Gable end truss supports
- Thread starter oachalon
- Start date
Zeke
Well-known member
Well, Bill's idea of sheathing the entire wall overlapping the hinge joint makes sense. It a perfect situation you would have 4' above and blow the joint and 4' wide x's how wide the wall is. Or variations of that theme. Not much wall below the hinge line at the door end. Just remember how much a full sheet resists flex over a 1/2 sheet (or less).
jack stand
Well-known member
You're going to need a drywall nailer on the inside of those Gables. Build a stiff back (a big fat "L") out of 2 2x8's as long as you can find. Then diagonally brace the vertical truss member in the peak to the neighboring truss all the way across making sure to attach the lateral bracing to this L. See what this does for you.
dfiler2
Well-known member
I have used 3/4 plywood In situations like that. Making sure that hinge was at the center of the sheet, glued and screwed it isn't going anywhere. I ran the sheets vertically, you do end up with some waste but the building hasn't moved any since 2011.
strutaeng
Well-known member
On the closed end gable adding a "girt," if you will, will take care of the problem. Think about a steel beam (I beam or wide flange) that is loaded vertically were it is the strongest:
If you turn the beam so the web is horizontal and place it at the hinge, then you can transfer the horizontal reaction of the hinge. The "support" is at the end walls where it can be transferred by your shearwalls. Doesn't "have" to be steel, maybe some 2x12s? Essentially you are just providing another support to studs at the hinge:
The other option I mentioned I thought about on a project we had. It was an architectural home with low-slope roof and lots of glass and a shade pocket parallel to the edge of the wall. We used welded channels at 4' on center to support the glass storefront laterally (cantilevered outriggers.) The trusses were top-chord bearing wood, and the other end of the channel framed back and were supported by framing between the top chords, similar to a header. Depending on horizontal wind direction, there was a upward or downward reaction transferred back there. We provided this force for the roof truss engineer to take into his design. A handful of tedious little connection details and wood lag screws checks, but worked well:
May not work exactly the same in your case, because your trusses are steep sloped and geometry is different, but that's the concept.
I hope this helps.
Since i have to build out the trusses to be flush with the interior wall for finishing and insulation would the following method work:
I essentially continue the lower studs but with 2x4s from the top plate all the way up securing the 2x4s to the truss and to the top plate, then with horizontal 2x4s i connect the adjacent scissor truss into each of those vertical 2x4s. Finally i sheath it making sure the sheathing does overlap that hinge?
Edit:
I essentially want to do what this guy did:
www.garagejournal.com
Thoughts? i can then also sheath it for more strength and spray foam?
I essentially continue the lower studs but with 2x4s from the top plate all the way up securing the 2x4s to the truss and to the top plate, then with horizontal 2x4s i connect the adjacent scissor truss into each of those vertical 2x4s. Finally i sheath it making sure the sheathing does overlap that hinge?
Edit:
I essentially want to do what this guy did:
Tying trusses together
Guys, I'm try to get a wall in my garage ready for sheet rock. I have a 10ft wall with scissors trusses. The gable end is above the 10ft area of the wall. When my builders built the wall I noticed the gable sits flush with the outside, but not inside. I ended up adding some 2x4's and plywood to...
www.garagejournal.com
Thoughts? i can then also sheath it for more strength and spray foam?
Last edited:
On the closed end gable adding a "girt," if you will, will take care of the problem. Think about a steel beam (I beam or wide flange) that is loaded vertically were it is the strongest:
If you turn the beam so the web is horizontal and place it at the hinge, then you can transfer the horizontal reaction of the hinge. The "support" is at the end walls where it can be transferred by your shearwalls. Doesn't "have" to be steel, maybe some 2x12s? Essentially you are just providing another support to studs at the hinge:
The other option I mentioned I thought about on a project we had. It was an architectural home with low-slope roof and lots of glass and a shade pocket parallel to the edge of the wall. We used welded channels at 4' on center to support the glass storefront laterally (cantilevered outriggers.) The trusses were top-chord bearing wood, and the other end of the channel framed back and were supported by framing between the top chords, similar to a header. Depending on horizontal wind direction, there was a upward or downward reaction transferred back there. We provided this force for the roof truss engineer to take into his design. A handful of tedious little connection details and wood lag screws checks, but worked well:
May not work exactly the same in your case, because your trusses are steep sloped and geometry is different, but that's the concept.
