40x60x16 pole barn with 12 truss spacing?

[mitch f]

Hi everyone, I am hoping to build a 40x60x16 pole barn on my property with 12 foot spacing on the posts and trusses. I can’t for the life of me find any plans that I can purchase (without paying an architect some ridiculous amount of money) that have the specs I’m looking for. I have seen pictures of these buildings and have seen a couple in person over the years so I know it can be done but getting my hands on some prints to help me with my build is proving to be very hard. I can find plenty of plans for 8 foot spacing but I am hoping to put a loft in the back 12 foot wide bay at some point.

I have my own saw mill and am building on an ag permit in Oregon so I don’t necessarily need stamped prints I just want something to go off of so that I can build a strong, sturdy shop with. If I need to overbuild a little to make up for the extra spacing I am looking for that’s fine.

If anyone on here has any ideas or someone I can contact I would very much appreciate it!

Thanks
Mitch

 

[Bert_]

A single truss could probably be made to that spec. If you're only needing one bay to be 12 ft it might be easier to to use trusses designed for 8-ft spacing and then just double two of them for the back 12 ft bay.

 

[billconner]

Hansen Buildings seem to like 12' spacing but as I understand it, they use two trusses at each post, similar to Bert's suggestion. Makes sense. They put purlins in joist hangers flush with top of truss for roof then.

Are you making your own trusses from lumber you milled?

 

[gsmith22]

the further your truss spacing, the greater structure you need between the trusses. also, the greater load you get on each post which can create larger footings. I suspect the 8' dimension is most common because it is a happy medium between light structure between trusses and minimize footing sizing.

 

[billconner]

The greater the spacing the few parts and pieces and less labor. If your paying for labor, the additional material cost is likely ess than labor savings. Footings, yes larger but fewer, probably less concrete overall. Purlins - 2x6 or 2x8 instead of 2x4 or 2x6? Hardest part is the engineering. Just saying....

 

[larry_g]

Custom Pole BuildingDesign Center - M&W Building Supply Co. Feedback Survey

mwbsc.com

You might check with the above company out of Canby OR. I worked with them for my building and years ago they had a design and engineering department. I got a good plan set with my building from them.

 

[gsmith22]

The greater the spacing the few parts and pieces and less labor. If your paying for labor, the additional material cost is likely ess than labor savings. Footings, yes larger but fewer, probably less concrete overall. Purlins - 2x6 or 2x8 instead of 2x4 or 2x6? Hardest part is the engineering. Just saying....

yes all of that is true, but no one building one of these wants to pay for engineering (the actual engineering isn't 'hard') or generally pay for anything. so 12' spacing is far less common, everyone copies what everyone else did at 8' spacing, and so on.

 

[Firebrick43]

Larger spacing really doesn't save much anymore.

Clearer old growth lumber used to be much more common and cheaper therefore the larger pieces for higher loaded trusses could pencil out. The reason plans are not available because its very critical to have excellent graded lumber not something you milled on the back 40, there is little margin for error or unseen defects.

And as Mr Conner pointed out larger spans between trusses also requires larger 2x6 or 2x8 lumber on edge for purlins as well.

With todays lumber quality (or lack of) it makes more since to spec lighter capacity trusses closer together on center and 2x4's on face for purlins.

 

[billconner]

6 trusses versus 2 in 12' (or 4 versus 2 in 8') plus multi-ply headers just doesn't justify the advantage of purlins on the flat for me. And that's ignoring the possibility of the useable tall space between trusses when there further apart. I'm glad we all have the choice.

 

[jack stand]

12' spacing;

Diagonal wall bracing will be more difficult and have many times more importance in the structures integrity

All of your roof system (16'+ in the sky!) will be much heavier members and again diagonal bracing will be much more complicated.

Roof purlins will have to "stand on edge" and either be blocked (above the trusses) or hangared (in between the trusses).

Now if you're fully sheathing the complete shell you're bracing problem go's away but what have you gained. (12' vs 8')
To me, if you're sawing your own lumber, your material costs will be very low and this work is obviously done on the ground whereas ******* 2x8x12' purlins (green lumber) 17' to 25' up onto the roof deck, placing (into joists hangers*) and fastening and then blocking).... I just don't understand your aversion to a more reasonable post spacing.

"If I need to overbuild a little to make up for the extra spacing I am looking for that’s fine."

The way I look at your quote above is get your "overbuilt" out of the way on the ground with your "foundation"... the posts, and then you can fly up high.
A couple of other considerations are;
*Full dimension sawmill lumber is not compatible with standard "joist hangers"
Everyday nail guns might take a 3 1/2" nail. Those are just "tacks" to a full 2" thick board.
You have a mill, you know how heavy your lumber is while standing on the ground. Imagine being 20' up in the air standing on the 2" edge of a 2x8-10? 12' long, on a pitched roof trying to manipulate it into place.
All of my seemingly negative comments come from experience. I built a much smaller (and lower) 38x40x12 building for my sawmill and sawed out my materials, I worked alone and cut hemlock from my land.
Back to your actual question (kinda), if you were to bite the bullet and order trusses, they will do your roof engineering for you regardless of your spacing.

 

[mitch f]

Hansen Buildings seem to like 12' spacing but as I understand it, they use two trusses at each post, similar to Bert's suggestion. Makes sense. They put purlins in joist hangers flush with top of truss for roof then.

Are you making your own trusses from lumber you milled?

I will look into them thank you and no I am not planning on making my own trusses. Really I plan on buying all the lumber for the project I can I was just saying if I needed to I could mill some extra large posts if I needed too for some reason.

