Cantilevered trusses

[GeneDavis]

The thread's author, BnCKelley, did not succinctly write his or her problem, nor was it better or more clearly posed in the two followup posts he made.

 

Go back and read them carefully.  Do it twice.  I did and wrote up the details of the suggestion, but I've made it clear it should be posted in Suggestions by the person with the need, in this case, ol' BnC herself.

 

 

 

My take on it it is the 4th reply to Michael's in the S forum.

[rgardner]

15 hours ago, Alaskan_Son said:

To anyone following along and/or struggling with this same issue being discussed here,

 

After reading through this thread and some other similar threads on the same subject, I've concluded a few things:

 

1. If you want to see any improvement in this area, you'll need to describe your issue a little more clearly.  The the burden of describing the problem is on you because you're the one having the problem, and if you can't describe it accurately, no one can effectively help you with it.  Plus, Chief can't fix what they don't understand either.
2. This problem doesn't seem to have been brought up in the suggestion forum...at least not that I could find.  If it's not getting reported/suggested then its not gonna get changed.
3. The challenge is a bit more complicated than some are letting on.  For example it was my supposition based on the initial post that the OP wanted to set a specific pre-determined, user-definable heel height at the exterior wall.  This is a perfectly valid way of configuring a truss but would result in variable overhangs depending on the specified roof pitch. The methods I spelled out in my first post were specially geared at ways to set this user defined heel height.  After reading through the thread again though, I'm starting to believe that contrary to the way the question was posed, what was really wanted was a way to FIND that required heel height at the exterior wall.  This is another perfectly valid method of configuring a truss but unlike the first method, it would result in the opposite; a user definable overhang and variable heel height depending on the roof pitch.  There are also other valid methods that would result in a variable truss tail or sub-fascia height but I won't go over those because I doubt that anyone is talking about that.

Anyway, I don't disagree that Chief could give us a better way, but again, the problem needs to be spelled out at least a little more clearly, and needs to be presented that way as a suggestion, either in the forum or sent in directly to Chief.

 

Until Chief gives us something better, all we can do is find ways to get it done using the tools we have NOW.

 

There are several methods we have now of accomplishing both of the main truss configuration methods I mentioned above.  As others have already pointed out, it can be pretty easily done by taking a section view and finding the required numbers, but it can also be done using formulas so that you don't have to take any measurements.  I took the liberty of writing some custom text macros that carry out the calculations for you and have attached them below.  I'll leave them available free of charge for a limited time.  Simply download the macros, Import via Text Macro Management, select the desired macro, click Edit, change the appropriate values, and then copy value(s) from either the New Result or Expanded Macro Value fields.

 

There are 4 macros:

-One for calculating the required heel height or Raise Off Plate Value using a standard Pitch (12 in 12)

-One for calculating the required heel height or Raise Off Plate Value using a roof Angle (45.0)

-One for calculating the required overhang using a specific heel height and a standard Pitch

-One for calculating the required overhang using a specific heel height and a roof Angle

Cantilever Truss Calculators.json

 

Very kind of you Michael to provide this.  Very simple tool and will help me personally as even though I could always able to get it by using the tools we have this streamlines the process.  I personally would like to see the overall suggestion here written up by someone who can very clearly write up the two options so that it can receive the proper attention by Chief.

 

[BnCKelley]

Ok, I feel y'all are beginning to make me sound stupid. I asked 2 simple questions, most everyone at first understood. How can I raise the roof to allow (create) a cantilevered truss and is it possible to set (I spoke the post and it came out sit) the depth of the truss (heel) at the wall? I explained in truss design software, we always used pre-calculated heights for this heel height and the end height of the truss was always the same. Several people responded quickly with great answers, not too difficult either. How much more clear could I have been. Just 2 questions. I don't get it. It seems twisted around and around. I'm not looking for numbers or dimensions. Just methods, like, here's how.... and no you can't or yes and here's where. It's sounding like I can't explain how to make a PBJ. And what the crap, Gene thinks I'm a woman! Solver got it, Michael and a couple others but man this just seemed to go south quick. Again I appreciate all the help and I'd be glad to suggest this to Chief if the demand is there, or anyone else can if you want. Personally I'm still very green with this software and it took me a little while to just find the section elevation I needed. Just please try to give more how to and where details and less criticism. 