I hope this helps.
Thank you for the drawings. My question would be with your first picture how could I do that with the garage door side? I don’t think the doors would clear that additional support? Maybe I’m wrong?
billconner
Well-known member
Following up on the sheathing, like Zeke said, center ply vertically over hinge line. I like the idea of 3/4. You can get nearly the full strength in a splice of same ply overlapping 1' with glue. That's from APA stressed skin design. You could beef up exterior sheathing by adding splice plates to that.
A lot of work, but if you want interior sheathed anyway, maybe not so much extra over some sort of beam/post etc. trying to stiffen it, and less obtrusive.
A lot of work, but if you want interior sheathed anyway, maybe not so much extra over some sort of beam/post etc. trying to stiffen it, and less obtrusive.
strutaeng
Well-known member
Yeah, I wasn't sure how that would work on the garage door side. How far up do the garage doors go? Are they roll-up doors or overhead?
What's this dimension?
Are you going to have a ceiling?
I have to measure but that is a 2x12 header. I’m guessing a little over 2ft. Yes I will have full ceiling and walls. Why I’m trying to get rid of bracing because it’s in the living space and also the look.Yeah, I wasn't sure how that would work on the garage door side. How far up do the garage doors go? Are they roll-up doors or overhead?
What's this dimension?
Are you going to have a ceiling?
Here’s an article from Mitek on this exact issue.. standard gable end trusses specify your exact bracing situation and this was a miss on whoever ordered/framed your building.
mike93lx
ALLIANCE MEMBER
Easy, 2x8.
mike93lx
ALLIANCE MEMBER
Oh I know, just saying it was a hurdle that could have been jumped.
The suggestions of adding overlapping bracing are interesting. I still think getting an engineer is best, but acknowledge that is expensive and won't be simple.
Could just add new bracing until the wall doesn't move around at all.
billconner
Well-known member
You can go 20' with 2x6, 24' on center, in non-load bearing, per IRC.
The walls don’t move around at all right now. Building is very sturdy and very tight. It’s just when I go to finish I don’t want to see those 2x4s sticking out my finished walls.
I think adding overlapping bracing as well as 3/4 sheathing over the hinge might work great. I was thinking about adding that metal paneling on the front and back wall as a finish. Maybe sheath the entire 2 walls and then put that over top.
mike93lx
ALLIANCE MEMBER
If you take those out, i bet it will move around. That's what I meant
mike93lx
ALLIANCE MEMBER
I'm confused. Building out the trusses?
The trusses are 2x4 and the top plate is 2x6, so there is a gap between the truss and the end of the wall on the interior. I need to build it out so i can insulate there as well as have a place to attach the 3/4" plywood to. Thats what i mean by build out. Sorry i was pretty general in my statement.
mike93lx
ALLIANCE MEMBER
Ah, the gable truss. I thought you were going to build out the scissor truss to meet the gable wall.
You could maintain the bracing current scheme by making the ceiling a hip design. The end bracing is done all in one plane and then ceiling applied. You lose a little space at each end doing this, but it will look nice and be strong.
The other move is to go to the middle support for the door openings and cut the board above the short stud wall above the openings and run full height one piece 2 X 12s sistered on to the inside of the door "king studs". Add in appropriate horizontal members to fill the space between the "on flat" studs in the end gable and your new full length king studs that run all the way up.
