Truss bottom cord lenght


JamesR
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Hi folks,

 

I have a 24' wide building I'm trying to generate an attic truss over. Is there a setting that controls where the bottom cord of the truss bears on the top plate? In the left tab below, I would like the top cord/bottom cord intersection to be on the outside of the main framing layer (left side of the 2x4 wall). This would of course lead to a 24' length for the dimension that is 23'-6 3/8" now in the right tab. What am I missing here?

 

Thanks,

--Jamie

 

image.thumb.png.82f599548900579f17717f44b235e9f0.png

Two Story with Porch - Truss.plan

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There is a setting in the Build Roof DBX  Roof> Specifications> Select "Trusses (no Birsmouth)"  for truss roof construction.

You may also need to add a little bit to your "Roof Height" on the same page so that your overhang does not get hung up on your wall sheathing if that is installed first to the top of the top plate.

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5 minutes ago, glennw said:

I just deleted your truss and drew another one, which drew correctly.

 

Not really Glenn.   It appears you have a 3 1/2" top chord which it seems is the only thing that chief recognizes?

 

I thought the no Birdsmouth setting worked for trusses but apparently not all of them.

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7 minutes ago, solver said:

Setting truss defaults correctly, then placing one, it's correct.

 

That looks better.  Did you deselect "Ignore top floor" because it would not work for me until I did that but not sure why ?

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Hey everyone, thanks for the quick replies. 

 

Chopsaw - I have the no birdsmouth checked in the defaults, but doesn't seem to make a difference. 

Glen - I've deleted and recreated the truss several times, but same thing happens...definition of insanity? :)

Eric - Do you have a complete screenshot of the dbx? I have my options setup as shown, but it is still bearing on the interior of the top plate.

 

As for the "Ignore top floor" option, I'm following CA's KB article about creating a loft area, which instructs to select that option when building the roof planes. Not sure how I would get the FROG otherwise.

 

Thanks,

--Jamie

 

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9 minutes ago, JamesR said:

Chopsaw - I have the no birdsmouth checked in the defaults, but doesn't seem to make a difference. 

 

Yes I commented on that before checking your plan file.

 

10 minutes ago, JamesR said:

As for the "Ignore top floor" option, I'm following CA's KB article about creating a loft area, which instructs to select that option when building the roof planes. Not sure how I would get the FROG otherwise.

 

I think I had to turn Auto Rebuild Roofs back on but it did not seem to work until Ignore Top Floor was off.

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Thanks Eric, Chopsaw, and Glenn. I got the truss to form correctly on the top plate.

 

New issue is I'm trying to change the two out-most trusses to dropped gable end trusses, and they change from the attic configuration, but not to what I would expect. They have this big honking hole in the middle like I have a window there, but there are no openings on the gable wall. I suspect its something to do with the little attic walls I have on the Attic floor, then opening is approximately the same width as those walls, but I'm not sure what settings would affect the truss framing like this. Without any windows, I would expect the end truss to be straight studs 16" o.c. Any ideas?

image.thumb.png.301950c634f89fc4a2020fbbdd03f8f4.png

Two Story with Porch - Truss.plan

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Hi James,  Take a look at this plan file and see what you think.  I deleted your attic walls and made the gable end walls balloon through and gave the gable end walls a new definition without framing.  Also not sure that the end trusses need to be designated as Attic Trusses.  Not sure why the conflict exists but I think this configuration avoids it.

 

Two Story with Porch - Truss Chopped.plan

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  • 3 weeks later...

Well, life got in the way of things for a few weeks, but I finally had time to get back and look at this. Chopsaw - your method looks to generate exactly what I would expect for an end truss, thanks. I tried everything you mentioned except the new wall definition without framing, and I am still getting a truss that has a big opening in it. The change in the wall definition to remove framing seems to work, but deleting the framing layer makes the wall thickness ~1". I'd like to avoid having a workaround that deviates from reality so drastically. 

 

Anyone have an idea why the end trusses are generating like they are? Another workaround that I can think of is having the gable walls balloon through (as Chopsaw mentions) and have them frame traditionally. However, this does reflect how the building will be built, and the end trusses wouldn't show up in the truss schedule, which I would like it to.

 

Appreciate the input.

 

Thanks,

--Jamie

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33 minutes ago, JamesR said:

Another workaround that I can think of is having the gable walls balloon through (as Chopsaw mentions)

 

I believe that was just the wall sections covering the end wall truss that I was referring to.  No framing just sheathing and siding.

 

36 minutes ago, JamesR said:

but deleting the framing layer makes the wall thickness ~1". I'd like to avoid having a workaround that deviates from reality so drastically.

 

How would you build that in reality ?

 

38 minutes ago, JamesR said:

I am still getting a truss that has a big opening in it.

 

I believe it does work in other situations and likely this one should be sent into tech support so they can figure it out.

 

Normally you can have a regular wall definition there and that truss just deletes the framing but I usually still put the thin wall on the drawing so it does not get framed accidentally before the trusses arrive.

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