[GeneDavis]

9 hours ago, BnCKelley said:

Ok, I feel y'all are beginning to make me sound stupid. I asked 2 simple questions, most everyone at first understood. How can I raise the roof to allow (create) a cantilevered truss and is it possible to set (I spoke the post and it came out sit) the depth of the truss (heel) at the wall? I explained in truss design software, we always used pre-calculated heights for this heel height and the end height of the truss was always the same. Several people responded quickly with great answers, not too difficult either. How much more clear could I have been. Just 2 questions. I don't get it. It seems twisted around and around. I'm not looking for numbers or dimensions. Just methods, like, here's how.... and no you can't or yes and here's where. It's sounding like I can't explain how to make a PBJ. And what the crap, Gene thinks I'm a woman! Solver got it, Michael and a couple others but man this just seemed to go south quick. Again I appreciate all the help and I'd be glad to suggest this to Chief if the demand is there, or anyone else can if you want. Personally I'm still very green with this software and it took me a little while to just find the section elevation I needed. Just please try to give more how to and where details and less criticism. 

I just don't understand your phrase "we always used pre-calculated heights for this heel height and the end height of the truss was always the same."  Because I have run this by my go-to guy at the truss plant and he thinks I am speaking Greek.

 

Explain this in detail and how it works for an 8-pitch roof with a 24 inch overhang, compared to a 6-pitch roof with a 30 inch overhang.

 

And I'm sorry, but someone named BnC, without a picture, cannot be identified as man or woman.  You might want to edit you signature a little, and include in it some details about your hardware setup.

 

It sounds like you want Chief to have a feature in the roof-build dialog that works like this:  If TRUSSES is selected, it would open up a one-of-two-choice checkboxes, and one path MUST be defined.

 

1.  Specify heel height (in which case the soffit top is not locked to wall plate height).

 

or

 

2.  Specify CANTILEVERED WITH PLATE-HEIGHT SOFFIT (in which case the heel height is a function of pitch, overhang, sheathing thickness, and fascia thickness.)

 

And if THAT is what you are after, go ahead and do a Suggestion in the Suggestion subforum.

[BnCKelley]

Ok, I've looked back at jobs where I used to work and here's what we did. We specified a height for the end heel of the cantilevered truss based on pitch. Overhang doesn't matter. If it was an 8/12 pitch it had a 6" heel. 12/12 was 6.25". You can also use calculated numbers at the wall for the truss but that's where overhang matters. All I wanted was to raise the roof enough to cantilever the bottom chord out to meet the truss. In playing with it more, if you don't go enough, it doesn't cut off the pointed tip on the bottom chord. The pitch and overhang can stay the same and the heel at the wall change, it's just a matter of plating the truss and your fascia size. We would do 16" overhangs at 14.5" long with specified end of truss heel heights for a 2x6. I could care less about getting that precise for what I'm doing I just needed to know the best way to raise it up enough. Again thanks for all the help and support. I got more questions but I'm about to afraid to ask, lol!

[Kbird1]

34 minutes ago, BnCKelley said:

 Again thanks for all the help and support. I got more questions but I'm about to afraid to ask, lol!

 

Don't be afraid to ask questions, nobody thinks you are stupid, people aren't like that around here, you just happened to ask about a Topic (Cant. Trusses) that has been a bug-bear around here for quite a few years, and as you can see quite a few Opinions etc . Being new around here means you just didn't realise you were opening a big can of Worms .

 

The Upside of course is Michael was kind enough to provide everyone the Macro's above to do a lot of the math without the Chief Cross Section Method being needed to figure it all out...  ( Thanks Michael ! )

 

Mick.

