Truss or rafters?

[RidgeRyan]

Alright new to this forum just in planning stages of building a pole barn style shelter for my 5th wheel!! Only going to be 16ft wide 36ft long n 14ft high!with metal panel roof..now my question is build my own rafters or buy trusses? now I get that trusses are the easiest way to go but I like to build as long as it not extreamly difficult and I've done a few stick roofs on small shed and a dog house but nothing 16ft wide yet....structurally is rafters and ridge beam 36 ft long strong enough?

If I do decide to buy trusses what kind of spacing would you all suggest? Again it narrower then most pole barns so I'd think 4' o.c would be good!

Thanks in advance for any info

 

[James-W]

Welcome to the forum.

I would go with trusses but I am not familiar enough with pole barn construction to know how far apart the trusses can be. If you have a lot of snow you will probably want the trusses closer together than if you live where you don't get much of a roof load.

 

[jbwilkins]

At 16' I'd just go with whatever is cheapest......based on code/design requirements....

The design of the trusses will dictate the spacing... they may be able to be built to accept 4'o.c. spacing, just depends on your loading....

 

[matt_i]

The dilemma for me would be how to splice the ridge beam over the 36 feet. I was thinking you could put a joint at 18' (or maybe 16' + 20') and buy a couple of LVLs as the ridge. At the joint would need a set of posts/poles, with something like a couple of horizontal LVLs spanning crosswise, so there could be vertical timbers going up to support the splice joint.

Even if pure rafters I'd still want a 16' 2x(6?) every 4-8 feet horizontally at the top as a tension-member to keep the building tied together.

I would price the LVL ridge, rafters, and horizontal ties against a quote for trusses of whatever pitch you select. I would use simpson uplift connectors (H1Z lower) no matter which choice, and a LSU26Z as the top connector if ridge. Add in the price of those plus a couple boxes of the 1-1/2" nails or screws, I personally think the screws are easier as long as it doesn't affect plywood or drywall going in the future.

With the truss there is also the option of driving a long timberlok or grk structural screw up thru the bearing plate into the lower chord to handle the uplift connection.

 

[Cyberbear]

Without considering a snow load, if any, both rafters and trusses will get the job done. The nice thing about rafters is that you can put up one piece at a time for a DIY project. Trusses save some construction time but take more handling time to install. I've seen many rafter roofs sag over the years but trusses are pretty stable and seldom sag. In either case 24" o/c for rafters or trusses is the maximum spacing I'd be comfortable with. Some people have used 4' truss spacing with purlins in between but that seems to be a lesser form of solid construction. JMO

 

[bczygan]

Welcome to GJ!

Please put your location in your profile.

What is your goal?

If it is to gain space in the attic, then then what are you going to use the space for? And what is the roof pitch? Is there going to be much space up there?

If you need a lot of space up there then consider a Gambrel roof. Otherwise you will need a steep pitch, like 12/12 to get much space.

In either case you will need ceiling joists to hold the walls together.

Your members will need to be 2' on center so that flooring or ceiling materials will span.

If you want a truss type construction, then you MUST buy trusses. You don't have the tools, materials or design ability to make them, and neither does anyone else, except a truss company.

For rafters and joists you have two choices, ridge board or ridge beam. A beam that long will be hefty and expensive and an engineered material, probably an LVL. And you will need columns under it, so if there are doors or other openings where they go, you have another heavy beam to design.

Do you know how to use charts and tables to size the beams and rafters and joists?

What are your snow and wind loads?

Bill

 

[bob15]

Rafters. I'm not a fan of truss roofs. I think you lose too much potential storage areas with trusses.....even if that isn't an issue right now, down the road it might be.

 

[mmb617]

I'd use trusses, it's just easier. And I use 24" spacing as I just wouldn't feel comfortable with anything greater, but I do have to consider snow load maybe you don't.

A 16' truss shouldn't be too much for a DIYer to handle as I set the 24' ones on my garage addition by myself and I'm a little old man! Slow and steady gets the job done.

 

[theoldwizard1]

... structurally is rafters and ridge beam 36 ft long strong enough?

