Another set of Pole Barn Questions

[radioman]

which state are you from ? I didnt see anything in your profile. One thing you might want to consider is wooden I joists as they are much stronger then 2X12's. I see from the first pic your post in the ground is 3 ft . for a pole barn, you might want to go deeper for better bracing of the wind load. Around here where i live, I had to go 40 inches to get below the frost line as part of code. you might be able to get away with 36 inches further south. AS for your floor plan, I see your walls is 12 ft apart on the sides. Perhaps if you wanted to keep your design, you could add 60 ft metal I joists on each side of the 12 ft door. you would need to add posts to support the meteal i joists if your floor plan can afford it. Keep in mind , I am thinking like the northeast due to the snow loads issue for wieght supports.

 

[Gary Fowler]

I just about have this one finished (contractor built) and it has a 30 foot clear span with attic storage. Well I cant get the latest picture to attach so I will do it in another post

 

[Gary Fowler]

Another photo of amost completed 52 x 30 barn

 

[Tscott9330]

EddieWalker:

You didn't say how tall your walls were going to be? Mine are 12 feet and I highly recommend that height. If you went lower, I wouldn't go below ten feet. My roll up door is 10x10 and that works great for getting just about anything into my shop.

I need the doors to be 12' tall, so I worked backward from there and end up with around 13' from the slab to the lowest part of the truss.

The scissor trusses will give you more height in the middle, but they will cost you allot more money to build. When you price them out, be sure to also price out conventional trusses to compare the difference.

You are right, I should get it priced both ways.

You said you want to put the trusses on 2ft centers. Why? This spacing is good for roof sheathing and then shingles, but for a metal room, it's a bit close and wasteful. From the picture, it looks like you have purlins on top of the trusses, which means a metal roof.

I just assumed the truss spacing would be 2' but I am going to rely on the truss company to tell me what I need. From reading your post, I think I would prefer spacing around 4'. I would like to be able to use 2x4's as purlins and nail to the longer side.

I like my purlins to be every four feet. This gives me a very solid roof. My manufactures says I can go further apart, but this is what I like and how I do it. For the small increase in materials, it's worth it. I also like my purlins to be 12 feet long and I stagger them. First row starts at the end of the building, then the next one up goes in one truss and so on. 12 feet also gives me three trusses to attach to. 16 feet would be even better, but I've found that you have to use those 16 ft 2x4' pretty quickly or they tend to start to bow on you while sitting around on the job.

I think in my drawing I had assumed purlins 2' OC but glad to hear 4' is acceptable.


Radioman:

which state are you from ? I didnt see anything in your profile. One thing you might want to consider is wooden I joists as they are much stronger then 2X12's. I see from the first pic your post in the ground is 3 ft . for a pole barn, you might want to go deeper for better bracing of the wind load. Around here where i live, I had to go 40 inches to get below the frost line as part of code. you might be able to get away with 36 inches further south. AS for your floor plan, I see your walls is 12 ft apart on the sides. Perhaps if you wanted to keep your design, you could add 60 ft metal I joists on each side of the 12 ft door. you would need to add posts to support the metal i joists if your floor plan can afford it. Keep in mind , I am thinking like the northeast due to the snow loads issue for wieght supports.

I am in north Florida, so snow load is not a concern.

Thanks for all the pointers guys

Tom

 

[Tscott9330]

Ok, so here is the redesign of the shop. As you will see, I changed to a flat bottom truss, set the poles 4' deep, and spaced the trusses and purlins to 4' OC. I opted to keep the 12' wide doors if I can, I have a boat that I would like to be able to maneuver into the shop, and the extra width will help a lot.

View attachment Shop side view 40' x 60' attic truss Model (1).pdf

View attachment Shop side view 40' x 60' attic truss Model (2).pdf

Let me know what you all think. If I can get the county to OK these, then I will be in business. I can't wait to get started.

Tom

Also, do you see any other notes that need to be added?

 

[EddieWalker]

It's looking better. Two things jump out at me that you may want to consider. First, you have your wall purlins set inside your posts. They attach to the outside of your posts. Idealy, you want them to be long enough to attach to three posts so you can overlap your ends. At 12 foot centers, you'll need them to be 24ft long.

