# Building trusses



## smeagol (May 13, 2008)

I need to build 5 trusses 40' for our equipment shed. I am doing this in order to save 900$. I would use resorcinal in the summer, PL premium in the spring/fall. Any advice on a 10 F degree advice would be appreciated. Thanks


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## J L (Nov 16, 2009)

Sorry, I can be dense. What is the question?


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## Kent Whitten (Mar 24, 2006)

Oh boy, please don't go down this road. Get the truss company to build them.


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## KennMacMoragh (Sep 16, 2008)

I remember being told people used to build their own trusses all the time, they would use plywood gussets glued and nailed. But now a days they have to be engineered if you're going to build them on site. The cost of engineering and labor would be more than that $900 you are saving.


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## PCI (Jun 8, 2012)

I understand that you are probably not including your own labor into this price, but I can't build simple 12' trusses installed for the price of engineered ones installed. 

I know there are a lot of you that are more skilled and faster than I am, but I can't make the numbers work.


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## RobertCDF (Aug 18, 2005)

I'd find a new truss company... that would cost me under $500 from a couple of places.


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## CJ21 (Aug 11, 2007)

I can build trusses but it for a shed or a garage. House trusses I usually left to the pro's.


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## jkfox624 (Jun 20, 2009)

Our codes are pretty lax around here and its a big no no to build your own trusses.


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## Rustbucket (May 22, 2009)

There is a lot of math and engineering that goes into truss design. You can't just build a triangle and put in some webbing to make it "look right." It's all about the properties of the materials and load paths. Besides, you would never get away with it on a permitted job.


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## smeagol (May 13, 2008)

Where i live there is no permit required for an ag building. The trusses will be 4/12s 9' o.c. 13" heel I know i am overkilling it with 2x12 rafters and bottom chords, but for 26$ for a 22' #2and better fir it's common sense.


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## Kent Whitten (Mar 24, 2006)

Especially a low pitch roof. Don't do this. You are just asking for a structural failure.


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## knucklehead (Mar 2, 2009)

Let me think about this for a day or two.


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## jkfox624 (Jun 20, 2009)

Anything small say 20 feet or so i could say go for it. A 40' span has alot of engineering in it. Even when the calcs are done for them ive seen catastrophic failure. About 10 years ago one of the bays at the lumberyard collapsed. Hard winter with a deep snow pack on the roof, then a quick warmup with 2 inches of rain. It happened during business hours, thankfully no one was inside. Spend the extra money and rest a little bit easier that someone doesn't die because you wanted to save some coin.


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## cleveman (Dec 28, 2007)

Trusses I have made in the past were for 24' spans. I just copied the storebought trusses, but I used full 2x4 material, and douglas fir at that.

I would recommend buying one and taking your measurements off it, or finding one in a building already constructed and copying it.

If you have a building to build them in, this will take care of the glue problem, with a bit of heat, no? I guess you need a 40' plus building with an overhead door on the end.

How will you lift these monsters?

Can't you contact an adhesive company and find an adhesive, so you can build them on site?


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## ohiohomedoctor (Dec 26, 2010)

10' by 40' is an odd size for a building. .


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## CITY DECKS INC (Sep 4, 2012)

smeagol said:


> I need to build 5 trusses 40' for our equipment shed. I am doing this in order to save 900$. I would use resorcinal in the summer, PL premium in the spring/fall. Any advice on a 10 F degree advice would be appreciated. Thanks


get them made...prefab....order. there cheap..


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## ohiohomedoctor (Dec 26, 2010)

Balsa wood and tin foil gussets..


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## Kent Whitten (Mar 24, 2006)

ohiohomedoctor said:


> 10' by 40' is an odd size for a building. .





smeagol said:


> ...9' o.c. ....


I am going to guess it will be around 36x40 from this statement. If this is the case, I would say that you are just plumb ass crazy to even think of "making a truss"


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## ohiohomedoctor (Dec 26, 2010)

And 9' oc? Good God brotha. Get ahold of yourself.. :laughing:

Ill bet when you factor everything up, even if you do not value your own time, it will be cheaper to have them made and delivered.


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## overanalyze (Dec 28, 2010)

Been watching this thread...and to the op..note that no one thinks your so called savings will be worth the risk. Please respond to us that you had a "duh" moment and you really are going to purchase these trusses...please....


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## cleveman (Dec 28, 2007)

I say it is a great idea. You just need a proper design.

I seem to think it was Lombard, IL where they were building a large exhibition hall with wood trusses and the entire structure collapsed during construction.

The engineering firm wanted to prove that it was no fault of the design, so they rebuilt it immediately and braced the trusses properly the second time.

