The frost line also called frost depth varies from region to region.
Fence post frost line.
Even if you put the footing down to the frost line frost can still grab the side of the post or footing and push it up.
It seems like frost wouldn t push up a post if it the post extended below the frost line.
C to keep frost from bonding to the sides and jacking up the footing.
Dirt then slips in beneath the concrete.
The process is then repeated next winter raising your fencing a bit further.
When building a fence it s important to think about the frost line which is the deepest point in the ground where water will freeze.
Typically in part to ensure that posts lodge below the frost line experts call for a hole deep enough to submerge the bottom third of the post below ground.
The resulting pressure literally heaves the fence posts out of the ground over time.
Also where frost only penetrates the soil an inch or two there is no need to be concerned about frost heaves such as on the west coast and the southern most parts of the u s.
Frost heave prevention for fence posts.
For a six foot tall post therefore.
Consider the frost line in your area.
The trouble begins when frost starts to heave your concrete upward using the tops of those v shaped concrete footings to grip them since the tops form a lip.
Watch the frost line.
I am not too concerned about concrete providing lateral support for the fence above ground because of the posts depth and 5ft spacing.
However where freezing goes deeply into soil your fence posts and the footings of your deck are subject to this upward pressure.
Despite what some people believe making a long lasting fence is not always as simple as sinking a post in the ground and moving on to the next post.
For example a 6 foot tall fence will need at least 2 feet of post in the ground.
The bottom of the post needs to sit below the frost line consult local codes for exact requirements.
But the frost line may be different depending on the climate you live in.
Frost heave is a condition that happens when water freezes in the soil and then the soil thaws out.
In these cases it s best to surround the post or concrete with a smooth surface of plastic a waxed tube or plastic pipe fig.
Generally a hole that is at least 1 3 the depth of the fence will keep the fence from heaving when the ground freezes.
The best way to prevent frost heave in fence posts is to set them on a drainage bed prior to pouring the concrete.
Your fencing is raised as a result.
