16 x 24 Pole barn planned for the spring

[IHDiesel73L]

I was searching around for plans for a smaller pole barn with a large gambrel roof loft and a thread about something similar on another forum:

http://www.mytractorforum.com/showthread.php?t=42443

He hasn't logged on in over a year so I don't think he's around anymore, but what I did was study his pictures to try to copy the design. He did mention that his would have to pass code-mine would as well since I live in New Jersey, but from what I heard the inspectors are very willing to work with a homeowner that at least has an idea of what they're doing and how to do it the right way. This is the most helpful picture from the thread:

As far as the pole barn portion itself that's all pretty standard, 6 x 6 poles (though I've read that 4 x 4s are adequate for an 8' wall-can anyone comment on that?), 8' spacing, girts 2' OC, etc... Where my design starts to deviate is the second story. It looks as though he used 2 x 6s for his floor joists. I plan on using 2 x 10s. The reason is because as you can see he has a center support girder which I don't want in mine. I looked up the maximum span for a #2 Doug Fir 2 x 10 16" OC and it gives me 14' - 11". The span between my inside eave rafters (I think that's what they're called?) will be 14' - 7", so I should be good there. I'm not sure of the best way to tie in the floor platform up top to the poles though. Obviously I'll nail each joist into all four eave rafters, but I'm thinking that there must be some better way. Here are two different details:

Now the same idea but with a 2 x 10 top plate over the poles as a more substantial nailer for the joists:

Is one really better than the other? Now onto the loft. I want to use a gambrel truss in order to get the most out of the loft space. I'll be using it for a lot of out of season storage so that I can keep the floor space of the barn for equipment and workspace. Again, I basically copied JDA's design from the pictures-here's what I came up with:

It's pretty simple and uses 2 x 4s and plywood gussets. From what I've heard homeowners are allowed to design their own trusses and the inspector will offer guidance if they think it's needed. This is going to be a pretty simple barn-compacted stone dust floor, sliding door, etc... Also I'll be using steel siding and roofing, so there will be girts nailed across the trusses as well. I welcome any criticism or thoughts on the design.

 

[paulharvey]

All I will add is that 16 x24 seems big when your buying materials and building it, but once you have 2 feet of clutter/stuff/junk on either side, a tractor in the middle, ect; it's fairly small.

 

[EddieWalker]

4x4's are strong enough, but tend to twist and turn too much to be reliable for anything. I would only use 6x6 posts. I would notch the beams into the posts so that the wood is resting on wood. Hanging wood required brackets and bolts. Never use just one or the other. And in some places, bolts alone are not up to code.

I don't think I would try to save a buck on the floor joists with 2x10's. I think 2x12's are well worth the extra expense.

Do not build your roof out of 2x4's!!!! This is going to give you too much movement over time and lead to issues. I like half inch plywood for your gussets. I use liquid nails and deck screws to hold it all together. I don't like nails and try to use screws as much as possible.

Stagger your joints on your purlins. If you set your posts 6 feet apart, use 12ft purlins. If you go 8 feet apart, use 16ft purlins.

Eddie

 

[mjw357]

4x4 is more than adequate for 8' wall, but the example you show looks as if he is adding the new loft/roof to an existing shed. And he has that center beam you don't want. Go with 6x6. I assume you are gonna fill that loft with heavy stuff.

 

[Iowachild]

IHDiesel73L,

Best advice I can give you is to follow Eddie's advice. He is an experienced builder and well respected here. Just for fun I ran 2X10's on a span calculator and I only hit 16" once. That was with Select Structural Spruce-Pine-Fir with 40 psi live load and 10 psi dead load. If you switch to 2X12's you can go 19'6" with the same grade and loads and you can go 17'10" with #2 grade. It's a no brainier, meaning go with 2X12's and you don't have to think about it.:2cents:

 

[bandaidmd]

since your still planning you may want to contact a truss builder for a quote, inspectors love professionally engineered parts and the price might not shock you at all.
Also you may want to check on gluelam's for you floor joists

 

[IHDiesel73L]

4x4's are strong enough, but tend to twist and turn too much to be reliable for anything. I would only use 6x6 posts. I would notch the beams into the posts so that the wood is resting on wood. Hanging wood required brackets and bolts. Never use just one or the other. And in some places, bolts alone are not up to code.

Makes sense-would it be better still to use 4 x 6s like this?

I don't think I would try to save a buck on the floor joists with 2x10's. I think 2x12's are well worth the extra expense.

More on this later.

Do not build your roof out of 2x4's!!!! This is going to give you too much movement over time and lead to issues. I like half inch plywood for your gussets. I use liquid nails and deck screws to hold it all together. I don't like nails and try to use screws as much as possible.

I like the liquid nails and screws idea-would 2 x 6s be adequate?

Best advice I can give you is to follow Eddie's advice. He is an experienced builder and well respected here. Just for fun I ran 2X10's on a span calculator and I only hit 16" once. That was with Select Structural Spruce-Pine-Fir with 40 psi live load and 10 psi dead load. If you switch to 2X12's you can go 19'6" with the same grade and loads and you can go 17'10" with #2 grade. It's a no brainier, meaning go with 2X12's and you don't have to think about it.:2cents:

FWIW the interior span was only going to be about 14' - 10" (16' would be the exterior dimension), but ****, with 6 x 6 poles and a 2 x 12 supported loft I can put a heck of a lot of weight up there :thumbsup:

All I will add is that 16 x24 seems big when your buying materials and building it, but once you have 2 feet of clutter/stuff/junk on either side, a tractor in the middle, ect; it's fairly small.