[BnCKelley]

Well here's stupid for you, I can't figure out how to do anything with it, lol! I clicked it and it was scrambled like eggs on a griddle. Somebody tell me what to do with that one please. And I'm trying to catch up with the abbreviations too. To avoid more post (just so it was less to read and a little embarrassing) I went as far as messaging one on one. It's a lot better for me that way, I don't have to read so much sometimes and I'm used to doing things more that way but it wasn't like by the other and I do understand. Thanks again guys, I'm really struggling but trying with asking to many questions. I'm 12 plans behind and this was supposed to speed me up.

[Kbird1]

3 hours ago, BnCKelley said:

Thanks again guys, I'm really struggling

 

Everybody did, you aint gonna get it all in a week ...or a month for that matter , chief is a pretty deep program......  and macros aren't on everyone's list to learn but Michael is one of the Forum's Macro Guru's and knows them inside out. 

 

Hopefully these pics help a bit :

 

 

 

[BnCKelley]

I think I have it downloaded. I also took a screenshot I will read through this tonight or tomorrow. Thanks

[Michael_Gia]

Below is a typical prefab truss order. 
Zoom into the bottom right image and you’ll see a cantilever truss system. 

I hope to one day see a checkbox for “cantilever truss” that should give me this condition automatically. 
You know, what we all thought “Trusses (no birdsmouth)” was supposed to do. 
And then maybe “raise off plate” should simply mean, I don’t know, raise off damn plate?... As in the distance between my top-plate and the bottom of my cantilevered chord? 
 

[ACADuser]

I too would like a check box for the cantilever truss.
This would disable "Automatic Birdsmouth" check box
It would place the bottom chord on the top plate.
The rooftop chord would be a function of the overhang, sub-fascia, and perhaps chord member heights.

I use Cantilevered trusses most of the time.

[Alaskan_Son]

13 hours ago, Michael_Gia said:

And then maybe “raise off plate” should simply mean, I don’t know, raise off damn plate?... As in the distance between my top-plate and the bottom of my cantilevered chord?

 

Which chord are you talking about?  Currently, Raise Off Plate is the distance between the top plate and the bottom of the top chord.  Or do you want this setting to generate a truss that is floating up above the wall?

[Michael_Gia]

3 hours ago, Alaskan_Son said:

Which chord are you talking about?

The bottom chord, Michael. 
 

You’re by far the brightest guy on this forum, I’m not sure why you’re struggling with this. 
 

There’s nothing to figure out or solve or develop macros for here. 
Chief just can’t do cantilever trusses, that’s all. 

If you zoom close into the bottom right image, you’ll see how the trusses sit on top of the wall and extend out past the exterior wall to create the eave/soffit. 

 

[GeneDavis]

Antics with semantics.

 

Chief doesn't really build the truss.  It just fits a trussy looking thing into whatever roof-over-ceiling envelope you, the Chief user, has created.  And then after you have "built" it, Chief offers you ways to edit it, i.e., end, drop gable, attic, etc.

 

It is up to you, the user, to create the proper envelope for a truss we're all calling a cantilevered truss, and doing that is straightforward and easy.

 

There are no tools or options in Chief to one-step that process of generating roof planes that are right for cantilevered trusses, and me, the guy who could care less about them, did the request in Suggestions, since the guys who are moaning about this did not, and came in here repeatedly to say stuff that, to some, made no sense.

 

You're welcome, Michael_.  And you too, BnC.  

[BnCKelley]

Thanks again y'all for all your help and the additional reading. Not sure why in the post I can't see your comment in parenthesis. It's initials, no pronunciation required. It's for BnC Farms originally. Nothing out there on it, that I'm aware of that's us, it's my wife and myself. We raised some horses and such, I built and raced Mopars for years and we just keep using BnC for things with more of a "business" or commercial use. I need more familiarity with the forum sites and such, I'm not even sure where or how to suggest anything at the moment. I had another post out there, not even sure what it was but didn't have any of the attention this one had. How can I see just me and my post topics?