Pole build: Structural screws vs. pole barn nails/carriage bolts

[rbstern]

Hoping to get some feedback on use of Spax-type structural screws vs. traditional pole barn nail + carriage bolt fastening. Application would be for 2x12 girder to 6x6 post attachment. It looks like both 1/4 and 5/16 diameter Spax (and other brand) structural screws substantially exceed 40d pole barn nails for both shear and pullout strength.

The girders would still be supported by nailed 2x12 blocks, with a typical nailing pattern.

Thoughts and experiences appreciated.

 

[3Ts]

The building trades are continuing to improve products and methods. Most of them really are improvements. Personally, I prefer the new technology stuff because it makes it quicker and easier primarily, but typically at the same time it also provides an improved product. I have used the structural screws and found them to be easier than the large spikes. I use nails if my nail gun can handle them (and no bright nails, they have to be coated to resist rust even for temporary stuff), but large fasteners, I use the structural screws and a battery powered impact wrench.

Something else to consider - nails should be used in shear applications only, their pull out force is relatively low. Screws over come the pull out problem. Shear strength is typically related to cross sectional area of fasteners, however, with new alloys, that is no longer true. I've used 3/16" structural screw to replace a 3/8" lag screw and it holds better , is easier to drive, doesn't need a predrilled hole, and is less obtrusive than the lag screw.

 

[aczlan]

Every pole barn structure I have seen built in the last 5 years or so has had nails from a pasalode or air nailer to get the 2x12 to hold still, then construction lags to fasten it in and hold load.
I don't think there's many people still using pole barn nails to fasten structural members on pole barns.

Aaron Z

 

[Lineman North Florida]

I like bolts to fasten the headers to the post, might take a little longer but I don't think you can beat it.

 

[mikester]

I'd prefer bolts to screws. My only issue with screws are the questionable quality fasteners being imported from china. No all fasteners are made equal, some brands you will be snapping off screw heads driving them only part way in. Air nailers are faster.

 

[s219]

I always use 1/2" through bolts for header to post connections (and notch the posts). Some of the new timber screws are structural rated and should be fine. Just read the fine print to make sure they are structural screws and not simply for landscape timber work.

I have been using GRK structural screws in various places and really like them. Both Amazon and Home Depot have decent prices on them (cheaper to buy in bulk).

In the photo below, I used 1/2" bolts for header/post joints, but everything else is a GRK structural screw, ranging from #10 to 1/4" to 5/16" sizes.

 

[aczlan]

I'd prefer bolts to screws. My only issue with screws are the questionable quality fasteners being imported from china. No all fasteners are made equal, some brands you will be snapping off screw heads driving them only part way in. Air nailers are faster.

GRK and FastenMaster (TimberLok/LedgerLok) seem to be good.
Points to GRK for using standard Torx bits.
Lowes also carried some other brand that looked like GRK, but the metal resembled cheese when you went to drive it in (Spax?).
Air/Pasalode nailers are faster, but dont get the strength that a bolt or lag does.
Structural lags are way faster and (from our destructive testing at work ) a pair of structural lags through the end of a 2x into a 4x4 or larger post will hold as well as a thru bolted connection (ie: the end of the board fails before the screws rip out).

Aaron Z

 

[Wood_Butcher_Dav]

I just bought a box(? 5 lbs.) of #10s and paid $59.55 at RP Lumber

Dave

 

[deezler]

My 30x36 pole barn has 4x GRK structural screws holding the LVL or 2x12 truss-carrying headers to each 6x6 post. I'm happy that my builders went this way, just wish they would have been a bit more careful lining up and spacing out the 4 screws in each post. Kinda looks like they were drunk

 

[EddieWalker]

I live in an area where Code doesn't exist, so I try to keep up with the changes from reading as much as possible. Structural Screws are replacing lag bolts, and in some cases, Carriages bolts in deck building. I've never read anything, anywhere on what is Code for a barn.

But Structural Screws are not to be used for load bearing beams. Anything load bearing needs to have a metal bracket designed for that load, (joist hanger) or supported by solid wood under it. And this seems to vary around the country, even with solid wood under the beam, a metal bracket may be required. Most Inspectors will fail you if you rely on Bolts or Structural Screws to support a beam. The reasoning is that the beam will split in those locations.

There are several types of Structural Screws. Be sure to buy the type that applies to your application. It's a bit confusing, and there are a lot of options. Usually the most expensive are the strongest.