Pole barn: bolt/screw/nail requirements

[rimshot]

I'm starting a small 28' X28' pole barn. I live in Northern Michigan's snow country where live load requirements for truss'se happen to be 70 lbs loads. It blows my mind that engineered plans for pole barns call for simply nailing the doubled 2 X 12" truss carrier to my 6 x 6" Posts. I have seen this work by reviewing countless examples of existing pole structures with much larger spans than mine. Darn few have fallen down so I'm willing to go ahead and connect in similar fashion.

My question is there are some pretty nifty new screws on the market with high shear strength. They make any length practically in high strength 1/4, 5/16 or 3/8" HEX DRIVE screws. So which size and how many do I use. The darn things are about .75 cents a piece so I don't need any extra. By the same token, These truss carriers need something substantial for this connection.. I would just as soon not mortice a notch in each pole.

This structure calls for truss spacing to be 48" on center with every other truss atop a post.

Thanks ain advance for any advice.

rimshot

 

[Storm56]

Good luck with the new project. I just built a 20x40 pole style equipment shed. Unless you are using glue lam posts which have white untreated wood above grade, be sure to to use double galvanized nails as the new pressure treated wood will eat most other nails.

Also a little trick I use for peace of mind is to take a piece of 2x6 and put it vertically under the headers on the poles and put extra nails in that to add support. as I am kind of like you and like to see a little extra support for those headers when dealing with large snow loads.

Good luck with the new project!

 

[teg]

"...Also a little trick I use for peace of mind is..." ...I use 1/2" bolts and notch the post.

 

[flusher]

"...Also a little trick I use for peace of mind is..." ...I use 1/2" bolts and notch the post.

Me too. Use 16d nails on the girts and purlins. Use 1/2" lag screws on the knee braces. Examples:

An equipment shed from 2 years ago



A gazebo finished yesterday

 

[cspot]

Good luck with the new project. I just built a 20x40 pole style equipment shed. Unless you are using glue lam posts which have white untreated wood above grade, be sure to to use double galvanized nails as the new pressure treated wood will eat most other nails.

Also a little trick I use for peace of mind is to take a piece of 2x6 and put it vertically under the headers on the poles and put extra nails in that to add support. as I am kind of like you and like to see a little extra support for those headers when dealing with large snow loads.

Good luck with the new project!

I did the same thing with the 2x6 and I also used two 1/2" carriage bolts thru both 2x12 and the post. Make sure to retighten after a couple months and the wood dries out a little. I believe mine called for galvenized pole barn nails which I think were a 20 penny nail. I also threw a few of these in there too.

 

[timswi]

Mine is nailed together and has taken some serious snow loads. On both of the buildings that I've buit, a 28x30 and the current 30x48, I have put vertical scabs from the header to the base between all of the purlins. This will helpd distribute the header load. The first building is 18 years old now, and no problems what ever. The new one is about 8 years old.

I also made the header on the load side a box beam buy placing a 2x6 in between the inside and outside headers. This helps with deflection and twisting.

Nothing wrong with notching and/or bolting either.

 

[Lt CHEG]

I like lag bolts and notching too, but if you really think about it from a physics standpoint, you probably don't need anything more than nails. If the trusses are sitting on top of the posts gravity is doing a pretty good job of pushing the truss on top of the post. The more snow load the more down pressure. Essentially the brackets just prevent shear and torsional stress from separating the components. I think it's been said here once before that theoretically if there was no wind and other sources of shear forces you should be able to have a house stay together just by gravity with no nails or screws. Since we live in a world with other stresses obviously nobody should try that, but I think the point is that you probably don't need a whole heck of a lot of metal in your fastener for those brackets to do their job correctly.

 

[rimshot]

Thanks for the points of view. here's some pictures of the way it looks today. Erection should start in a week or so.

rimshot

 

[BHD]

if your fastening into green treated lumber, you will want to use extra heavy galvanized or stainless steel fasteners, regardless if you use bolts or nails,

The New Pressure-Treated Wood - Fine Homebuilding Article
according to fine home building they appear to be suggesting the use of only stainless steel,

check with the manufacture of the treated lumber for proper fasteners to use and materials,

 

[bobodu]

When I built mine, I lagged a 2x8s around the inside and outside of the posts. Then I filled the gap on top with a flat 2x4. Gave me a large area to nail down the trusses.