Small Post-Framed Barn Construction: Opinions Welcome!

[UOFan]

Good morning everyone. I am currently in the process of putting up a 15’x24’ barn. The picture below is about where it stands today:

Now as I finish the odds and ends with the headers (knee brace, nailed and finish my carriage bolts), I need to finish my roof plans.

To be honest, I’m kinda building as I go here...:! I’ve changed my parts of the project every day. It’s just my wife and I putting this up, so we’re not bound to any specific plans.

Here are my current plans for the roof layout:

my plan is to run a 2x8 ridge board across the 4 Center posts, And put up 2x6 rafters 24” OC. I figured 2x knee braces between each would help as well, and I have the extra wood.

We are planning to use galvalume for our roof, and I’ve read so many conflicting opinions regarding purlins vs. Plywood sheathing between the rafters and purlins.

Id appreciate any input about anything regarding this barn building process.


-Located eastern NC, no snow loads

I’ll post plenty more pictures detailing our progress and do a mini write up of our process just for reference, sometime in the near future.

thanks for viewing!

 

[UOFan]

And here are some obligatory photos of my JD 3025e being useful:

 

[LD1]

Interesting building concept...

Cant offer much help other than I would go purlins. If you are gonna spend the money on plywood you can shingle it cheaper. But I also like the underside of the metal exposed to keep it dry.

 

[yanmars]

I do not know how cold it gets in NC but the bare metal on my roof would condense and drip water like rain before I added rigid insulation there later.

 

[Clintock]

What’s wrong with ladden over your rafters and exposed tin in bottom? Like the old barns. No snow here and most barns here are built that way with the exception of metal buildings. Your span is only 15’ so from the ridge board to your bird mouth would be around 8’6” maybe 9’ for a 4-12 pitch. Would be longer depending on your overhang. Hope this makes sense.
It would also be cost effective since you wouldn’t be decking the roof. I built a 16x24 with rafters and ladden. Rafters are on 3’ centers but it’s rough cut lumber. So it’s the full 2x6.

 

[KennyG]

I really like post and beam construction. What is the purpose of the inside posts and beams? Are you going to have a hay loft? I agree with the above, if you are going with a metal roof, forget about plywood.

 

[sea2summit]

My opinion is that it's too small...almost identical size to mine so I have experience

I have bare tin, if I was to do it again I'm not sure what I'd do. It was cheap and easy but I have two or three boards that are getting some water damage from gasketed roofing nails that didn't seal all the way and I haven't gotten up there to seal it. But it has a few years left before I think there's an actual problem.

 

[deezler]

Can you delete the two interior posts before you get much farther? They are always, always gonna be in your way.

Sadly I do kinda agree with sea2 also, it's a bit small. Shoot your Deere will take up half of it right away.

Nice framing work though!

 

[Tinhack]

I really like post and beam construction. What is the purpose of the inside posts and beams? Are you going to have a hay loft? I agree with the above, if you are going with a metal roof, forget about plywood.

I wish I would have used plywood under mine. I had a hail storm with 2" hail that put holes in my steel roof. I think the plywood would have prevented that. But, that too requires more support than my original construction. I made my own double trusses spaced 8' apart with purlins spaced 2' apart across those. (No snow load down here.) I covered that with 10' steel panels. It was cheap and went up fast. It's still in good shape after 20 years--Except for the hail stone holes I re-patch every 3 years or so. The sun does a job on rubber patching.

Here's a picture of the gantry and trolley I built a few years after. It's the only picture I could find of the roof construction.

 

[UOFan]

Thanks for all the inputs. I will probably go with purlins directly against the metal roof. Not too concerned about a little bit of condensation as this will be a goat barn, not a shop or anything.

clintock, your post makes sense...I’m still trying to figure out the overhang. I’m thinking 12”? Any input?

Kenny - are you talking about the 4 Center posts? Those are my Center line for the roof. Basically it’s a 10’ deep by 24’ wide enclosed goat barn, and a 5’ by 24’ overhang out front.

I am going to Center the ridge board on those posts, so I’ll have a 4/12 10’ span on one side, and an 8/12 5’ span on the other side.

 

[Clintock]

I went with 10’ tin. That gave me an overhang of around 16”. Don’t run your ladden or rafters all the way out to end of tin. Water will run uphill. Keep about 4-6” of tin running wild. You’ll have all kinds of suggestions. Best thing is to figure out the most cost effective for what you’re doing but still be structurally sound.
Just a tip. Tin comes in different gauges. Don’t skimp out on the thin stuff.

