What is the frost line for Kentucky?

I am goign to build a pole barn. I need to extend the posts 6 inches
below the frost line. How do I find out what the frost line is for my
area?
Reply to
stryped
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Your local county extension office should be able to tell you what the projected frost line is in your area, or perhaps a local contractor.
Frost line here in Alabama is the grass line! My water line from the main is only 6 to 8 inches deep......
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Reply to
~Roy~
This Kentucky source indicates a frost line of 30", but you would still be best asking the local practices from the local building inspector, as frost lines can vary. The frost line is more or less arbitary, but is intended to cover most years. In a really cold year the frost can go lower and freeze pipes.
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Richard
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Reply to
Richard Ferguson
I used to live in Kansas. Same latittude, frost line was three feet for water lines.
If you think a severe thunderstrom might happen sometime in the life of the barn, I'd go deeper than that. Poles hold your barn from blowing away.
Karl
Reply to
Karl Townsend
Even if they are concreted? The problem I am having is I will have to do all this myself and it is hard to handle a big pole. I was hoping to use a 4x6 2 feet in the ground and concreteing all holes.
Reply to
stryped
stryped, this discussion has been going on for weeks, and you've still not gotten the point --
The barn won't tend to simply shear horizontally in a strong wind. Rather, it will shear diagonally, torquing all the poles at the point where they enter the soil. If the poles are sized to take the expected wind-shear, then the limiting factor determining whether or not they "undig" themselves from the ground is how deep they are planted.
Do this: Get a strong, sound 2x4, and plant it like a pole two feet deep. Do another one four inches deep.
Now, hold the top of each pole steady upright while you try to push the bottom of the pole horizontally. Can't, can you? That's the action you seem to think the wind will have. No.
Now pull on the top of the pole horizontally. You'll probably break the two foot deep one; You'll easily tip the 4-incher right out of the soil.
THAT is the action wind will have on your barn.
Concrete collars around the poles will only provide resistance to that kind of force if they are as deep as recommended for the pole. Collars are more designed for straight-line lateral forces.
LLoyd
Reply to
Lloyd E. Sponenburgh
I agree with almost every thing you said except the part about the collars. In a former life I did the engineering for a factory built house company. Lots of our sales were for vacation homes built on piles. The best information on piles or poles I found in a pamphlet put out by the Outdoor Advertising Association. Billboards get lots of wind loads.
They recommended concrete collars around the upper third of the pole. The reason was to increase the effective diameter of the pole. The soil at the bottom of the pole has a lot of weight above it, and will resist the pole moving. At the top of the pole the earth does not resist moving as well. So a concrete collar increases the diameter and makes the pole more ridgid.
Don't believe me. Bury that two by four end about two feet deep. Now rock the top back and forth. The bottom of the two by four harly moves, but the ground around the top does.
Dan
Lloyd E. Sp> Concrete collars around the poles will only provide resistance to that kind
Reply to
dcaster
So, what are you saying? Two feet is not deep enough?
The lumber store told me it was ok at that depth if using concrete.
I am sorry but I think a 4 foot hole is overkill.
Reply to
stryped
Man that would be sweet - where I live it's 7.5 feet. We don't get hurricanes here though :)
Laurie Forbes
Reply to
Laurie Forbes
Its a free country, do what you want. Just remember the story of the three pigs when you house blows down.
Karl
Reply to
Karl Townsend
I think that 2 feet is not enough. I would go for at least three feet and depending on how big your barn is I would use bigger poles too. It is not all that hard to put the poles in the holes. Just dig out to the side of the hole a shallow trench about six inches deep and maybe three feet long. Roll the pole so the end in over the hole and the pole is in line with the trench. Lift on the top end and walk toward the hole.
For telephone poles put a two by six in the hole for the end of the pole to rest against and use a couple of come-a-longs so that the pole will not pivot sideways.
Dan
Reply to
dcaster
No, I do believe you. The recent discussion has been more about "pads" as collars than about going down a substantial distance. You're 100% right. But, if you will, comment about the value of just a 6"-10" thick pad at the very top of a pole's earth contact.
LLoyd
Reply to
Lloyd E. Sponenburgh
Building codes in Lexington require 18" W footers 42" below grade thus a total of 42" depth by 18" wide. That means that using an 18" wide footer and the bottom is at 42" from the top of your finished elevation you will meet the building code. This is determined by the frost line and as previous people have indicated that is around 30" here in Kentucky. If you are building a pole barn I'd rent a two man auger, sink my holes 48", stand my poles plumb and fill with concrete to the top. Obviously you will have previously determined the wind direction and positioned the barn so that the least amount of eave under hang is getting the most general amount of wind.
Having built my share of pole sheds in windy N Texas I can tell you that if you have a roof with an open area that will catch the wind it WILL catch the wind and become a huge sail. Sinking the poles just in earth is OK but with the termites here in KY the concrete gives you that much extra protection from those nasty creatures.
Pedroman
Reply to
Pedro
I am thinking 24x32.
By the way guys, the local ag center says the frost line is 24 inches.
Reply to
stryped
What do you mean "stand my holes plumb"?
Reply to
stryped
When you install the holes into the ground, make sure you don't set 'em in crooked.
Reply to
Dave Hinz
Surprised to see this thread still going. You need a system to resist horizontal loads. If the poles are not deeply embedded then you will need a system of diagonal braces in every plane (including the roof plane(s)). Even with diagonal bracing to resist horizontal loads, you will still need a system to resist uplift. This will usually be concrete footings for the posts. The amount of concrete needed depends on the weight of the building and the roof area supported by each pole. In high wind areas in NZ (55 M/s) the requirement is to design for a uplift of 100Kg/sqr. metre. If the poles are to resist horizontal loads without diagonal bracing then they are working as cantilevered piles and the theoretical resistance to movement at the top of the pole goes up as the square of the depth of embeddment. Deeper is much better. My guess is that 3 or 4 feet of embedment with a concrete collar around the top third of the pole would be about right. Don't underestimate wind loadings, wind loading goes up exponentially with wind speed. One useful trick is to set a small concrete culvert vrtically in the post hole, pack earth and rubble around this to hold it in place and then you have room to manuever heavy posts into exact alignment without crud dropping into the post hole as you do so. When you have the post properly positioned inside the culvert, wedge it in place and and fill the culvert with concrete. Hey presto!.
Reply to
Roger_Nickel
Depends on the area, I find that concrete rots out poles faster. Also. I have a pole shed with all open areas, no walls at all. It's sheltered so the wind doesn't take the roof off.
Reply to
Nick Hull
It doesn't matter whay you think, it only matters what the wind thinks. You will never know if you put the poles too deep, but you will find out if you put them in too shallow.
Reply to
Nick Hull
Well it would be better than nothing. 10 inches would be about right for a pole that was only set in about 2 1/2 feet. If I were only going to put in six inches of concrete, I would put it in about four to six inches below the surface.
Depending on what the soil is like, using cement mixed with the soil is another option. Often a lot easier to do than using concrete in areas where one can't get a truck close to the site.
Dan
Lloyd E. Sp>
Reply to
dcaster

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