Just find someone with a 40' span and go and take some measurements.


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## cleveman (Dec 28, 2007)

http://desmoines.craigslist.org/mat/3471113511.html

Don't these look real light for 9' spans?


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## Stunt Carpenter (Dec 31, 2011)

cleveman said:


> http://desmoines.craigslist.org/mat/3471113511.html
> 
> Don't these look real light for 9' spans?


They look like they are girder truss of some sort not having any tails. 

Strange to see someone selling a few truss like that


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## skcolo (May 16, 2009)

You should build your own crane to hoist them up also.


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## kiteman (Apr 18, 2012)

AirdrieHandyman said:


> They look like they are girder truss of some sort not having any tails.
> 
> Strange to see someone selling a few truss like that


They look like fairly typical pole barn trusses to me. Barn probably got shortened after they ordered everything.


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## hdavis (Feb 14, 2012)

Interesting thread so far. Making a 40' truss is just like making a 20' truss. You'd think you could just double the width of the lumber and make the same design scaled up. Double the load, so double the width to keep the stresses constant. One issue is the weakest point in a 22' length of #2 is likely weaker than the weakest point of an 11 footer. This can be worked around by cherry picking or upsizing. The real gotcha is without the engineering calculations, you don't know which members are prone to bending failure. Avoiding bending failure requires a greater thickness (you'd have to double the thickness to get the same bending performance in a 2X scaled design) or solid blocking or stiffeners... I don't have an inherent problem with site built 40' trusses - there were standard designs for timber based ones that went to 60' and beyond.

I'm not sure where glue comes into the picture - for any of the site built designs I've seen, glue gets no structural rating at all - only conventional fasteners have rated capacities. That isn't to say I don't use it for added insurance:whistling


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## Rio (Oct 13, 2009)

We've done field built trusses but those were for a church that wanted the big heavy duty truss look, were engineered of course, and the engineer also inspected the lumber that was used to fabricate the trusses. 

At the least you need an engineered design and as pointed out for the $900.00 you're going to save the design will probably cost that much


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## hdavis (Feb 14, 2012)

skcolo said:


> You should build your own crane to hoist them up also.


Gin pole


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## skcolo (May 16, 2009)

hdavis said:


> Gin pole


Where's the fun in that?


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## hdavis (Feb 14, 2012)

skcolo said:


> Where's the fun in that?


I never heard of a crane dancer...


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## CanningCustom (Nov 4, 2007)

This is just plain and simple a bad idea. Totally homeowner kind of idea. Even if you own software like MiTek and know how to use it. The con's out weight the pro's. Like what kind of glue would be best, what size plywood gussets and where would they go. How about what kind of nailing pattern would be good enough without destroying the integrity of the wood sandwiched betwen the plywood gussets. These are just examples, with out all of these answers for starters the structure will fail.


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## hdavis (Feb 14, 2012)

Nailing patterns and glue choice? Nailing patterns are published. Glue isn't even needed, he could use chewing gum.


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## Kent Whitten (Mar 24, 2006)

That would be an obvious assumption to those that are educated and trained in structure and truss building. I'm pretty confident that the op is far from that. 

It is also our duty as professionals to discourage this type of practice since the world is reading everything we say.


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## olligator (Nov 23, 2007)

40' is a decent span. Use big stock and make scissor trusses. You'll get the cathedral/vaulted look for free. :whistling


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## ohiohomedoctor (Dec 26, 2010)

You can do it.... (Read is Rob Synder voice)

But you shouldn't. .. (Read is Darth Vader voice) shhhhhh


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## Rob1954 (Jun 22, 2010)

RobertCDF said:


> I'd find a new truss company... that would cost me under $500 from a couple of places.


$100 per truss for trusses designed to span 40ft at 9ft on centers?
Delivered? Five trusses? Those would be 2x6 top chord / 2x8 bottom chord where I'm at and would probably be $250 each in such a small quantity.

Building your own trusses is maybe ok if its a short span and you have _*nothing*_ else to do. Building 40ft span trusses with such a large tributary spacing......bad idea.


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## hdavis (Feb 14, 2012)

Kent Whitten said:


> That would be an obvious assumption to those that are educated and trained in structure and truss building. I'm pretty confident that the op is far from that.
> 
> It is also our duty as professionals to discourage this type of practice since the world is reading everything we say.


Points taken.

Down in Texas you used to be able to go to the Ag extension and get working plans for site built trussed agricultural buildings. Maybe they still encourage people to build their own ag buildings.


