Multiple Foundation types under one building/ How to lower a room onto a slab?

[BoDay1]

Hello,

 

I'm drafting an existing residential care facility in preparation for a remodel.

 

Most of the building is on a perimeter foundation with the sub-floor about 24" above grade.

 

But one room, The Staff Quarters, is built on a slab about 4" above grade.

 

What is the most efficient way to make this modification?  Should I have made the modification before drawing the full exterior of the building?

 

Attached is a snip showing the floor plan with the Staff Quarters labeled.

 

Attached is also a snip showing the basic roof lines... after lowering the staff quarters the roof for that room should fit just below the eave of the main roof line.  Note that part of the staff quarters is under the "main gable roof" and part of the staff quarters is under the low-pitch shed roof.  I realize that may not be logical but that is how the existing building is built.  But the floor height for the staff quarters is all the same and all on the slab.

 

I've also attached the project.

 

Thanks for any help/ advice.

 

Bo Day

Aguilar Existing Floor.plan

[solver]

Change that room to have a slab foundation and lower the absolute heights. Build the foundation.

[BoDay1]

That sounds easy but when I do that I don't know how to force the program to stop building stem walls.

 

I know how to choose a slab foundation and I know how to set the floor height at -20" (the floor height for the main structure is 0").  But it doesn't simply give me a flat slab... it creates  a slab at the height I want but insists on also giving me a stem wall and it just goes back and forth.

 

I want a slab with a footing and no stem wall.

 

There is something I'm missing.

 

Bo

[BoDay1]

Ok... I got the foundation to behave.  Thank you.  It just seems harder than it need to be.. but I suppose that is my inexperience.

 

Thank you.

 

Bo