Where the new king studs bridge the two stud walls, make it a "hog trough" configuration - in between the two kings is another piece of 2x whatever to fit, nailed up solid in between the kings.
At the other end do the same but box it in - when you finish and call it a post.
The other move is to go to the middle support for the door openings and cut the board above the short stud wall above the openings and run full height one piece 2 X 12s sistered on to the inside of the door "king studs". Add in appropriate horizontal members to fill the space between the "on flat" studs in the end gable and your new full length king studs that run all the way up.
Where the new king studs bridge the two stud walls, make it a "hog trough" configuration - in between the two kings is another piece of 2x whatever to fit, nailed up solid in between the kings.
At the other end do the same but box it in - when you finish and call it a post.
Regardless of what you do it seems like you’d end up with a hinge point.
The correct way to do gable ends with scissor trusses is either get a scissor gable and balloon frame to the bottom of it, such that all bracing is in the plane of the ceiling or above, or balloon frame the entire wall.
I understand neither of those are possible at this point, but there will be play in that wall if you remove the brace. You can probably physically push a least a half inch of deflection at the middle of the wall without that brace.
As many people here have already said, you should consult an engineer. A couple photos and your truss sheets and they should be able to provide a solution at a very decent price point
The correct way to do gable ends with scissor trusses is either get a scissor gable and balloon frame to the bottom of it, such that all bracing is in the plane of the ceiling or above, or balloon frame the entire wall.
I understand neither of those are possible at this point, but there will be play in that wall if you remove the brace. You can probably physically push a least a half inch of deflection at the middle of the wall without that brace.
As many people here have already said, you should consult an engineer. A couple photos and your truss sheets and they should be able to provide a solution at a very decent price point
Why is there a 2x12 header on a non load bearing wall?
Interesting. Wonder why? Not that it's a bad thing I suppose, but "overkill" wastes materials and $$ too.
nmk_61802
Well-known member
This is the proper solution, and then the bracing can be addressed:
www.garagejournal.com
Shop wall bowing out
we need an end to this ordeal. Pole barn. I know, not helpful, but this is an engineering area where pole barns shine.
www.garagejournal.com
sjvicker
Well-known member
It's not correct but if I was in your position, here's what I would do.
1. Build a 2x4 "truss" with a bottom cord that can sit on your wall header and has studs that line up with your wall framing. Build this on the ground and hoist it into place so your studs aren't toe nailed. Create a solid connection to your gable truss and header with structural screws.
2. through bolt the connection between your self-built truss and the wall. 2 bolts between studs and at least 1/2" diameter with large washers.
3. Sheet wall with 3/4" plywood, ensuring that you put 4' on the truss and 4' on the header to split the joint.
If you aren't going to finish the inside then I'd do #1 and run 1.5"x1.5" angle iron on each stud from floor to roof with a structural screw at least every foot.
1. Build a 2x4 "truss" with a bottom cord that can sit on your wall header and has studs that line up with your wall framing. Build this on the ground and hoist it into place so your studs aren't toe nailed. Create a solid connection to your gable truss and header with structural screws.
2. through bolt the connection between your self-built truss and the wall. 2 bolts between studs and at least 1/2" diameter with large washers.
3. Sheet wall with 3/4" plywood, ensuring that you put 4' on the truss and 4' on the header to split the joint.
If you aren't going to finish the inside then I'd do #1 and run 1.5"x1.5" angle iron on each stud from floor to roof with a structural screw at least every foot.
billconner
Well-known member
Horizontal beams at the hinge point tied in to o side walls should also correct this. My instinct is at least 2' deep (in plan) if wood and ply, but someone could convince me less might work, and steel is an option. Use it for storage or display maybe?