If it is a true ridge beam, supported at each gable end by a structural post, it would be plenty strong. (Most rafter roofs are NOT built this way.)
It would require scaffolding and a lot of up and down !

If I do decide to buy trusses what kind of spacing would you all suggest? Again it narrower then most pole barns so I'd think 4' o.c would be good!

They just plug the span and O.C. and a few other numbers into the computer into the computer and it spits out the design/build list. 4' is fine.

 

[James-W]

Rafters. I'm not a fan of truss roofs. I think you lose too much potential storage areas with trusses.....even if that isn't an issue right now, down the road it might be.

Trusses do not necessarily cause you to lose storage space, in fact, they can actually help you get more storage space than you would get from rafters.

I have trusses in my garage and I have lots of storage space up there. In fact, I have a second floor on the garage for storage and it is completely usable across the whole floor. It is 7 feet high so you can walk around easily for most of the second floor.

 

[Adk Mike]

My shop. Is 20 Feet wide. I used rafters. I have 8 foot sidewalls and a 9 and 1/2 foot ceiling. I just put the collar ties up higher and finished the ceiling. No overhead storge by design. It would only collect junk anyway

 

[rburke65]

Update your profile with a location. 16'...18' trusses are not that expensive but that's all relative to ones wallet .... or purse.

 

[James-W]

If anyone is interested, here is one type truss that gives you storage space. There are several other styles that will give lots of storage space as well.

 

[kbs2244]

Why not make you own truss?
Make a few during the week and the have some guys oer on the weekend to lift them up.

The smallest here is 18 foot span.
But the upper clearance will allow for AC units, etc on top.

And it would be easier to line up to.

https://www.ag.ndsu.edu/aben-plans/nd720-1-1.pdf

 

[Ghoster]

My building was completed about a month ago. It is 16 ft wide and 32 feet long with 10 foot high walls. It is a pole barn. I used a roof pitch that matched my house, so you could do a little better than mine if you want storage. That said, once it is insulated, storage isn't really an option. My trusses are 24 inch on center, which is code here for a shingled roof. The upside is that the bottom of my trusses can easily carry the weight of a ceiling.

 

[James-W]

Why not make you own truss?
Make a few during the week and the have some guys oer on the weekend to lift them up.

The smallest here is 18 foot span.
But the upper clearance will allow for AC units, etc on top.

And it would be easier to line up to.

https://www.ag.ndsu.edu/aben-plans/nd720-1-1.pdf

I am not sure that you can really do that. Well, I am sure you could do it if you had the the right equipment. But it is my understanding that the metal "cleats" that hold the trusses together are pressed into the wood using a high pressure press of some sort. I really don't think you can use a hammer and pound those into the wood.

Also, I have not been to a "truss factory" but I am pretty sure they use a jig of some sort when they make the trusses. That way every truss you order is the same. I suspect you would need to make a jig before you make the trusses.

All things considered, I suppose it is technically possible to build your own trusses, but I would have to wonder why you would want to? By the time you purchase all the materials and equipment needed to make the trusses (once you have the trusses sized by "someone in the know" to meet all codes) you could probably buy them cheaper than you can make them. Keep in mind that when the truss company buys truss making materials they do so in very large numbers so they get the stuff relatively cheap.

 

[jbwilkins]

The dilemma for me would be how to splice the ridge beam over the 36 feet. I was thinking you could put a joint at 18' (or maybe 16' + 20') and buy a couple of LVLs as the ridge. At the joint would need a set of posts/poles, with something like a couple of horizontal LVLs spanning crosswise, so there could be vertical timbers going up to support the splice joint.

Not needed (a post at one end would be temporary until the 1st set or rafters are up on that end.... .....The ridge is basically a nailer, as long as the rafters are on opposing sides of it (directly across from each other) and they are fully bearing on it you will be fine....The ridge isn't supporting anything, the rafters are, it's just a bearing point...........

I've seen 24x24 garages using 1x10's for a ridge board with 2x8 rafters.....

 

[kbs2244]

Those truss plans are dated 1932 and published by North Dakota U for farmer built barns.
All you need is a work space, wood, long nails, a hammer, and a strong arm.
And they are code approved.