I hear you, but I'm not nearly as blessed as most here in terms of land and equipment. I live on a 1/4 acre so I want the most storage without taking up the whole yard. In terms of equipment I've got a small JD lawn tractor, vertical log splitter, generator, push mower, power washer, and other odds and ends. However, the space will also serve as a sheltered spot to work on my truck now and then.

Keep the feedback coming!

 

[MacLawn]

Well, IH, now that you posted here too, it's easy - just listen to old Eddie. I think that boy knows a bit. And, I didn't tell you over there, but if agree, build that rascal BIG! Believe me, you'll need the space.

A man can never have enough roofs on his place to put all his junque under.

 

[Hiltz]

An old rule of thumb for any type of pole barn or storage building is to double the size of what you think youll need.

All I will add is that 16 x24 seems big when your buying materials and building it, but once you have 2 feet of clutter/stuff/junk on either side, a tractor in the middle, ect; it's fairly small.

 

[motownbrowne]

In maple syrup production, the rule of thumb is to build your sugar house twice as big as you think you'll need... That way you'll only have to add-on once.

 

[quicksandfarmer]

The loft looks a lot like the construction of a deck. What you're calling eave rafters would be called beams in a deck. The post would normally be notched and they would be bolted to the post. The joists should have blocking or bracing to keep them from twisting, and should be fastened to the beam with hurricane clips or some other way of keeping them from lifting or shifting. This is particularly important if the roof is attached to the joists as wind uplift could take the whole second floor off.

For the size of the beam: earlier we were throwing around a 10 psf dead load and 40 psf live load or 50 psf total. Each section is 16x8=128 square feet, or 6400 lbs. That is held by one beam on each side so each beam has to hold 3200 lbs for the floor plus whatever the roof contributes (maybe 40 psf? Ask your inspector about local snow loads). That's going to be at least two 2x12 or possibly three. This is why you need notching and bolts, there's thousands of pounds on that joint.


If you look at a beam chart for decks you'll find that 16' joist span and 8' post spacing puts you in the far corner of the chart, near the section that says "engineered beam required."

You'll need something to prevent uplift where the rafters attach to the joists or beams.

Each of the center posts is going to be holding 64 square feet of floor (3200 lbs) and 64 square feet of roof (2560 lbs?) or 5760 lbs. You need to make sure your footings are big enough to hold that load, otherwise your posts will sink. A 6x6 has a bearing area of 30.5 square inches, about 0.2 square feet. Check with your building official but a common number for soil bearing capacity is 1500 lbs per square foot. So each post needs about four square feet of footing, that's a 2x2 concrete pad under the post.

There's a lot of info about designing decks on the Internet, I would view this as designing a 16x24 deck with walls and a roof added on.

 

[EddieWalker]

Since the changed the formula on pressure treated wood, I've seen 4x6's twist. I never noticed it before, but you can't even find a dozen of them in a pallet at the store that are straight. Get them home and half of them are turning on you in a week. I wont use them for a client anymore. the only thing I will use are 6x6's. They are heavier, they cost more and they are way overkill. But they stay straight, and for me, that's worth the extra cost and hassle dealing with the weight.

I don't thin anybody mention it, but some builders are using treated 2x6's and laminating them together. Structurally, they are plenty strong enough, but if you put them in the ground, they need to be rated for ground contact. Most 2x6's are not rated for this and it is something you will have to special order. There is an advantage to not having to notch the posts if you go this way, but it's not hard to notch a post and I like the process of notching them, so I like to stick with what works and I can guarantee my clients is going to last.

For the roof structure and the spans you are working with, 2x6's are perfect. I would look at gambrel roof truss designs and see if you want to stick with that design, or add to it. The only concern is snow and wind loads. If that isn't a concern, then the design you posted should be fine.

For me, I've regretted every shortcut I've ever taken, and every time I've tried to save a buck. Spend what it takes to do it right the first time, and you will never have any regrets.

Eddie

 

[lovemytoys]

i used pre made trusses

 

[lovemytoys]

pics i built this last year

 

[lovemytoys]

it cost me about 90 for each truss

 

[YardBikeBob]

Do not build your roof out of 2x4's!!!! This is going to give you too much movement over time and lead to issues. I like half inch plywood for your gussets. I use liquid nails and deck screws to hold it all together. I don't like nails and try to use screws as much as possible.
Eddie

There ya go! Using 2 by 4 stock for roof beams will never hold up. When we bought this place I was sure disappointed with the construction methods on the barn we inherited. The roof is all 2x4s and simple iron nails!


I sure would like to have a long talk with the builder! The way things are going it won't make it another 70 years.

Bob

 

[Hiltz]

In maple syrup production, the rule of thumb is to build your sugar house twice as big as you think you'll need... That way you'll only have to add-on once.[/QUOTE

Im gonna steal that last part from you.

 

[YardBikeBob]

I like the liquid nails and screws idea-would 2 x 6s be adequate?

I would use 'construction adhesive' in the 28oz tubes. Then 2" x .113 galvanized in an air nailer for those 1/2" plywood truss joints. Cheaper, faster. Do the rafter deck and nail it down for a flat spot then screw scrap pieces to the floor as a jig for your gambrel trusses.

Framing nailers are no longer that expensive: 3-in-1 Air Framing Nailer - 10 Gauge

As you're not using roof sheathing, the nailer running 3 1/2s could attach the purlins, too. Sure, a good screwin' might be better but if you're just one guy and only got weekends. . .

Bob

 

[Hiltz]

If your projects size is somewhat confined by your lot size you could cantilever your floor joists 12" out over your walls. Your trusses would then be set 12" farther outside the lower walls. I would think the cost would be minimal and this would give you extra space without compromising the footprint of the building. It would also have the benefit of sheding water off and away from the side walls. Cheers

 

[GPintheMitten]

Consider going taller. A 10 foot eave is more practical for your future lean to.