First Pole Barn Build

[md9nyc]

Hello all,

After living in NYC for the past +10 years, I finally purchased enough land to start my small farm in Westchester County, and couldn't be more happy. I'm in the midst of planning a 30'x24' pole barn; the 24' width will be split between three stalls and a lean-to. I would like to have a loft over the stalls and lean-to for storage (nothing too heavy), and that is where my questions lie. My joists will span 12' between my headers (I was planning on using 2x12 headers & 2x10 joists @ 16 oc). My question is, would I be better off with the joists on top of the headers or should I use joist hangers between the headers? I plan on notching the 6x6 poles for the outer header to help support the rafters. If I were to use joist hangers, should I notch the inside header as well? That will only leave me with 2.5" of "pole" sandwiched between the inside and outside headers - even less if I opt to use an LVL. The other option would be to bolt the inside header to the 6x6 and run a PT 2x6 support down the pole to the concrete footer. I have real concerns with using joist hangers in that a 12' span joist may sag enough to pull them out and hope that my worries can be alleviated by your insight.

Now thinking about it, I had wanted to notch the 6x6 for the rafters on each side of the poles. Is that overkill of the outside header is notched?

Before I started my career, I was a framer and am fully capable of building a stick frame house. Pole barn construction is new to me and any help would be greatly appreciated. Many thanks in advance and I look forward to posting about the progress. Once the pole barn is done, I can focus on a tractor...

 

[s219]

Well, you can probably look at the Simpson website and see what sort of rating they give for their hangers. But if my home is any judgement, we have 20' floor spans with 2x10 joists sandwiched between LVL beams, and the joists are sitting in hangers. The hangers have a bottom ledge that is a good 2" deep. As long as the joists are sized/spaced properly for the load, they will never deflect or sag enough to come remotely close to bowing out of the hangers. The hangers are heavy metal (Simpson makes various grades for the required support loads).

As far as notching, on my pole barn, and the addition, I use a double 2x12 header for the eave walls. One of the headers is notched into the poles and the other is nailed onto the first header and then both through bolted to the pole. This leaves the outer header inline with the wall girts (which just get nailed to the pole). You're talking about a slightly different reason, but I'd still say notching one header is enough. The real truth is based on how much surface area is needed for the wood grain (of both the notched pole and the header) to transmit the loads without the grain compressing. There are calculators for all of that, which you can consult. The calculator will tell you how much bearing area is needed for wood members in order to prevent compressing the grain unsafely.

Lookup "wood structural design data" on google for a good reference.

Good luck!!

 

[s219]

Here's the WSDD:

http://www.awc.org/pdf/codes-standards/publications/wsdd/AWC-WSDD1986-ViewOnly-0301.pdf

 

[jfh28]

if the joists are deflecting that much to pull out of the hangers then you have severely under designed the size of the joists for the loading and they will fail.......I'd suggest that you have a licensed professional run the calculations for you based on how you are planning to use the spaces....that will dictate size, span and connections........Jack

 

[GLyford]

If you are used to stick framing, you likely already know this:

If the joists are deflecting enough to pull out of the hangers, they may also be twisting/tipping over in order to bend easier. You can stop a lot of that by putting in blocking midspan to keep them upright and in position. Even though it doesn't increase the rated load capacity, it takes out a lot of the bounce. If you put the joists on the headers instead of in hangers, then either blocking between the ends or adding a rim joist to keep the ends vertical is also a very good idea (the hangers basically do that for you if you use them).

 

[Woody65]

I just built a similar sized pole barn last year (32x40) and your required to notch the top of the 6x6 to accept the 2x12 header for the trusses or stick frame roof and joists. I would have no issues with using hangers for that small of a span. The 2x10 joists are plenty for a standard live load over a 12' span. Here are some pics of mine if it helps at all. Good luck and keep us posted. Pics are a must