WNYflyer
Well-known member
As part of the contractor's work he should have installed runs of horizontal bottom chord bracing/bridging on top of the bottom chords of the scissor trusses in accordance with your truss tech sheets...............in other words at a max spacing of 8'-3 11/16". This bracing/bridging is only as good as what it is anchored to and a wall with a hinge or non properly braced gable truss are not proper anchorage structures. Go into any Home Depot, Walmart type building you will see essentially the same type of bracing/bridging on top of the bottom chords of the steel joist/trusses and the bracing/bridging is anchored at their ends into a solid stable structure such as a CMU wall, tilt-up concrete panels, etc.
According to your tech sheet for the gable trusses the trusses are not design for wind perpendicular to them which seems strange given the whole intent is for those trusses to paced at the end/gable and thus subjected to that perpendicular wind. Anyhow because of that lack of design for that wind direction they are saying the gable trusses need to be braced in accordance with the tech sheet. I believe someone has already posted a directive/tech sheet on ways to accomplish that.
Between the required truss bracing, minimal structure at the gable end with the OH doors (i.e. amount of shear wall left? size of door jamb material which is essentially supposed to replace the strength of the wall studs eliminated by the doors) and most importantly the hinge joint problem you would be well served to consult a professional to sort out a fix that jives with your vision of the finished product. Unfortunately that will cost some $ and that is assuming you can find someone to tackle the job. That said good luck, looks like it will be a nice space when finished.
According to your tech sheet for the gable trusses the trusses are not design for wind perpendicular to them which seems strange given the whole intent is for those trusses to paced at the end/gable and thus subjected to that perpendicular wind. Anyhow because of that lack of design for that wind direction they are saying the gable trusses need to be braced in accordance with the tech sheet. I believe someone has already posted a directive/tech sheet on ways to accomplish that.
Between the required truss bracing, minimal structure at the gable end with the OH doors (i.e. amount of shear wall left? size of door jamb material which is essentially supposed to replace the strength of the wall studs eliminated by the doors) and most importantly the hinge joint problem you would be well served to consult a professional to sort out a fix that jives with your vision of the finished product. Unfortunately that will cost some $ and that is assuming you can find someone to tackle the job. That said good luck, looks like it will be a nice space when finished.
Just wanted to give an update. The builder is going to cut portions of the top plates out and run full 2x6 studs next to the current studs from the bottom plate all the way up to the top of the trusses. I might still sheath the walls when it comes time to finishing as well as still adding additional bracing that goes from the scissor truss to the gable trusses
As part of the contractor's work he should have installed runs of horizontal bottom chord bracing/bridging on top of the bottom chords of the scissor trusses in accordance with your truss tech sheets...............in other words at a max spacing of 8'-3 11/16". This bracing/bridging is only as good as what it is anchored to and a wall with a hinge or non properly braced gable truss are not proper anchorage structures. Go into any Home Depot, Walmart type building you will see essentially the same type of bracing/bridging on top of the bottom chords of the steel joist/trusses and the bracing/bridging is anchored at their ends into a solid stable structure such as a CMU wall, tilt-up concrete panels, etc.
According to your tech sheet for the gable trusses the trusses are not design for wind perpendicular to them which seems strange given the whole intent is for those trusses to paced at the end/gable and thus subjected to that perpendicular wind. Anyhow because of that lack of design for that wind direction they are saying the gable trusses need to be braced in accordance with the tech sheet. I believe someone has already posted a directive/tech sheet on ways to accomplish that.
Between the required truss bracing, minimal structure at the gable end with the OH doors (i.e. amount of shear wall left? size of door jamb material which is essentially supposed to replace the strength of the wall studs eliminated by the doors) and most importantly the hinge joint problem you would be well served to consult a professional to sort out a fix that jives with your vision of the finished product. Unfortunately that will cost some $ and that is assuming you can find someone to tackle the job. That said good luck, looks like it will be a nice space when finished.
Flat bottomed gable trusses are designed to be used with flat ceiling “standard” trusses, where the ceiling drywall and roof sheathing brace the roof assembly. When you mix and match scissor trusses with flat bottomed gable ends, you end up with issues…