*
*India.*