Pole barn success!

[LittleBittyBigJohn]

Looks good to me. Should work fine. Nice place to store that toy-tractor. LOL

Yeah Yeah "toy tractor" It does just fine with my play dirt

Nice structure, looks like a hefty lumber bill. Did you price out roof trusses? Could have eliminated all the interior poles...

Crazy to see when you southerners just plop poles into holes right over the native dirt. Recipe for failure anywhere up north where the ground freezes, or at least a major headache to try to clean up after the fact. Even so, like jaxs says, you might have a mud pit in there eventually. I would dig a drainage trench around the outside to at least encourage the local ground water flow, and roof water run-off, to go around or away from the storage area.

This was rather expensive for what it is. I looked at trusses. They would have come close to doubling the cost plus the difficulty of getting them set. I figured it would take more equipment and help than I had available. I will monitor water issues and attack them as they arise. I'll add gravel too at a later date.

I do not want to sound negative but I do not see any diagonal bracing. This will leave your barn very easily damaged by wind loads.



The roof allso needs diagonal bracing. This can be added at a relatively low cost. Otherwise your nice looking shed will "rack" or twist in the wind.

I will keep that in mind. However, around here these types of structures don't typically have diagonal bracing. 6X6 posts 3-1/2 feet in the ground 12 times all connected together creates considerable strength. I will watch for signs of "racking" if I see anything I'll add bracing.

I assume they are continuous sheets with no joints. The metal manufacturers don't guarantee against leaks with less than 2/12 slope, but with full length sheets it may not be a problem.

Yes, continuous sheets. It was fun getting 24' sheets home on a 16' trailer...

All-in-all, I just went for - something is better than nothing. I don't have experience building any type of structure and I had a hard time coming up with a design. I napkin sketched this out then put dimensions on it. Eventually found rafter load specs and based my lumber size and length on that and re-drew. Took that sketch to a local lumber/ home building supply yard and had their architect look at it. He said it would work fine. I would have liked more slope on the roof or no poles on the inside. But I stayed with something that I knew I could execute with the equipment and help I had available, rather than test my ability and risk not doing a good job.

 

[s219]

It slopes to the back 1/12 pitch.

As for the interesting framing. No we don't get snow. In Arkansas 10 lb/sqft is called for I exceeded that. I tried to save money by running my rafters the non slope direction and saving money by not having to add lath board. You would be surprised just how little information is available on how to build one of these. I just used my best judgement.

And yes, I will add rock or gravel as time and funds allow.

In terms of loads propagating down through framing, it's really three sideways pole barns married together, and that is not a bad thing, just need to visualize it differently. I suspect you could have used less lumber framing it more traditionally, but then you'd have needed beefier and longer rafters so it's hard to say if it would have been +/- cost difference.

My concern is the lack of purlins across the rafters. Your framing arrangement would work fine with OSB/plywood on top to tie all the rafters together, but for an open metal roof you really need to frame up a grid with purlins over the rafters. That allows loads to be distributed across multiple rafters and it minimizes loads/stresses on the roofing panels and screws. In this case, the roof panels are directly tying the rafters together which doesn't provide any load sharing, and it's going to put stress on the roofing panels and screws (leads to sealing issues and leaks at the screws over the long haul). Purlins help tie everything together and constrain the rafters, which gives tremendous stability and longevity to the metal and screws because they are not handling any loads other than expansion/contraction with temperature.

The recommendation to add diagonals is a good one.

 

[s219]

Eh, if you have twelve 6x6 posts going 3 or 4 feet into the ground, I doubt it will rack very much, or at least enough to care. Obviously he specifically does not want sides on the building, so where would you diagonally brace it, exactly? And the metal sheets on the roof act the same way sheathing does, to prevent racking in that roof plane.

You cannot depend on roofing metal for shear resistance, it's just not capable enough, not to mention that if the panels are going to handle shear loads, the screw points are going to suffer and eventually leak. A proper metal roof should only be handling loads from temperature effects.

I had to run wind calculations for my first pole barn (2014) to get a permit, and it showed two key things. First, using spoils from digging the post holes to backfill the posts would not provide enough resistance against wind racking, even with the poles 4' in the ground. We had to backfill with dry mix concrete to get proper wind resistance. This had nothing to do with uplift (a whole other problem the OP should be concerned about), it was all about loads wanting to rack the poles sideways. If you depend on the post in the ground for a resisting moment, you need to confirm the post backfill method and surrounding compacted soil can provide that.

Second, we had to add diagonals in order to unify the structure against wind loads. This works in conjunction with the post backfill, they go hand in hand. You can probably get away with one or the other in certain cases, but with a large enough structure both will probably be required.

If for some reason full diagonals are not appropriate, using small corner diagonals (a corner buttress) between the posts and beams is a very good substitute. Make them as long as feasible without impeding access. Here's a recent pole barn I built using both:

 

[LittleBittyBigJohn]

In terms of loads propagating down through framing, it's really three sideways pole barns married together, and that is not a bad thing, just need to visualize it differently. I suspect you could have used less lumber framing it more traditionally, but then you'd have needed beefier and longer rafters so it's hard to say if it would have been +/- cost difference.

