Multiple Plane Truss

[dchaley369]

Having worked in the truss industry for years it was very common to truss multiple planes. For example, the main house has a 10/12 pitch but the porch tied to is has a 4/12 pitch. Is there a way to get Chief to do this? If so how?

 

9 -11x Mac Version

i7 core, 8 Gigs, SSD

 

 

[Chopsaw]

Yes that is not a problem for Chief as it simply builds the truss between the ceiling and roof planes.  Multi pitched roofs are auto built based on the Roof directives in the wall DBX.  Piggyback trusses however are a little more complicated.

[dchaley369]

Thanks Chopsaw, do you know if there is a video that I can watch? I search the Chief help ones and didn't turn anything up.

 

[Chopsaw]

Take a look through here and then hit us up if you have further questions on specific situations.

 

https://www.chiefarchitect.com/videos/playlists/146/roof-framing.html?playlist=93

[GeneDavis]

Any stepdown truss is dealing with multiple roof planes.

 

Please post the question more clearly.  It seems like you are referring to something else here.

[dchaley369]

Thanks for all the help folks. Take a look at the pict for a general understanding of what I am asking if Chief can do.  

Can Chief make one truss instead two when there are multiple pitches or planes involved? 

Thanks

Edited October 1, 2019 by dchaley369

[Chopsaw]

5 minutes ago, dchaley369 said:

Can Chief make one truss instead two when there are multiple pitches or planes involved? 

Thanks

 

Yes absolutely.  Just remember that Chief does not do the engineering and it will depend on the truss manufacture if they will build a design you come up with in Chief.  Since you are the one with manufacturing experience, I am curious if that is a practical design or would it require support at the pitch change?

[dchaley369]

Being that this is an attic truss, yes it will require load support for the reaction but not at the point of pitch change. They will engineer the truss to pass reaction at the wall between the the 4 season room and the living space as it is a load bearing condition. 

 

You are right the manufacturer must design the truss as the liability is on their shoulders and nothing drawn in Chief will even begin to meet the engineering needed.

 

So, how do I get Chief to give me a reasonable depiction of the truss automatically? 

 

I can draw these in but I would rather not if Chief can do it reasonably well.

 

Thanks

 

 

[Chopsaw]

2 minutes ago, dchaley369 said:

So, how do I get Chief to give me a reasonable depiction of the truss automatically? 

 

I can draw these in but I would rather not if Chief can do it reasonably well.

 

Do you have a plan file with your model yet or is this still at the hypothetical stage ?

[Chopsaw]

Just reading through the Attic Truss information it may not be possible to do automatically. However that does not mean it can't be done.  Chief can define the envelope but you may need to do the webbing pattern. If you open the Truss Detail and unlock the Framing, Roof Trusses layer you can work on the webbing manually.  You will need to use existing members and edit and rearrange them or copy within the same detail. Angles can be mitered using a general framing member and the Trim and Extend tools.

 

https://www.chiefarchitect.com/support/article/KB-00933/creating-an-attic-truss.html?utm_source=Chief+Architect+Premier+21+x64&utm_medium=software&utm_campaign=Resource%3A+faq&utm_content=Error+ID%3A+272003072

 

Here is a quick and rough proof of concept demo.

 

[GeneDavis]

Why would one need to do this, when the truss outfit only needs the plate geometry, the ceiling geometry, the heel heights, overhangs, and pitches, and her Mitek (or other) software goes to work.  All Ms Trussie has to do is place the girders and the overbuilds, the rest gets generated by the software, including the webbing, of course.

 

So why must you do what Mitek does?  Are the trusses exposed, i.e., are they architectural?

[dchaley369]

Chopsaw, Thanks for the info, already did that yesterday. I was just wondering if Chief could do it automatically. But as I suspected it cannot and I understand why.

 

Gene, No offense taken but "Ms Trussie" is a male, LOL. To answer your question of "Why would one need to do this" is so the Customer, Codes enforcement and the Builder all have a good idea of what is being built. Yes, Mitek, Apline, Eagle or whatever software that is used to design the trusses really do all the work. Yes I could do a much simpler drawing but It really is a matter of being a grade above the competition. 

[Alaskan_Son]

I find it useful to get a pretty good feel for how I would like the trusses designed so that I can adjust the design accordingly as well...bearing walls, point loads, beams, feasibility, etc. 

 

The plan above for example...It wouldn't actually work around here.  The truss manufacturer won't build trusses anywhere near that tall, and our snow loads wouldn't allow for the truss even if they did.  In addition, piggy back trusses wouldn't likely work either since the trusses below wouldn't be sufficient to carry the load. 

 

I'd much rather catch all the potential problems myself early on in the process then wait till trusses are drawn up and then have to totally re-design the project.  

[dchaley369]

Michael, snow loads are snow loads and they do limit what can be built in areas.  I checked with the truss manufacturer to see what would be required. I was told the top chord needed to be 7.25" and the bottom chord needed to be 11.25" to achieve the attic space requested.  When I entered the 7.25" top chord Chief didn't trim the trusses for the boxed eaves. Just wondering if anyone else has run it this. 

[robdyck]

2 hours ago, dchaley369 said:

Michael, snow loads are snow loads and they do limit what can be built in areas.  I checked with the truss manufacturer to see what would be required. I was told the top chord needed to be 7.25" and the bottom chord needed to be 11.25" to achieve the attic space requested.  When I entered the 7.25" top chord Chief didn't trim the trusses for the boxed eaves. Just wondering if anyone else has run it this. 

Just curious as to your solution for insulation with a 7.25" deep top chord? And your initial example showed a 20' plus span for the attic truss floor. Even for D-fir that's pushing it.