24' Truss design for 4' OC

[LD1]

I am in the design stage for a little garage. Initial plan was to go 20x24....with trusses spanning the 20'.

Then a neighbor offered me some free trusses that were from a deconstructed garage. Problem is I dont know if they were 2'OC or 4'OC and they are 24' span

They are a common truss, and all 2x4 construction. But he only has 6 of them.

I think the building would not look right if the eve wall were only 20' with the trusses (gable wall) spanning 24'. I think it would look dis-proportional. So am considering just a square 24x24 which would require 1 additional truss.

My Google-fu dont seem to be working well this morning....cause I cannot find any info on 24' trusses....either 2' or 4' on center.

Most polebarn trusses around here only need to be designed for 25-30 PSF ground snow load. And I know when I built my shop with 40' trusses....4' OC, they were all 2x4 with a 2x6 top. Same with my buddies 32' trusses. So my question is...with a 4'OC post-frame truss.....at what span is that 2x6 top required?

I know residential trusses, from 10' span up to 30'+ spans are usually all 2x4 construction. But obviously a 10' or 12' truss with all 2x4 is massive overkill.....but its simply because 2x4 is the smallest common dimensional lumber. As well as most residential trusses are built for greater loading anyway cause they are assuming sheathing/shingles and drywall ceilings with more insulation.

My gut tells me an all 2x4 constructed truss is gonna be fine at 4'OC.....but was hoping someone has either built a 24' span building and can share their truss's engineering drawing, or can find one online somewhere that seems to be eluding me at the moment.

 

[deezler]

I would strongly bet that those 2x4 top-chord trusses from your neighbor were 2' on center. The way to know for sure is, to ask or determine if their were purlins going sideways across the top of them. Probably not, right? OSB or plywood roof sheathing can span 2', avoiding the need for purlins.

If I were building a small garage, I would also go with a sheathed roof. Keep them 2' on center, and instead of paying for 2x4 purlins, why not just build 5 or 6 more trusses yourself (or buy more)? Or you could frame half with those trusses and other half with simple rafters, for a partially vaulted ceiling (loft storage?).

24x24 Gable Shed Roof Plans | MyOutdoorPlans

This step by step diy project is about 24x24 gable shed roof plans. This article is PART 2 of the 24x24 shed project, where I show you how to frame the gable roof.

myoutdoorplans.com

How to build a 24' roof truss?

I want to span a 24' shed with a gambrel roof to create an operational space of 16' and I want a design that can be build onsite and installed without a helper. I'm having an impossible time figur...

diy.stackexchange.com

https://www.menards.com/main/building-materials/trusses-i-joists-engineered-lumber/roof-trusses/24-residential-common-truss-4-12-pitch/1871305/p-1482131998903.htm

 

[jigs_n_fixtures]

Contact your County Extension Agent. AG Engineering students design a lot of farm structures and most schools have plan libraries for just about anything you might need to build from chicken coops, to 150X300-ft equipment sheds.

I’m pretty sure Ohio has a publicly accessible plans library.

 

[Roadworthy]

How large was your neighbor's garage before he took it apart? What type construction and roof? Do you have all his trusses or just half of them?

 

[Rustyiron]

You must have a local sawmill, I'd also assume that they were on 2' centers so I'd beef them up with some inexpensive rough sawn.

 

[LD1]

No idea on what the barn size was. And dont want 2' on center trusses. Sheathing is a bank breaker with current prices as well as 2x the number of trusses. This is gonna be typical post frame and metal siding. Not getting fancy.

But I did just look at an old 3-sided equipment building of my parents. 24' trusses...all 2x4 homemade trusses with plywood joints instead of gang nails. Those things are on 8' centers and the building has stood for 70 years or better....So I dont think I'll have any issues at all.

But in any case.....I cant do 24'. Gonna stick with 20' trusses x 24' long. But since these trusses are free, Im gonna use them. Im gonna order 2 end trusses.....lay them on top of these 24' trusses and mark where I need to relocate the bottom cord to. Then I'll just sister 2x4's on both sides of the truss at the new bottom cord location....and cut off everything I dont need. 4/12 pitch....and going 4' shorter.....it should be "exactly" 1' up from the current bottom cord

 

[setxjeff]

This is the website I used to build the trusses for a MIL apartment in my backyard. Glued and nailed with plywood gussets. They came out great and I built a lift pole to set them on the building.

Calculate your own roof truss

The most accurate roof truss calculator you could use with a detailed graphic below your result! Oh, did I tell you that it's free and sendable?

myrooff.com

 

[Rustyiron]

LD I was suggesting just beefing up the 6 that you have and space them 4' if you're concerned about strength.
I wouldn't build anything that involves $hething/osb right now either!

 

[workinonit]

I built my 30' trusses for my shop. I had them designed at a local truss manufacuturer, laid out a template and built 26 of them. I would never put them 4' on center without purlins and probably not even then.

 

[Rustyiron]

It's very common and part of the economy of a post frame building. Many will go 8' that means no perimeter beam - a truss on every pair of posts. This requires a much heavier (but fewer) trusses and your purlins on edge and a zillion joist hangers on each side of the truss, I've never done it.