“Pole barn” construction questions

[Russell King]

I am planning on moving an existing structure and adding some shed roofs onto it for a barn/storage/workshop. The existing structure is an odd two story building that is sitting on concrete piers and will be sitting on concrete piers when it is moved. That is because the property is in a zone A 100 year flood plain. I have never built any substantial structure and have a few questions about the additional shed roofs and support.

Here is a picture of what it will generally look like but not nearly so nice. And the lean to sheds will probably be enclosed instead of open. The area underneath this structure will be covered with crushed rock (gravel) not concrete.


Since the existing structure will be on concrete piers that happen to be going 15 feet into the ground due to the poor soil on this property I was talking to the foundation contractor about having him drill the holes for the supports. These supports will be 8 inch diameter gun barrel pilings that can be pressure treated to 0.60 pcf and then coated with a polymer coating.

In my experience any pole barn construction that I was around simply buried the poles into the ground, sometimes concreted sometimes not. Depending on the site conditions those poles would rot out in some amount of time. Some people constructed their pole barns just sitting on concrete piers. But with the pressure treatment and polymer coating on the underground portion that should extend the life of these columns probably past my expiration date of life.

Now for the questions:

Is it better to sink the poles into the ground so they can take shear load or is it okay to just have them attached to concrete piers (that will be seven feet deep due to soil conditions)?

How would you attach the poles to the concrete? Simpson has a PBV (Post Base for Vigas) that look acceptable for this type of structure since the tops of the poles will all be attached together by the top rails and also the girts.

Any other suggestions on how to construct this structure?

Sorry for the long post.

 

[North Idaho Wolfman]

There are a lot of factors that I ask my clients when I build them a building.
I also take into account the area and factors like wind, cold, wet, and what the exact purpose they want to use it for, as those factors all dictate the proper build for the conditions.
I'm a huge fan of monolithic foundations as they really don't give a hoot as to what kind of ground you're putting the building on.
I'm also a huge fan of hydronic heat.

I also don't like poles buried into the ground because no matter what you do they will degrade.

Newer pole bar posts will be glue lam posts and not solid wood posts.

If you want a pole built design then I would go concreate in sonotubes with CB66 or CB88 post bases
or Midwest Perma Colum swp bases

 

[Russell King]

most column bases are for rectangular columns but I want to use round instead. I have found some for timber framed columns and the Simpson ones. I like these but will discuss that with the contractor. I just have to get over thinking they need to carry much in the bending direction.

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Thank you for your input.

 

[MapleLeafFarmer]

different norms if different areas for sure.

we get frost down to 7+ feet so we sink our post for poll barns down to 8+ feet.

This is what the top shelf commercial builders here are doing.

Poles normally ply constructed with 2X8's, 5 ply nailed and glued very common, portion in contact with ground is PWF, and above ground portion not PWF, holes are back filled with clean stone for drainage and about 6" of stone at bottom of hole for post to sit on, no concrete footing at bottom of hole, spaced 4' apart.

We are in an area that is very well drained (sandy soil type) and no termites.

 

[Mark_BX25D]

most column bases are for rectangular columns but I want to use round instead.

Why round? They are a royal pain any time you want to attach something.

 

[Russell King]

Why round? They are a royal pain any time you want to attach something.

I like the aesthetics of the round columns and they are technically better than rectanglular column. If you bump into them you generally won’t knock a corner off.

 

[North Idaho Wolfman]

Round poles for a pole barn are pretty cost prohibitive as the construction costs should be off the scale.
I would think your contractor would steer you away from that building material real quick!

 

[Russell King]

I am the contractor (so far) and the round material costs are reasonable (over a phone quote). I will get a quote for both 8 inch round and 6x8 rectangular. Both will be pressure treated even though they probably don’t really need to be if mounted on concrete piers. That is because the property is in a riparian uplands and wood seems to rot relatively quickly in the area, even painted and no ground contact.

Why would the construction costs be any greater? The girts are nailed at the surface contact area regardless if the column is square or round. I can understand that where two girts end at the centerline of one column could cause some problems with attachment.

I really appreciate the feedback since I really don’t have much construction experience. I am not trying to be argumentative about it but am just ignorant about what problems I might be causing. I do know that some people have used telephone poles with a taper to build barns with but these columns will be the same diameter top to bottom. I understand that the taper would cause difficulties and probably have to be shimmed out as the diameter changes.

 

[North Idaho Wolfman]

In my 40+ years of building I've worked on quite a few round post and beam houses.
They are an pain in the backside trying to make flat square material attach and finish to the rounds is difficult to say the least.
You end up spending more time cutting, notching and fitting to the rounds then you do squares or rectangles.
Another issue is there is a small point of contact when you attach flats to rounds, which create weak points.
If your going to do rounds plan on using a lot of timber screws to attach all of the structure to the posts.
Nails are worthless.
The post bases you show, provide for very little support.


I had one client that insisted on using a pile of telephone poles to build a barn.
It worked but in my estimation it took us twice as long to build, and didn't make that nice of a pole barn.

Layout of the post bases it very critical use forms to line and space the bases because if the bases are off the posts are off.
A post off 1/4" may not seem like much, but when finishing it will bad.

One another note:
If you need to get Plans, Permits and inspections, prepare for a battle.
As you are building what they consider non conventional and if they require grading on materials just the post bases you listed do not pass and getting graded rounds is near to impossible.

If you don't need plans permits and inspections the world is your oyster and then do what makes you happy.