Interior 8' ceiling height room within a room with 18' exterior walls and ceiling

[Colesb]

Just started with Home Designer Pro 2023. I'm trying to help my local Volunteer Fire Department with preliminary layout of a new firehouse to present to our Board of Supervisors. They have requested

 

to have 5 rooms in the bay area with 8' ceilings. The bay area has 18' ceilings. How do I get the interior walls to match the 8' ceilings? I'm completely new at this, so any advice on my topic or how I should present my questions in this forum will be greatly appreciated.

[Colesb]

Thanks for your info. Hopefully I got my signature as you suggested. I'll check out your other suggestions and get back to you. I have "Flat Ceiling", "Roof Over this Room" and "Shelf Ceiling" checked in the structural properties of these rooms. That is what gave me the configuration in the screen shot in my original post. When I just checked Shelf Ceiling, I got a ceiling at 18'

[solver]

I just tried using the shelf ceiling and see just what you are seeing.

 

Looks like you will need a 2nd floor.

 

Two ways to do it. 

1) Build a 2nd floor only over the shorter rooms. 

2) Build a 2nd floor over the entire building. Use an Open Below room on the 2nd floor over the larger room.

[Colesb]

Thanks for your help. I think I like option 1 better. Hope I'm not going to wear out my welcome but I'm going to post another question in a minute.

[Garybills]

I used the 2nd floor with invisible walls over the 5 bays and open below over the garage area.

[Colesb]

Thank you very much for your input on this. I will try your solution later. As I am very new at this and right now I'm just trying to help our Volunteer Fire Department get a layout for submittal to our Board of Supervisors for their approval. After that they will get a real architect to properly design this building. What I did to get the visuals was selected the wall surfaces that extended above my 8' roof and pulled them down. That left the posts extending up. I selected them and it would not let me pull them down, but when I pulled them along the wall, they disappeared. I'm pretty sure that the structure is not correct and would not be acceptable for a real design, but for now this will be ok. I also think it may be better to have these rooms outside the big structure. This will make the bay area with 18' walls smaller. These rooms would then be just outside the bay area and would have a shed roof.