 

[KennyG]

Kenny - are you talking about the 4 Center posts? Those are my Center line for the roof. Basically it’s a 10’ deep by 24’ wide enclosed goat barn, and a 5’ by 24’ overhang out front.

I am going to Center the ridge board on those posts, so I’ll have a 4/12 10’ span on one side, and an 8/12 5’ span on the other side.

I'm really referring to the center two posts and the cross beams. With a ridge board and collar ties, the roof doesn't need any other support. I guess you are using this primarily for animals. Not having those two inside posts would give you full flexibility to build out pens. I suppose that's academic now, it's certainly a very strong structure and would support a lot of overhead weight.

 

[deezler]

With a ridge board and collar ties, the roof doesn't need any other support.

Or better yet, basic roof trusses..... cheaper, faster, done.

 

[metalbender]

Wow, just in time. I'll be keeping an eye on this one. A hail storm shredded my Shelterlogic tent shed. Having a 12x22 open ended post and metal shed built. Can't believe how expensive it will be.

 

[newbury]

-Located eastern NC, no snow loads

What about ice?
I HAD a 20'x40' metal "carport" located in Mississippi that had been standing for probably 20 years at least. In 10 years the deepest snow we had gotten was 4".
Then last winter we got back to back ice storms, I now have a lot of twisted metal and a 20x40 brick paved open parking lot.
Make sure you have enough slope so you can't get buildup.

 

[UOFan]

I'm really referring to the center two posts and the cross beams. With a ridge board and collar ties, the roof doesn't need any other support. I guess you are using this primarily for animals. Not having those two inside posts would give you full flexibility to build out pens. I suppose that's academic now, it's certainly a very strong structure and would support a lot of overhead weight.

Yes, I basically overbuilt to this because I wasn't worried too much about overall cost...although its piling up! We wanted three smaller (8x10) pens and the covered area out front. The idea is the animals can still be gated and have a roof overhead to protect from the sun/rain, but can hang out in the fresh air! If I were to build it for storage, I would have not included the two center 6x6 posts.

Or better yet, basic roof trusses..... cheaper, faster, done.

The main reason I didn't consider trusses is because I wanted some hands-on experience with rafters. Cost and time are not huge factors in this project, because it is more for fun and getting some more experience. But you're right...definitely woulda been easier..

Wow, just in time. I'll be keeping an eye on this one. A hail storm shredded my Shelterlogic tent shed. Having a 12x22 open ended post and metal shed built. Can't believe how expensive it will be.

A lot more expensive than I thought it would be. $500 in dirt for leveling....way too much on hardware (bolts, anchors, nails and Simpson post brackets). Not to mention the lumber.

What about ice?
I HAD a 20'x40' metal "carport" located in Mississippi that had been standing for probably 20 years at least. In 10 years the deepest snow we had gotten was 4".
Then last winter we got back to back ice storms, I now have a lot of twisted metal and a 20x40 brick paved open parking lot.
Make sure you have enough slope so you can't get buildup.

That's a good point...I haven't experienced any ice storms here in the past three years, so fingers crossed. The slope will be 4/12 on the back side, and 8/12 on the front of the roof (overhang area).

 

[UOFan]

I went with 10’ tin. That gave me an overhang of around 16”. Don’t run your ladden or rafters all the way out to end of tin. Water will run uphill. Keep about 4-6” of tin running wild. You’ll have all kinds of suggestions. Best thing is to figure out the most cost effective for what you’re doing but still be structurally sound.
Just a tip. Tin comes in different gauges. Don’t skimp out on the thin stuff.

Noted regarding the 4-6" of wild tin. That's a good idea, and i'll roll with that.

 

[pmsmechanic]

Noted regarding the 4-6" of wild tin. That's a good idea, and i'll roll with that.

In our area we would never do that. Tin is fastened securely right to the outside edges usually with edge trim. One years worth of wind would have the wild tin ripped to shreds. We also don't use nails for the same reason. Special tin screws only.

 

[marhar]

I went with 10’ tin. That gave me an overhang of around 16”. Don’t run your ladden or rafters all the way out to end of tin. Water will run uphill. Keep about 4-6” of tin running wild. You’ll have all kinds of suggestions. Best thing is to figure out the most cost effective for what you’re doing but still be structurally sound.
Just a tip. Tin comes in different gauges. Don’t skimp out on the thin stuff.

You are spot on when you say! Water will run uphill. I found out the hard way on a barn roof. Next time I will stop the wood 4 to 6 inches back and for added protection I will attach a drip edge to the end of the rafters.

 

[JWR]

A goat barn ... now you tell us ! I was going to say no matter the size you never build big enough but goat barns ?? I have no feel for that.