reason for not spanning wood truss over 40'

[Shovelhead]

Why is this even a question? Indoor riding arenas use wood trusses up to 90ft wide.

Why did you even reply if you can't answer the question. I ain't building no stinkin ridin arena. I know wider trusses can be built.
Is everbody in Northern VA a d'k head or just you?

You're starting to sound like the kind of customer that should be fired.
Could you make it more tedious and contentious? You seem to not be communicating effectively with them. It isn't a damned hot potato / tennis match, it's an RFQ.
Just tell them exactly what you want / need and get their answer / cost.

WTH you babbling about???
I did ask them and did get an answer.
Wanted to hear from folks who have had a similar experience with my particular questions.
Insert yer location with the fella above.

 

[Shovelhead]

Many good reasons have already been mentioned. I'd speculate that the gang plates used to hold the trusses together may be a limiting factor. They may need to use larger plates than 2x4 or 2x6 can handle. If the plate is 7" wide they may need to build the truss, or parts of it, out of 2x8 and this could drive the costs up. And their truss building tables may be set up for a 'standard' of 2x4/2x6 lumber and they may need to reset things.

Another reason for the cost difference is that it could be the 40' truss is already in their system as a designed item. Maybe they don't already have a 44' truss and need to design/engineer this length.

Here's a video that shows an older truss table system:

And here's the newer automated pin type:

Thank you sir. Just the kind of answer and info I was trying to get.
I surely appreciate it.

 

[sberry]

I agree that 44 may be off speed.

 

[Shovelhead]

I agree that 44 may be off speed.

I won't disagree with that.
I'm going to make 40 work or go back to red iron.
Started at 40x60 but width get's me more usable floor space for my needs.

Can't go much wider than 44 due to future house and road/drive location.

Back to my graph paper.

Thanks

 

[ClappedOutBport]

Many good reasons have already been mentioned. I'd speculate that the gang plates used to hold the trusses together may be a limiting factor. They may need to use larger plates than 2x4 or 2x6 can handle. If the plate is 7" wide they may need to build the truss, or parts of it, out of 2x8 and this could drive the costs up. And their truss building tables may be set up for a 'standard' of 2x4/2x6 lumber and they may need to reset things.

Another reason for the cost difference is that it could be the 40' truss is already in their system as a designed item. Maybe they don't already have a 44' truss and need to design/engineer this length.

Here's a video that shows an older truss table system:

And here's the newer automated pin type:

That second video is shot in my hometown. Should make getting trusses easily if I ever build a big building.

 

[karoc]

Shovelhead what I did which I had no ideal what kind questions to ask nor do I know anything about trusses. It was recommended to me to call one of the local truss companys to explain what I was building. So I called and the nice lady ask ask all kinds of questions about overhang etc,if I was going to deck it or just metal roof. By the end of the day she sent me three diagrams with specs on them and a diagram of the trusses what they look like with a 4/12 pitch. I was only suggesting cause this is what I did plus asking here like you. Not being like smarta$$$

 

[sberry]

I won't disagree with that.
I'm going to make 40 work or go back to red iron.
Started at 40x60 but width get's me more usable floor space for my needs.

Can't go much wider than 44 due to future house and road/drive location.

Back to my graph paper.

Thanks

It may be worth a little pain to go to 44. Every foot here makes for a wayyyy bigger feel and makes all the running space along the walls usable. There is sugh a huge leap from 30 to 40 wide and 44 vs 40 would be noticeable to experienced men that have worked in both sized buildings.
Graph paper has its uses but you cant feel it and its often used for measuring things which is useful but garages are really about people and movement. Wider gives so much to turning, walking, rigging, some storage and tools.
Iron is often in widths of 10 ft and wood would likely be easier to go off a bit.

 

[Bobthetractor]

The spans get funny. I've got 36' clear span with 2' overhang on each side. If you want 48' and put a load bearing post in the middle, it shouldn't be a problem. I wanted 48' open and settled on 36'.

Talk to another truss manufacturer if you want. Remember the manufacturer is getting them made to the specs of the engineer (liability). On the commercial side I run into various engineers that overengineer things because they are maybe old and set in their ways but also its less chance that they get sued. That said, you're in 140mph or more hurricane zone so you've got more uplift design constraints than downforce. For my building (which was ag) I spoke to a friend of a friend who was an engineer for a second opinion to my truss designer and while he gave me specs I couldn't remember he strongly encouraged me to not go a wider span due to uplift and racking concerns. Btw, if you're building a nonresidential structure you can probably widen out the truss spacing. I went 12' OC with two ply trusses (basically two of your "standard" 2x6 trusses nailed together with 2x6 purlins on edge. You can't do this with snow loads but you can get the same uplift and cut your truss requirements which usually is the most costly piece of structure to manufacturer and install.