My concern is the lack of purlins across the rafters. Your framing arrangement would work fine with OSB/plywood on top to tie all the rafters together, but for an open metal roof you really need to frame up a grid with purlins over the rafters. That allows loads to be distributed across multiple rafters and it minimizes loads/stresses on the roofing panels and screws. In this case, the roof panels are directly tying the rafters together which doesn't provide any load sharing, and it's going to put stress on the roofing panels and screws (leads to sealing issues and leaks at the screws over the long haul). Purlins help tie everything together and constrain the rafters, which gives tremendous stability and longevity to the metal and screws because they are not handling any loads other than expansion/contraction with temperature.

The recommendation to add diagonals is a good one.

Are you calling purlins and lathe board the same thing? Can I add a few on the bottom of the rafters to help with that? I saw some pictures of lean-tos with the framing like I did this one. That's why I even tried it.

I will add corner buttresses. I honestly forgot about those.

Oh, also there are 2 bags of sakrete in each hole. Hole, post, sakrete then dirt (mostly clay) tamped down

 

[deezler]

s219, kinda sound like you are describing hurricane level wind resistance. Perhaps overkill here, but, you're not wrong. I think adding a slew of corner buttresses like you mention would be a great way to gain some strength.

 

[s219]

Are you calling purlins and lathe board the same thing? Can I add a few on the bottom of the rafters to help with that? I saw some pictures of lean-tos with the framing like I did this one. That's why I even tried it.

I will add corner buttresses. I honestly forgot about those.

Oh, also there are 2 bags of sakrete in each hole. Hole, post, sakrete then dirt (mostly clay) tamped down

Sounds like you're good with the concrete post hole backfill, and corner buttresses will really help tie it all together by bracing up the corner joints so they can't move.

If you detect movement in the rafters or noticed that walking on individual rafters felt overly bouncy in the middle, then you can add purlins to the underside of the rafters to tie them together. I'd probably start with a single one down the middle of all the rafters to tie them together at the point where there would be the most deflection. Use a good structural screw or deck screw.

Alternately, you can use blocking nailed between rafters. Could just alternate 2x6 blocks (alternate so that you can nail the ends easily). However it's done, the goal is to join the framing members so they can work together to spread out the load.

 

[LittleBittyBigJohn]

Sounds like you're good with the concrete post hole backfill, and corner buttresses will really help tie it all together by bracing up the corner joints so they can't move.

If you detect movement in the rafters or noticed that walking on individual rafters felt overly bouncy in the middle, then you can add purlins to the underside of the rafters to tie them together. I'd probably start with a single one down the middle of all the rafters to tie them together at the point where there would be the most deflection. Use a good structural screw or deck screw.

Alternately, you can use blocking nailed between rafters. Could just alternate 2x6 blocks (alternate so that you can nail the ends easily). However it's done, the goal is to join the framing members so they can work together to spread out the load.

Got ya. That sounds doable. It's super solid right now. I will go ahead and add a purlin to the middle underside of each. I thought about that before I put the metal on, but there wasn't much movement, so I didn't mess with it.

I really appreciate the input. Wish I had been able to talk with you before hand. I'll know next time. I'm not super worried about this one. It would be different if it was going to be a workshop or some other type of enclosure that is expected to be 100% perfect. This is just an umbrella for equipment, although I will eventually "enclose" 3 sides. Eventually I will build, or have built, a large shop. Enough of what I have under this will go in it, that this will probably be an animal barn. I may make one of the sections into a sort of tack room or sort of shed later also.

 

[EddieWalker]

Some really good advice on bracing. When first built, wooden structures can feel very solid, but over time, they loosen up. If you used pressure treated wood, it will shrink as it dries and really loosen up. If you used nails, it will be even noticeable. Best thing to do is reinforce it everywhere and max out your diagonal bracing. Triangles are the strongest shape, the more the better!!!

Once it starts to move, it will be a lot harder to stiffen it up. It will move. Every building moves. Minimizing the movement will allow add to the life of the building. The first area that you will see problems from the movement will be in the screws holding the metal on. They will begin to leak as the metal around the screws becomes bigger.

 

[s219]

Got ya. That sounds doable. It's super solid right now. I will go ahead and add a purlin to the middle underside of each. I thought about that before I put the metal on, but there wasn't much movement, so I didn't mess with it.

I really appreciate the input. Wish I had been able to talk with you before hand. I'll know next time. I'm not super worried about this one. It would be different if it was going to be a workshop or some other type of enclosure that is expected to be 100% perfect. This is just an umbrella for equipment, although I will eventually "enclose" 3 sides. Eventually I will build, or have built, a large shop. Enough of what I have under this will go in it, that this will probably be an animal barn. I may make one of the sections into a sort of tack room or sort of shed later also.

If the roof feels beefy now, that is a good sign, since walking on it creates a “live” load that is a good diagnostic of problems (that can later affect dead loads). Really the main worry, as Eddie has mentioned, is dealing with movement of the structure as the wood ages. So I think putting some purlins on the underside will be beneficial for that reason alone. Lumber loves to move over time. Some of the worst movement can happen when it’s fastened on the ends only, with the middle left to wander. It will do some crazy things. If you can also constrain it in the middle you will add stability and predictability over time. Many times, framing is as much about getting the wood to behave as it is about supporting loads. A good structure takes both into account and you sort of arrive at a sweet spot where the design looks right to the eye.

 

[LittleBittyBigJohn]

I'm working on ordering gravel for the inside. I'm getting some for a parking pad/ driveway by the house, figured I could do this at the same time. Any particular notes? He has a 15 yd truck. 1 load should give me about 6" depth give or take.