Forums >> Revit Building >> Technical Support >> Warping Deck/Sloping Joists

johnnyutah54

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Joined: Tue, Jun 19, 2007
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I have a very large building that will have warped structure to achieve drainage (as opposed to using crickets to provide the slopes). The roof has been created with the appropriate deck bearings at the ridges and at the drains. I need to add joists to the underside of the deck, but I can not figure out how to get joists to warp.  To describe it basically, imagine you have a roof plane that is rectangular 10' x 30'. The elevation on 2 short sides and 1 long side are all at 0". In the middle of the long side, the elevation is -20". What I need the structure to do is maintain that 0" elevation along one side and then slowly march down from 0" to -20" and then back up to 0".

I figured beam systems would be the way to do that but I can't figure out how to make it work. Adding reference planes won't work because for each small section of roof there will be a minimum of 3 separate planes, which joists crossing the planes. I am attaching a small image of a portion of our roof.

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WWHub

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Joined: Tue, May 16, 2006
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I am working on a project now where we were warping our deck.  The interesting thing about Revit is that it will really tell it like it is.  Using seperate roofs for the deck and insulation and after turely warpng the surface using the modify sub-elements to set the dropped corner elevation, we used the spot slope annotation tool to see what slopes we really got. If you try this, you will be srprised at how flat the roof is in the corner bounded by two flat sides.  You almost have to go a third of the way on the diagonal before you see an exceptable slope.  Funny thing is that we never saw this when we CAD drafted.

Our joists do set on beams so no problem defining where they were.  Are you using bearing walls and that is why the problem?  Not sure I have an answer but I don't like warped decks so much any more.

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mbsteve

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Joined: Fri, Sep 22, 2006
759 Posts

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