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## ohiohomedoctor (Dec 26, 2010)

Rob1954 said:


> Building 40ft span trusses with such a large tributary spacing is definately a bad idea.


Fixed it.


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## CanningCustom (Nov 4, 2007)

hdavis said:


> Nailing patterns and glue choice? Nailing patterns are published. Glue isn't even needed, he could use chewing gum.


Nailing patterns are published ? For making home made trusses? Really well then their is no wonder why people are trying to build things like this. Also you can stick with your chewing gum there pal, but i personally would use glue in any kind of structural application just to help.


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## smeagol (May 13, 2008)

This has been a great read so far. I was only looking for adhesive advice. There are hundreds of haycaps built in the early 80s and before and they are all standing. 

For those who care it is a howe style truss with a king post. Top chord divided 3 times on a side with 2x4 webbing and bottom chord twice. I like building mine with a kingpost, for i use full length top chords and 1/2 span bottom chords and it is where the most important gusset ties the tension of the bottom chord joint and of the kingpost's to the compression joint of the top chord joint. 

This process only requires a basic understanding of the tension and compression properties. The ratios were in print in finehomebuilding 2 months ago. 

Kent, you should never assume. I makes an @ss out of you and me.


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## CanningCustom (Nov 4, 2007)

Kent, I don't know if you were taking a stab at me there or what but either way, I am no engineer and wouldn't assume the nailing pattern of something like that either way.


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## CanningCustom (Nov 4, 2007)

smeagol said:


> This has been a great read so far. I was only looking for adhesive advice. There are hundreds of haycaps built in the early 80s and before and they are all standing.
> 
> For those who care it is a howe style truss with a king post. Top chord divided 3 times on a side with 2x4 webbing and bottom chord twice. I like building mine with a kingpost, for i use full length top chords and 1/2 span bottom chords and it is where the most important gusset ties the tension of the bottom chord joint and of the kingpost's to the compression joint of the top chord joint.
> 
> ...


Smeagol, either way I wouldn't do it. I am sure you are right that things were built in this method in the 80's' and I am sure a lot of them are still standing. For one thing this isn't the 80's anymore and your building would for sure fail. When you submit for a permit are you just gonna tell them ya don't need a truss print because you understand basic tension and compression properties? Well if ya do let me know how the works out for you. I will still stick with my original opinion, the span is far too long and this is a bad idea.


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## hdavis (Feb 14, 2012)

CanningCustom said:


> Also you can stick with your chewing gum there pal, but i personally would use glue in any kind of structural application just to help.


I'm not sure it always helps. In high stress applications, not having 100% coverage can lead to unexpected stress concentrations and things like PL can keep the faces of the wood slightly apart, weakening the nail pull out strength.


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## hdavis (Feb 14, 2012)

CanningCustom said:


> Kent, I don't know if you were taking a stab at me there or what but either way, I am no engineer and wouldn't assume the nailing pattern of something like that either way.


I think he was getting me in line (more or less).


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## CanningCustom (Nov 4, 2007)

hdavis said:


> I'm not sure it always helps. In high stress applications, not having 100% coverage can lead to unexpected stress concentrations and things like PL can keep the faces of the wood slightly apart, weakening the nail pull out strength.


I understand where you are coming from and I am in no way like a Holmes with the wasting the product just so I can say I used it. Have you ever had a truss fix by and engineer? I have, glue and nailing pattern were spec'd by the engineer.


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## hdavis (Feb 14, 2012)

CanningCustom said:


> I understand where you are coming from and I am in no way like a Holmes with the wasting the product just so I can say I used it. Have you ever had a truss fix by and engineer? I have, glue and nailing pattern were spec'd by the engineer.


I do whatever the engineer says. I haven't had one specify glue, but I'd be inclined to ask for a redesign. No way for me to tell whether the glue job is good or not once it's done, but nailing patterns can be inspected any time. In the event of a fail, if I followed the nailing pattern, it's on the engineer.

And yes, I'll nail and glue lots of stuff, I'm a big fan of glue.


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## CanningCustom (Nov 4, 2007)

lol I think we could go back and forth on this for a while. Ok back to subject, still a bad idea


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## Kent Whitten (Mar 24, 2006)

hdavis said:


> I think he was getting me in line (more or less).


LOL....I'm not getting anyone in line, it is just a bad idea. It is my opinion, but I feel it is a pretty damn good educated opinion seeing all of the dip****s that think it is ok to build a truss and have it collapse on someone below. 

Everyone reads this forum. When you take a second and look at the bottom of the screen, there are times when there are 2000 unregistered visitors to the site at the moment. 

