CrossFireDesign

Thank you, Thank you, To your kind voice of experience.
In the Materials section of "Floor > Edit > Floor Structure Definition > Material layers", and, even though you were kind enough to literally point it out the other day,
I clearly did not grasp how that dialog panel worked.   I simply did not realize, or even notice, that the  "Structure> framing> type" would switch dynamically to become associated with the layer being clicked on above.  When I saw "Lumber" noted below I simply assumed it applied only to the "Framing 1" layer and further assumed I already had it set correctly. Now I'm finally getting a better grasp of the relative nature of the software.
By the way the  4-in-12 Slope was intentional,  This file was prepared simply to try to understand the working applications of the defaults. The slope is one I got right the first try.
My next task to more clearly understand the dominance of "Defaults" vs "Room" vs "Framing" settings, and your video did a good job of helping me get started there too.  
I really appreciate your patient explanation.
 

My test based on Rookie65 suggestions;
1) On house wall above the stem wall in question; selected for "Wall specification"> "General" and changed "Thickness" from 6-15/16" to 4.5" ..  Stem wall gap remains.
2) Restored "Thickness" to 6-15/16"
3) Selected Storage room sidewalls that intersect with House wall  changed "Thickness" from 6-15/16" to 4.5" .. Stem wall gap remains.
4) Returned all Wall specifications back to "Siding-6" 
Solution used as Suggested by Rookie65
5) Changed Room Specification>General> Room Type to; "Patio"
6) Changed Room Specification> Structure> Floor to; "floor under this room"  Result - No more Stem wall gap!  
7) Changed Room Specification> Absolute elevations> Floor > to  "0" then; "-10" then; "-14" then;  "-20" then back to "-14"    Result = floor moves up and down at will and no stem wall gap occurs.
I must have read a hundred pages and viewed a half dozen videos and don't recall seeing anything about this.  Now I can move on to the next unknown (for me)
Great Job Rookie65 !  Thank you Kindly. The results are repeatable and this is just what I need.
 
 

My Question was "can a NEW "Room Type" be added?"  According to Nathan B., in technical support, the answer is; NO, users of HD pro 2023 may not add new Room types.  The number of room types is fixed in the program.   My copy of HD Pro has 32 Room types. 
We discussed two example bedrooms; One with hardwood floors and one with carpeting. In this example Nathan agreed with Rookie65 in that a given named Room Type; "bedroom" in this case, can be first used in one bedroom to specify, for example; a hardwood floor, and then the same named room type can be modified for a second bedroom to specify carpet.  The differing attributes are stored in the design file. The default floor for the named type "Bedroom" remains Carpet unless and until changed by the user say if a new Design is started and there is a need for hardwood flooring again, or perhaps to apply tile to a third bedroom in the first design file, Nathan also agreed that for a given design file an unused room type such as; "Bonus" or "unfinished" could be renamed in effect providing a second bedroom default, However, the total number of Room types does not increase only their names change and related attributes when changed by the user.
Nathan also investigated and found that earlier versions of  Home designer Pro, as shown in the training videos, indeed had multiple bedroom types; Master, bedroom 1, bedroom 2,  and so on. These were eventually deemed "redundant" and removed, they are now not delivered with current versions of the program. 
Thanks to each of you for your support, and David, Thank you for your quick Video it was very enlightening on changing attributes on the fly, and especially the part about Display options I will be paying closer attention to that.