Dropped Gable Truss Vs Stick Framing Gables for Truss Project

[E M]

Have a project with some wide gables (62/0 & 57/0). It's a commercial project.
Normally I would just draw a dropped gable truss and call it done. At least in a situation where there are no attic spaces that require insulating and/or have windows in them.

But as I think through a smaller gable that has a large window it has me thinking about stick framing that gable.
And that got me thinking that because of these wide gables it might make sense just to do the same detail for all the gables while we're at.

Part of the concern is for some of the areas there MAY be brick at the gables although we are leaning away from that at the moment so kind of trying to hedge my bets and at least think it through for both scenarios.
Would seem to me that having the perpendicular stud backup for the masonry would be much more structurally viable solution for a lot of reasons.

So that got me thinking about why can't the truss fabricator make up gable end wall trusses with the web members (and top and bottom chords?) framed perpendicular to the normal way of doing things? Similar to floor trusses.

Anyone have any experience with gable trusses framed in this manner?

As far as the window gables would be concerned I can see how this could potentially be a coordination nightmare.... but maybe not.

So how do you normally start thinking through some of these concerns
Stick frame all gables?
Stick frame all gables with windows in them?
Stick frame all gables that will have either Brick or stone veneer?
Stick frame all gables of x width?
Stick frame all gables that will be insulated with Batt? What about spray foam?

 

[RontheRedneck]

"...why can't the truss fabricator make up gable end wall trusses with the web members (and top and bottom chords?) framed perpendicular to the normal way of doing things?"

We call them "wall gables". It sounds easy in theory. In practice - Not so much.

Our production tables have rollers on them that are 1.5" above the table. They're rolled over the trusses to press the plates in. Then the trusses exit the building by going through a double roller that makes sure all the plates are seated. So there's no way to build a gable on the tables that's 3.5" or 5.5" thick.

So the only way we can do it is to lay a common truss on the ground and have the guys assemble a wall gable on top of it by hand. Not an easy thing to do.

Then handling them is difficult. They're not plated together like a regular gable. They have to be picked up and stored. Then picked up and loaded on a truck. The unloaded at the jobsite and set on the walls with a crane. They don't tend to hold their shape well.


So while building them is possible, we try our best to avoid it.

 

[E M]

Ron-
Thanks for that explanation!
Makes perfect sense now.
As far as percentages go would you say you do more truss packages with or without gable trusses (talking the normal type or dropped not the kind the post was about with web members perpendicular.... beause thinking now that would be an anomoly.

 

[RontheRedneck]

"As far as percentages go would you say you do more truss packages with or without gable trusses..."

A wild guess would be that 95% of our jobs have gables of some kind. The "wall gables" - Maybe one or two a year.

 

[E M]

Interesting again. Would have guessed (for no particular reason) that it would have been about 50/50 with and without gable trusses.
So then. Along those lines would you see any real benefit to stick framing the gable trusses?
For large gables?
For gables with say brick veneer?

 

[JAE]

E M,
The concept of this site is that of Engineers helping Engineers.

I appreciate your posts and the questions. Always interesting of course.
But site policies strongly urge participants to also help others. Part of the bargain here.

In looking at your profile, all 29 of your replies since you've joined Eng-Tips have been in your own posted questions.

Please feel free to help others. Thanks.

Site Policies:

https://www.eng-tips.com/market.cfm

 

[E M]

JAE-
I'm happy to help when I can.
I'll see what I can do.

 

[waross]

Framing is not my area, but years ago I was called in to set up a framing machine in a "Pre-Built Home" factory.
While the new machine that I worked on just did straight framed walls, they had the original manual framing tables that would have easily accommodated "wall gables".
This type of plant is probably the type that see most of the "wall gables".

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[E M]

Thanks Waross for your insight…. From a different perspective. Not electrical engineer but was electrician in the navy. Always interesting to me how electrical types get to see a lot of different sides to the equations

 

[RontheRedneck]

The OP asked: "Along those lines would you see any real benefit to stick framing the gable trusses?"

The only situation that comes to mind is an end wall where there are scissor trusses. I'd prefer to see a balloon framed gable wall from the subfloor up to the underside of the roof.

 

[E M]

Ron-
Actually have that situation this project on one of the gables. Let me think on what you are suggesting and see if I can come up with why this situation might require a different consideration. Thanks!

 

[lexpatrie]

Can I get a drawing or sketch of what's being described here?

And I'm going to state my philosophical objection to calling this "balloon framed" when it's hand framed, or stick framed. Balloon frame has a two story stud with a floor joist nailed to it mid-height. That term is being misused by a lot of people here.

 

[misterengineer]

JAE - Concerning your message to E M: I feel very strongly that there is value added to the website even when they only ask questions but never reply to posts by other engineers. By posting a question you are helping others who may have the same question now or in the future, so you undeniably helped other members indirectly. If it makes anyone angry that someone never responds to posts, they can easily ignore the post, but they may be passing up an opportunity to learn something. Just my thoughts.

 

[gte447f]

says the guy who created a new account just to add 1 meaningless, off-topic reply to a thread

 

[lexpatrie]

I don't check people's participation quota or whatever you call it. There's a group of maybe eight to ten folks who are steady contributors, I won't hold myself out as on of them, but I get a nice glowy feeling helping. Even if it's just a "me" feeling, and I'm actually of no use to anybody here. Most of the questions prompt me to dig in a little and see what "material" is out there, sometimes something useful turns up. It's funny how often that happens. I've got nobody to mentor in-house, ... sometimes the questions can be exasperating, some are more eyeroll, and then there are the little tangles with other members misconstruing or misunderstanding what you meant. It's a net positive. Perhaps, to quote John Bender, "That's social... Demented and sad... but social."

 

[JAE]

Sheesh. I thought I was very polite.

 

[Jdub Engineer]

I'm in a high wind region, and often the ceiling is not strong enough to brace the gable wall. In those conditions, we balloon frame the wall from floor to bottom of lookout or bottom of roof sheathing and we design these studs to be full height (sometimes need extra studs or lvl's). When the ceiling is strong enough to be a brace, and it will be connected to the wall well enough, then I'd say it's standard practice to put a gable truss on top of the wall. it makes the framing much simpler and is pretty easy for truss manuf's to provide. The truss manuf typically sends a diagram that specifies how to brace the gable truss when it gets taller than 6' (this is done instead of supplying "wall gables").

I think this connection from ceiling to the gable wall is a common failure point in wood structures in high wind regions, so newer codes are trying to address this by adding better connections from ceiling to the wall (strapping the wall to the ceiling, adding blocking in the ceiling, adding plywood in the ceiling). but these connections are kinda painful to install so I just will ignore the ceiling for many conditions.

JW

 

[XR250]

You could use (2) gable trusses and nail them together to act compositely to maybe get the stiffness you need.
I generally call out that the gable webs be "T" braced by adding a vertical 2x4 to each one with the strong axis perp.