 

[mitch f]

The greater the spacing the few parts and pieces and less labor. If you’re paying for labor, the additional material cost is likely ess than labor savings. Footings, yes larger but fewer, probably less concrete overall. Purlins - 2x6 or 2x8 instead of 2x4 or 2x6? Hardest part is the engineering. Just saying....

Ya I understand and I get it but I was getting quotes for a simple 40x60 with no interior walls for $6k or more where as the plans I have now with the 8ft spacing only cost me 200$..

 

[mitch f]

Custom Pole BuildingDesign Center - M&W Building Supply Co. Feedback Survey

mwbsc.com

You might check with the above company out of Canby OR. I worked with them for my building and years ago they had a design and engineering department. I got a good plan set with my building from them.

I actually did check with them and they said it wouldn’t be a problem and would sell me a kit for what I’m looking for for about 40k and I might go that route. but like everything these days I’m trying to save as much money as possible and I know I can get all the parts local for a little cheaper I just need some plans and they were not willing to just sell me the prints unfortunately.

 

[Shootinok]

If you’re only needing one bay for the loft, do the other bays need to be 12’ span also?
And, If you’re looking for ceiling height, could you use a scissor truss and close the spans some?

I wanted the most height I could get from 10’ top rails so I reached out to a truss manufacturer and they designed my trusses. Then built them cheaper than I could.
I have a loft on the end above the door. They also designed those trusses.

40’ clear span is massive.
I have a 24’ span and I put my trusses at 5’ — definitely not as big a structure as you’re building, but here’s a pic…

 

[billconner]

Embedded posts and metal siding will solve lateral bracing. Whether a bunch of 2x12s for headers (" truss carriers" to some) is easier than 2x8 purlins can be debated. And of course for overhead doors, jack's and headers and cripples and odd post spacing.

Maybe because I'm so used to 20' or 24' column spacing it doesn't seem so alien.

If you need to buy just plans, more cost. But I'm pretty sure the truss fabricator will charge less for 2 beefier trusses than 6 not so beefy, and that's with the engineering. Where I live, pretty sure I could do the rest of the plans prescriptively.

Not familiar with M&W. I just went down the road a ways with Hansen and felt they were really on top of it. They'll sell just the kit or as much of it as you want, or find builders as well. I was going to go with frame and roof, and do my own board and batten siding and doors and windows (before I decided to stick build and have an attic and one column dead center - to save about half the cost.)

 

[mitch f]

12' spacing;

Diagonal wall bracing will be more difficult and have many times more importance in the structures integrity

All of your roof system (16'+ in the sky!) will be much heavier members and again diagonal bracing will be much more complicated.

Roof purlins will have to "stand on edge" and either be blocked (above the trusses) or hangared (in between the trusses).

Now if you're fully sheathing the complete shell you're bracing problem go's away but what have you gained. (12' vs 8')
To me, if you're sawing your own lumber, your material costs will be very low and this work is obviously done on the ground whereas ******* 2x8x12' purlins (green lumber) 17' to 25' up onto the roof deck, placing (into joists hangers*) and fastening and then blocking).... I just don't understand your aversion to a more reasonable post spacing.

"If I need to overbuild a little to make up for the extra spacing I am looking for that’s fine."

The way I look at your quote above is get your "overbuilt" out of the way on the ground with your "foundation"... the posts, and then you can fly up high.
A couple of other considerations are;
*Full dimension sawmill lumber is not compatible with standard "joist hangers"
Everyday nail guns might take a 3 1/2" nail. Those are just "tacks" to a full 2" thick board.
You have a mill, you know how heavy your lumber is while standing on the ground. Imagine being 20' up in the air standing on the 2" edge of a 2x8-10? 12' long, on a pitched roof trying to manipulate it into place.
All of my seemingly negative comments come from experience. I built a much smaller (and lower) 38x40x12 building for my sawmill and sawed out my materials, I worked alone and cut hemlock from my land.
Back to your actual question (kinda), if you were to bite the bullet and order trusses, they will do your roof engineering for you regardless of your spacing.

I appreciate your comments and if they are “negative” I want to hear them! This is my first build on my property and just want to do it right!

I am planning on fully sheeting it and at some point possibly insulating it with a low r value insulation.

I definitely am planning on getting trusses that are engineered for it and don’t mind if I need to double up the trusses to get the spacing I am looking for. I just would like the 12ft spacing for everything to be a bit more open and give me more room up high if I decide to do any more than just the one bay loft I have planned in the back now.

 

[Bert_]

40’ clear span is massive.
I have a 24’ span and I put my trusses at 5’ — definitely not as big a structure as you’re building, but here’s a pic…

No need to give people the wrong idea. 40 ft span is extremely common and no big deal. 60 ft span with wood trusses is common. Even 80 foot span is doable. I don't see wood trusses much wider than that but I'm sure they are out there.

 

[Bert_]

I appreciate your comments and if they are “negative” I want to hear them! This is my first build on my property and just want to do it right!

I am planning on fully sheeting it and at some point possibly insulating it with a low r value insulation.

I definitely am planning on getting trusses that are engineered for it and don’t mind if I need to double up the trusses to get the spacing I am looking for. I just would like the 12ft spacing for everything to be a bit more open and give me more room up high if I decide to do any more than just the one bay loft I have planned in the back now.

I don't know your location or what your plans are for the building. If putting in a ceiling and insulation is ever in your plans I would not go 12 ft for the whole building.

 

[Firebrick43]

Will you accept center post on your loft?

If you have a center post with a footer under your loft it make the size of the floor joist much smaller and less bouncy.

If you then take those center post all the way up to the ridge and set a ridge beam you could use rafters in that one section above the loft using 2x12’s on 24” centers.