What are you using for siding? If it's metal, then 24ft long 2x6's will work. It also looks like you have them spaceds at 16 inches. With metal, 4 feet centers is all you need. For overkill, you can go three foot, but anything more then that is just excess material.

If you are using a wood material like T1-11, then two foot centers is needed. The same is true for Hardi over OSB.

The other thing that you may want to consider is the change in pitch from your truss to your lean to. Going from one picth to another meansh you create a transition. This may or may not create a problem for you. It's more work at sealing it. How much height do you need at the ends of the roof? If you need the height, go for the change in roof pitch, but if you still have plenty of height, and from what I can tell, you do, then keep the same pitch across the entire roof.

With the same pitch, water will shed faster and you will never have a leaf buildup at the transition of the two pitches. You will never have a leak there or bugs coming into yoru building from there.

Eddie

 

[6sunset6]

It looks like your doors are right up against the ceiling line. Overhead doors need a little space to make the track curve. They do allow for a reduced height with a double track. Best to call the door guys and ask them how much room they need for the height of the door.
I have an 11' door in a 12'4" ceiling height. They said I could have gone a little higher but it works fine . 3" thick but in FL you don't need that.

 

[Tscott9330]

First, you have your wall purlins set inside your posts. They attach to the outside of your posts. Ideally, you want them to be long enough to attach to three posts so you can overlap your ends. At 12 foot centers, you'll need them to be 24ft long.

I recall seeing a few buildings on here with he wall purlins between the post. I was under the impression that this worked well as it framed the interior walls at the same time as the exterior. Is this not the case?

What are you using for siding? If it's metal, then 24ft long 2x6's will work. It also looks like you have them spaceds at 16 inches. With metal, 4 feet centers is all you need. For overkill, you can go three foot, but anything more then that is just excess material.

I am not really sure yet what siding we will go with. The original plan was to go with OSB sheeting covered with Hardie board to match the house, but I am beginning to think that will be a lot more expensive than painted metal. How do the cost Compare? I guess to be safe I can set it at 2' OC.

It looks like your doors are right up against the ceiling line. Overhead doors need a little space to make the track curve. They do allow for a reduced height with a double track. Best to call the door guys and ask them how much room they need for the height of the door.

I know it is close, but I plan to use sliding barn doors on the outside.

 

[EddieWalker]

I recall seeing a few buildings on here with he wall purlins between the post. I was under the impression that this worked well as it framed the interior walls at the same time as the exterior. Is this not the case? .

Anything is possible, but some things are more expensive then others, and some are allot weaker then others. I'm not familiar with what posts threads you are refering to with the purlins between the posts. I have seen purlins on the outside of the posts to attach the siding, and in addition to those purlins, framing studs between the posts that rest on a cement foundation. I've never seen anything like what you drew and don't belive it will work. The weight of the lumber in the middle will sag unless you have it supported by something like a cement footing or addtional lumber in/on the soil.

I am not really sure yet what siding we will go with. The original plan was to go with OSB sheeting covered with Hardie board to match the house, but I am beginning to think that will be a lot more expensive than painted metal. How do the cost Compare? I guess to be safe I can set it at 2' OC. .

Matching the house will probably increase the overall value of your home to some degree, but it's up to you to decide if it's worth the greater expense. Metal is probably your best value for your dollar for siding.

I know it is close, but I plan to use sliding barn doors on the outside.

Sliders are cheap and easy to build yourself. They leak wind and rain, and will let the bugs in with out any resistance. They tend to wear fairly quickly and in a few years, will require fairly regular maintenance and repair. The better you build them, but longer they will last, but it will take a considerable amount of skill and experience to do this.

I have a roll up door and highly recomend them. If you can't afford one, wait until you can. There really is no comparison.

Eddie

 

[MarkV]

You may want to go talk with the county building inspector before you get to set on a plan. What some of the advisors here may not realize is that Florida has really up graded their building codes after the last few hurricanes. Contractor friends of mine in the Tallahassee area tell me they are having to build completely different than in the past to meet the new code wind load requirements.

Also as mentioned, if you have the room going narrower and longer might be cheaper per square foot of building. My experience has been that trusses over 32' jump in cost considerably.

MarkV