BKraengel

Ceiling Structure Vs. Floor Structure

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Hi All,

I am confused by Ceiling Structure vs. Floor Structure in the Structure panel of the Room Specification dialog. What is the difference between the Ceiling Structure of the room below and the Floor Structure of the room above? For example, in a conventional platform two-story house, the floor structure of a 1st floor room is either a platform or a slab. If a 4" slab is used the floor structure is 4". The rough ceiling of that room is usually the undersides of the floor joists for the room above. I would say that is not a Ceiling Structure, but the Floor Structure for the room above and, therefore, assign a 0" Ceiling Structure to that room. Is this correct?

I really get confused whem we move up one level to the 2nd floor. The rough ceiling in a 2nd floor room is usually the undersides of the floor joists of the attic room or the undersides of the bottom chord of the roof trusses. To be consistent with what I did before I would again say that is not a Ceiling Structure, but the Floor Structure of the attic room. Whoa! The program seems to be telling me something else!....

If I have specified elsewhere truss roof construction with a 2x6 bottom chord, the program defaults to a 5 1/2" CEILING Structure. In other words the program is telling me it is not the Floor Structure of the attic room, but the Ceiling Structure of a 2nd floor room. Say what? Why did we switch horses in midstream?

Anybody know what's going on?

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The floor structure 2nd floor, is adjusted on the 2nd floor, floor. The floor structure on the 1st floor is adjusted on the 1st floor, floor. 1st and 2nd floor ceiling height and structure is just that. always adjust all ceiling and floor heights from the top down, not the lower to highest floors.

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There could be instances where both specifications come into play.  Upper level room is smaller than the room under it.  Ceiling/floor joists would be determined by the upper level floor joist.  The area with no upper floor above it would switch over to the ceiling joist specification.

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The floor structure 2nd floor, is adjusted on the 2nd floor, floor. The floor structure on the 1st floor is adjusted on the 1st floor, floor. 1st and 2nd floor ceiling height and structure is just that. always adjust all ceiling and floor heights from the top down, not the lower to highest floors.

If you set the ceiling structure of the first floor to say, 2 x 6 joists and the floor structure of the second floor above to 2 x 8 joists will the 2 x 8 floor joists above override the 2 x 6 joists of the ceiling below? I always make sure they are the same. Is that necessary? Correct?

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If you set the ceiling structure of the first floor to say, 2 x 6 joists and the floor structure of the second floor above to 2 x 8 joists will the 2 x 8 floor joists above override the 2 x 6 joists of the ceiling below? I always make sure they are the same. Is that necessary? Correct?

 

Yes.  The floor joists will override the ceiling joists.  At least in all my experience.  I personally never make sure the ceiling framing settings match the floor above...never seemed to be a need for that. 

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Yes ,Larry just like when you add trusses and the conventional framing goes away.

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I think I know which question you are answering a 'yes' to Perry - but not sure.

 

Would it be desirable to have the floor joists of the floor above over ride and actually change the ceiling joists of the floor below? Or would that take away an option or two?

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I think I know which question you are answering a 'yes' to Perry - but not sure.

 

Would it be desirable to have the floor joists of the floor above over ride and actually change the ceiling joists of the floor below? Or would that take away an option or two?

 

What option would it take away.  You can't have ceiling joists and floor joists occupy the same vertical space.  It only makes sense that floor joists override ceiling joists.  

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For the OP - I often use 10' ceilings in my custom home designs, but I specify to frame down ceilings in small areas to 9' or even 8'.  Floor and ceiling specifications are both very much needed.

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For the OP - I often use 10' ceilings in my custom home designs, but I specify to frame down ceilings in small areas to 9' or even 8'.  Floor and ceiling specifications are both very much needed.

Yes, F&C specs are needed to be MORE FLEXIBLE. Using layers in the CEILING DBX works for FULL SOFFITS, but if the soffit had some shape to it, if gets a bit tricky.

JPC, you brought up a good point.....

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Yeah Johnny brought up an 'option' I was thinking about but I'm a bit curious Scott, do you ignore the ceiling framing of the floor below and only set the floor above's floor framing? Or do you ensure both are the same?

 

...and any of it only makes in the world of Chief. Real world neither a floor or ceiling joist 'overrides' the other and in fact they are always the same size if they occupy the same space which is why I thought (not Chief think but real world think) that they should be spec'd the same in each dbx If not, then I'm learning.

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If there is no floor above then it's a ceiling, it changes to what it needs to be. I wouldn't want to change both.

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Hi all,

I am working on a room where I want the ceiling to show the open steel joist framing for the floor above. I have made the floor above and framed it. I have turned off the check box for ceiling on the room. When I take a camera view of the room, the ceiling just appears to be dark space instead of showing the joists. Any suggestions? I am working in X5.

 

Thanks,

Lee

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