Pole Barn - Question on Top Plate approach

[Dave5264]

Rather than Hi-jack the other post on pole barns, Ill ask a seperate question here.


Im currently drawing up plans for a small pole shed/barn 26 x 34.

My current Drawing shows the top plates will be laminated 2x8 (ie doubled up with the joints off set for strength). These Laminated beams will sit directly on top of the 4x4 Posts.

my question is:

Which way is better, my plan per above or... to sandwitch the 4x4 posts instead. I figure the strength of the beam/post combo is better when laminated and on top vs seperate and held via a carriage bolt.

Opinions please & Thanks

 

[MikeD74T]

I tore down a barn for salvage 10 years ago. It had 6x6 posts with 2x10 on each side capped with a third 2x10 that the trusses were anchored to. Posts were spaced on 12' centers & supported 50' span.MikeD74T

 

[beppington]

What I've always seen is a 2x4 laid flat as a sort of "lower top plate", then set your beams on that, then add an "upper top plate" on top of the beams. That upper one would be the equivalent of a standard home's "top plate".

Did I understand your question right?

 

[Verticaltrx]

I have several ways of doing this depending on the size of the shed. Normally I would use 6x6 posts even for a small barn.

First method (and this would be only for a very small shed) is to just bolt the 2x6, 2x8, what ever to the outside of the post.

Second method is to bolt the 2x8's, x10's what ever to each side of the post. Nail them first using good heavy ring shank nails, then use 1/2" or larger bolts all the way through.

Third method is to notch out the top of the 6x6 on one side 1.5" deep. Then laminate your 2x's together and place them with one being on the notch. This gives you the doubled up strength, plus the strength of sitting on the notch. Also makes the outer edge 1.5" away from the post so it will line up with your girts below.

Alternatively, for a large shed you could just set a post where each truss will be, notch the top of the post and drop the truss down in that. Then your posts are bearing all the weight and you will only have to worry about the top beam keeping everything straight.

 

[blueriver]

I think the 4x4's are to light I would use at least a 6x6 and sandwich the pole between the two ...

 

[Dave5264]

Third method is to notch out the top of the 6x6 on one side 1.5" deep. Then laminate your 2x's together and place them with one being on the notch. This gives you the doubled up strength, plus the strength of sitting on the notch. Also makes the outer edge 1.5" away from the post so it will line up with your girts below.

.

Thanks for the input

re the idea above, I had considered something similar, with 2 2x6's and 1 2x8 laminated, 2x6's on top of the 4x4 and the 2x8 ontheouter edge as you indicate. I used this method on the horse run-in shed's i built

Blue River - Ill have to re consider using 6x6's for posts instead of 4x4, they will be 6' apart

 

[beppington]

Third method is to notch out the top of the 6x6 on one side 1.5" deep. Then laminate your 2x's together and place them with one being on the notch. This gives you the doubled up strength, plus the strength of sitting on the notch.

This is the exact method a contractor used on the big, tall 40x50 barn I park my tractor in at my parents' place. Just so happens you can see it pretty well in one of my tractor pics. I haven't measured the height, but since my ROPS clears, it must be ~10 feet to the top of the 2x12 beam shown.

 

[Super77Guy]

I'm planning for a small 18'x24' pole barn, and I'm also planning to use 4x4's. I did some research on the load and deflection for the poles, and since I'm only going with 8' high walls, 4x4's will be fine. If you were to go with 10' high walls, then they call for 4x6's to be used. With that said, if you want to go with bigger poles, there's nothing wrong with that either...

 

[LD1]

I agree with the others. Just sandwich the pole.

I typically use a 12"-18" long peice of 2x4 or 2x6 nailed to the post under the header beam as well. If you have a sight level/laser level/transit, you can pot these short peices of board on first (making sure they are the exact same height all the way around so the header will be level). This makes it easer to set the heavier 2x8 or 2x10 header and also helps the strength.

The main problem with trying to attach to the top of the post is, there is no good way to attach it. There is more than just a vertical load to take into account for. There is lateral loads and up-lift from wind gust (especially when doors are opened) to account for as well. And you loose a lot of this setting it on top. And there is just no real good way to attach and make it look good/clean IMO

 

[QRTRHRS]

I agree with LD1 on using short pieces of wood for support and ease of header placement.

I would put plates on both side of the verticle posts. Leave the post a little long to nail the trusses or rafter to for added strength. For the trusses setting in between verticle posts, sandwich a short length of wood to nail the truss to.

I also think pre-drilling the short lengths of support blocking and then screwing them or hand nailing is best. It reduces the tendency for the blocking to crack.