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The attached image shows a Scissor truss that is a bit odd. Notice the peak of the ceiling below does not align with the peak of the roof above. This truss does span from the two exterior walls of the house. Not sure if this then causes the drop down section on the right side to become load bearing or not - it does come down to a load bearing wall that separates the kitchen with cathedral ceiling from the hallway with 8' ceiling, but my thought it is that it is simply for the 8' ceiling. Also notice that the drop down portion on the right which serves to mount the drywall for a typical 8' ceiling has no webbing at all - just verticals coming down off the bottom chord of the scissor truss. Lastly, this drop down portion is all 2x4 while the top and bottom chord of the scissor truss is 2x6. you can see from the diagram also the portion that we are wanting to remove so we can 'raise' our ceiling to match the cathedral ceiling in the kitchen. enter image description here

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    Those trusses are typically not triple-bearing, but there's no way to know for sure from a sketch. Are there bearing point indicators (often paper tags) at the lower corner?
    – isherwood
    Jan 14 at 15:32
  • Good question! I will double check but I don't think there are any tags or notices attached to that portion of the truss. Jan 14 at 15:56
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    Probably not load bearing. Is it even possible to support a truss in the middle of a bottom chord? I'm not an engineer, it just seems counterintuitive. Isn't the truss designed so that chord under tension from forces above, provides the right flat and stable shape to the roof? \
    – jay613
    Jan 14 at 16:37
  • How did you get all those measurements? Is the drywall removed? Jan 14 at 16:57
  • We got all the measurements using laser measuring tool and spending lots of time crawling around in the attic. Trying to make the job for our structural engineer as simple as possible (which we hope means as inexpensive as possible). The drywall is not removed - not yet anyway. Jan 14 at 17:07

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The part you want to remove appears (per the drawing) to be non-structural. The lack of diagonal bracing (web members) and the fact that the verticals do not connect coincident to the web connections above are strong indicators that it's just to support the dropped ceiling, and can be removed without issue.

If the trusses supporting your ceiling in the kitchen area you want to match look like the truss here without that part, that's another indication.

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    Thank you for your input. Sadly, we are probably stuck spending lots of $$$ on a structural engineer to say the same thing and provide the official documentation showing that we can make the modifications and remove this portion without concerns. I would like to think they could forgo the costly modeling by simply applying some commonsense first and save us the money, but I do believe in safety first. No need to live in a compromised house. Jan 14 at 16:28
  • Is there wiring and/or HVAC ductwork inside the dropped volume? What is the height of this dropped area above the floor? Jan 14 at 16:47
  • Yes - there is wiring and HVAC in this dropped down space. The height of this dropped down area is 8' above the floor - typical ceiling height. Notice that we do not intent to remove ALL of the dropped down portion - just some. Jan 14 at 17:09
  • Is there any possibility that removing the static load of the dropped ceiling will significantly change the stresses in the cords and webbing of the scissors truss? Is the weight of the dropped ceiling bourne by the truss or are there posts to the floor? Or is the load of the drop down ceiling insignificant? Would the original design of the webbing have taken into account the Jan 14 at 17:39
  • @JimStewart - our intention is to remove the drywall, remove the drop down portion, and then reinstall the drywall on the bottom chord of the scissor truss to follow the existing cathedral ceiling lines. So ultimately not any significant change in the static load. Jan 14 at 18:22
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Those members are not structural and can be removed.

Truss members are either in tension or compression. When a load is added between connection points, it puts the member in “double bending”. That is to say, the member now has additional tension or compression.

To confirm the structural adequacy of the truss without these other members, I’d take your drawing to a local truss manufacturer and have them duplicate a truss that matches your drawing. They have software that can duplicate your drawing and let you know what the live and dead load is on each member of your truss, whether they designed it originally or not.

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  • The 3rd paragraph is really good info! Not something too many folks here have thought of. Thanks for sharing that idea!
    – FreeMan
    Jan 14 at 17:14
  • Often the truss designer wants so much info (slope of web members, etc.) that it’s easier to have them design the trusses for the load and span and just compare the two diagrams.
    – Lee Sam
    Jan 14 at 18:23

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