Simple Question...

[Ram07]

When you build a fence, whatever...a foundation perhaps, you did deeper than the frost line....how deep do you dig?

I have a reason for asking, I'm not a dummy....although, I have to put up with some...please reply...

[Ram07]

Well, to give you a hint...have a buddy with frozen waterlines to his house (actually his whole street....which was just redone, last summer), he was told by this fine City's Engineer, that this years frost line is 12 feet deep...so his woes, are just an act of god...so to speak...
 

[moparsr2fast]

  A fence, or a deck footing etc... is 36" here in the states

[Ram07]

I live where is cold, 3ft min, most do 4 ft..

[Ram07]

be a hell of a basement to dig, huh....12 ft...

[Mopar Nut]

3 feet

[polywideblock]

only frost line I have is in the freezer       no help I know but just sayin   

[moparsr2fast]

be a hell of a basement to dig, huh....12 ft...

  Even more so if it was frozen the whole way..

[oldgold69]

here in the frozen tundra     a garage footing  is 4ft 8 in to the bottom  we usually dig fence posts 4 ft  but I put a piece of Styrofoam in the bottom of the hole this keeps the frost from pushing on the post columns  but we have frost over 5 ft deep where there in no snow  but if the snow is over 2 ft and undisturbed their is no frost in the ground you can stick a shovel right in

[oldcarnut]

I guess this may sound like a stupid question but what's a frost line and why does it matter  ?  I can assume what the frost line is but why does it matter for a fence post?  I've only seen here on the SE coast about a 2ft hole filled with concrete for a fence post.

[Mytur Binsdirti]

12' frost line; where are you, Alaska?

[hawkeye]

North Missouri, 3 foot under sod, 4 foot under roads, sidewalks or driveways.  If you don't get a post below the frost line it will keep "heaving" upward.

[Ram07]

Yes, the standard here is 36-48 inches, thought that was the case with, well...everywhere...Seems the city didn't quite did deep enough, and a water main broke...a entire street lost their water, not to mention a huge watery mess, the quickly turned to ice.

The City Engineer had a very fine, but somewhat confusing explanation for it...long story short...he said the frost line is 12 ft deep this here...not his fault...

[draftingmonkey]

I guess this may sound like a stupid question but what's a frost line and why does it matter?  I can assume what the frost line is but why does it matter for a fence post?

The frost line—also known as frost depth or freezing depth—is most commonly the depth to which the groundwater in soil is expected to freeze. Building codes sometimes take frost depth into account because of frost heaving which can damage buildings by moving their foundations. Foundations are normally built below the frost depth for this reason.
The same can be said for fence posts. Depending on type of construction, a moving post & foundation can cause a fence to be pulled apart.
Attached are some diagrams of fence post construction and average and extreme frost line maps. Typically the average is used for most construction due to cost.
Ram07-to ere on the side of caution I would probably use the 48" depth.

[HeavyFuel]

Fixed!