If you have truss plans I'm happy to give a non-engineer review.

 

[Shovelhead]

Shovelhead what I did which I had no ideal what kind questions to ask nor do I know anything about trusses. It was recommended to me to call one of the local truss companys to explain what I was building. So I called and the nice lady ask ask all kinds of questions about overhang etc,if I was going to deck it or just metal roof. By the end of the day she sent me three diagrams with specs on them and a diagram of the trusses what they look like with a 4/12 pitch. I was only suggesting cause this is what I did plus asking here like you. Not being like smarta$$$

Thanks. Good info.

It may be worth a little pain to go to 44. Every foot here makes for a wayyyy bigger feel and makes all the running space along the walls usable. There is sugh a huge leap from 30 to 40 wide and 44 vs 40 would be noticeable to experienced men that have worked in both sized buildings.
Graph paper has its uses but you cant feel it and its often used for measuring things which is useful but garages are really about people and movement. Wider gives so much to turning, walking, rigging, some storage and tools.
Iron is often in widths of 10 ft and wood would likely be easier to go off a bit.

True. You don't know how much time I've spent in my 30x50 with a tape measure and looking at different options for all my tolls, benches, shelving, cabinets, and other ****.

You'd think a feller that's had this size shop since 96 would know EXACTLY what he wants in the next one. And I do, but my *** pocket won't allow for the EXACTLY part, so I'm figgerin it all to ever last inch.

The spans get funny. I've got 36' clear span with 2' overhang on each side. If you want 48' and put a load bearing post in the middle, it shouldn't be a problem. I wanted 48' open and settled on 36'.

Talk to another truss manufacturer if you want. Remember the manufacturer is getting them made to the specs of the engineer (liability). On the commercial side I run into various engineers that overengineer things because they are maybe old and set in their ways but also its less chance that they get sued. That said, you're in 140mph or more hurricane zone so you've got more uplift design constraints than downforce. For my building (which was ag) I spoke to a friend of a friend who was an engineer for a second opinion to my truss designer and while he gave me specs I couldn't remember he strongly encouraged me to not go a wider span due to uplift and racking concerns. Btw, if you're building a nonresidential structure you can probably widen out the truss spacing. I went 12' OC with two ply trusses (basically two of your "standard" 2x6 trusses nailed together with 2x6 purlins on edge. You can't do this with snow loads but you can get the same uplift and cut your truss requirements which usually is the most costly piece of structure to manufacturer and install.

If you have truss plans I'm happy to give a non-engineer review.

Appreciate it.

 

[383]

We set these 70' clear span trusses 4' oc on an airplane hanger this spring, price was around $500 each.

Trusses over 10'6" wide require oversize load permits, maximum is 14'.

 

[dcg9381]

There is a point where the height of the truss makes it difficult to transport, you end up with a two piece truss, the top is a separate piece. I dunno if 40 foot is that point as it depends on the roof pitch.

Yep, ran into this. We could order it, but finding someone with a trailer long enough to carry one was a problem. Typical 1-ton transportation trucks with a 30' trailer - it's enough overhang that they get stopped while transporting. Next step up is a semi and it's $$.

 

[mkarlin]

The folks I'm working with to get quotes on a shop are telling me they prefer not to span over 40' with wood trusses on a stick built building.

I remember reading somewhere that the cost may jump substantially once you go over 40'.
Is that correct?
Is there any other reason why?

Shop would be 48-50' in length.

~44w x 48d

Thanks

We are currently building (basically- has a cut back for asthetics) a 50 x 140, and my contractor told he 50 is the cut off for free span. Once over 50 they get alot more expensive.

 

[sberry]

Once over 50 they get alot more expensive.

Duh,,, they cover more.

 

[chris142]

There is a point where the height of the truss makes it difficult to transport

Sent from my SM-G965U using Tapatalk

I delivered them in the past. The trailer I pulled was expandable out to 65ft from kingpin to front axle. We had some huge trusses on it. One set hung out the back 18ft and 5ft on each side.

 

[LifeLongWNYer]

I just visited a small, family run, truss plant in the Finger Lakes. VERY interesting.

They have a maximum of 60' span and a 13' height from the bottom chord to the roof peak, for a one piece truss. That is because that is as large as they can move on the highway.

The software that they use to design the trusses was very cool. They enter the overall span and the desired height, then let the software figure where to put in the braces. If they need to move a brace, or change something else, the software calculates the safety of the new design, and changes the color of any pieces that are unsafe to a different color. They can move things around, add more webs, or change the size of a 2x? to something different, until the software "likes" the design and makes all the members green.

It was a fascinating afternoon.



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