We are sitting here condoning a practice that really should be left to the professional truss company who takes the liability out of it. Especially 9' oc's, 4/12 pitch, and 40' spans. 

Smeagol, there is probably a really good reason why the trusses are not cheap. Maybe there is engineering in it that you do not see. Probably because it is not just a simple Howe truss. 

I would rather assume the worst case scenario than be wrong, especially if someone gets killed from the collapse. This would fall under negligent manslaughter.


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## Rob1954 (Jun 22, 2010)

There's more to it than just tension, compression, and nailing patterns. Shear through the connector plates, especially at the heel is a consideration.


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## cleveman (Dec 28, 2007)

I think we all should have engineering specs on 2x4 walls, 8' high, with 16" oc spacing, two top plates. Every time something is built. I just don't think there have been enough buildings built with this system to say that it is safe.


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## J L (Nov 16, 2009)

cleveman said:


> I think we all should have engineering specs on 2x4 walls, 8' high, with 16" oc spacing, two top plates. Every time something is built. I just don't think there have been enough buildings built with this system to say that it is safe.


I'm pretty sure that assembly is specified in the code book


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## hdavis (Feb 14, 2012)

So, I've been doing some homework. Some of you may know I love old barns. Not the modern ag building ones, the traditional ones. Some were timber framed, some were trussed, some were a combination. The trusses for gambrel roofs were typically made with 2X6s.

On to the modern types - plywood gusseted trusses. The most common reference for site building these ag building trusses covers spans up to 60' and specifies glued and nailed, so anything built following those designs has to be glued and nailed, regardless of anything I said earlier.

Here's the second major point, and it's a VERY VERY major point - the 40' design spaced at 8' with a 3/12 pitch WILL NOT support snow loads here in Maine or anywhere else that has much snow (not even close to supporting it), which includes the OPs location. That is true even using 1600f 2X12 lumber like SYP or doug fir.

My one hard data point says don't do it, it will collapse under snow load.


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## Rob1954 (Jun 22, 2010)

cleveman said:


> I think we all should have engineering specs on 2x4 walls, 8' high, with 16" oc spacing, two top plates. Every time something is built. I just don't think there have been enough buildings built with this system to say that it is safe.


That's the difference between prescriptive design and engineered.

Around here you can build walls up to 10ft tall with the prescriptive method. Anything over 10ft has to be reviewed by an engineer.


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## Kent Whitten (Mar 24, 2006)

hdavis said:


> So, I've been doing some homework. Some of you may know I love old barns. Not the modern ag building ones, the traditional ones. Some were timber framed, some were trussed, some were a combination. The trusses for gambrel roofs were typically made with 2X6s.
> 
> On to the modern types - plywood gusseted trusses. The most common reference for site building these ag building trusses covers spans up to 60' and specifies glued and nailed, so anything built following those designs has to be glued and nailed, regardless of anything I said earlier.
> 
> ...


I am glad you looked. Hard data is better than a gut feeling. I was pretty certain of my gut feeling though. That's a pretty big span. Thank you for looking that up.


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## olligator (Nov 23, 2007)

I thought about this thread today when I was cutting some concrete, running the concrete saw, and really I don't know why. So....

I know that with my engineering background, I could design some badazz trusses. I know that some of the guys here could probably design some trusses that would make mine look like child's play. But for nothing other than liability purposes, if it's my choice, I'll let the engineer handle it. Hard data or not.


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## smeagol (May 13, 2008)

Rob1954 said:


> There's more to it than just tension, compression, and nailing patterns. Shear through the connector plates, especially *at the heel* is a consideration.


 There will be webbing.


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## Tinstaafl (Jan 6, 2008)

I find it interesting that the term "truss" apparently brings out the fear of god in so many people. Stick builders routinely design assemblies that manage the same kind of loads and stresses as pre-fabbed trucked-in trusses.

Not saying that there shouldn't be an engineer's stamp on many of those designs also, but a simple truss is well within the capabilities of a good stick builder.


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## cleveman (Dec 28, 2007)

Hallelujah


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## CanningCustom (Nov 4, 2007)

Tin, I stick frame roofs all the time, but would I attempt to make a freespan truss on 40' span 9'oc with a 4/12 absolutely not. That my friend is gonna end up killing seriously hurting someone.


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## KennMacMoragh (Sep 16, 2008)

CanningCustom said:


> Tin, I stick frame roofs all the time, but would I attempt to make a freespan truss on 40' span 9'oc with a 4/12 absolutely not. That my friend is gonna end up killing seriously hurting someone.


He said "Not saying there shouldn't be an engineers stamp". Building any kind of frame with no permits and no engineering would be crazy, not just trusses.


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