Post Embedment in Clay

[flatbread]

pole barn- 8' spacing

Has anyone ever buried posts in clay
If so, would you like to share the depth


would 3' embedment do the trick (4' would be extremely tough with 4' post hole diggers, for these little pistols) These are 4x4x12

id even love to hear stories of failures from not burying deep enough or even successful stories

 

[nehog]

Where you are located is significant, but you've kept that a secret!

 

[dreamingmuscle]

Where you are located is significant, but you've kept that a secret!

Ditto. Freeze thaw cycles play a big part in foundation depth

 

[RPH]

Use of the post? Light weight fence or beginning of the barn?
Hanging a gate? Location and use will get you a wealth of information fro these fine folks here.

 

[Fyrme]

Use of the post? Light weight fence or beginning of the barn?
Hanging a gate? Location and use will get you a wealth of information fro these fine folks here.

Original post

pole barn- 8' spacing

would 3' embedment do the trick (4' would be extremely tough with 4' post hole diggers, for these little pistols) These are 4x4x12

4x4 is way too small for a pole barn imo. You need at minimum 4x6. I wouldn't go smaller than 5x5 or 6x6. They are the most common around here. As far as depth, we need more info on location and climate.

 

[theoldwizard1]

It is all up to what is your application and what are your local codes.

Back fill with crush gravel <5/8" (do NOT use pea gravel). Backfill in 6-12" lifts and pack well.

 

[noboD]

Use of the post? Light weight fence or beginning of the barn?
Hanging a gate? Location and use will get you a wealth of information fro these fine folks here.

He says it's for a pole barn. If your clay is like clay in this part of the country it never dries out. Concrete is the only way. Your local ordinances should tell you that.

 

[bczygan]

pole barn- 8' spacing

Has anyone ever buried posts in clay
If so, would you like to share the depth


would 3' embedment do the trick (4' would be extremely tough with 4' post hole diggers, for these little pistols) These are 4x4x12

id even love to hear stories of failures from not burying deep enough or even successful stories

You need to rethink. Difficulty of digging the hole with your post hole digger should not be the limiting factor.

 

[RPH]

Seen barns with 4x4 posts. Looks like a roof held up with toothpicks. 4x6 at least and 6x6 in other areas.

 

[79firebird]

Helped a buddy build one a fue years ago not far from me in clay used 6x6's and had to go down 8 feet due to the size of the barn 50x60 14 foot walls. in the last 5 years its sunk about 1/2 a inch.

 

[ms fowler]

I would discount any effect from the length of embedding. Unless you have 20 feet or more in the ground, ( estimate) the load will be end-bearing only. Clay will support a load for a while, but will eventually fail. You need footings below the posts to spread out the load. It could be as simple as a foot or two of compacted crushed stone with fines, but concrete is easier to control, and to know what you've got.. Embedding will help with side/ wind loads, but the weight of the building will be carried on the ends of all the posts. Ask a local foundation/soils Engineer who would be familiar with your local conditions.

 

[flatbread]

@79firebird, what is your frost depth , if you dont mind me asking?

frost depth (6")
clay hard as rock in summer
some people backfill with gravel, some with concrete (heard some bads with both though)

You need to rethink. Difficulty of digging the hole with your post hole digger should not be the limiting factor.
a small gas auger is around 300 here, just wandering if this was doable w/o saving to hire someone with a tractor

 

[flatbread]

@79firebird, what is your frost depth , if you dont mind me asking?

frost depth (6")
clay hard as rock in summer
some people backfill with gravel, some with concrete (heard some bads with both though)

You need to rethink. Difficulty of digging the hole with your post hole digger should not be the limiting factor.

a small gas auger is around 300 here, just wandering if this was doable w/o saving to hire someone with a tractor or bigger pistols

 

[79firebird]

frost depth here i think is like 6 inches. where im at we rarly see it get under -2 for more then a day. used a gas auger with an extension on it the same size at the post so we dident have to backfill it

 

[pmiranda]

Where I'm at, the worry with clay is expansion/contraction from rain/drought. Most people have to water their foundations regardless to keep the house from cracking. Even with watering through winter my driveway has sunk at least an inch on one panel.

 

[Highbeam]

Without worrying about frost depth, your minimum is a 2 foot wide hole 4 feet deep. Concrete cookie below the post to ditribute the load.

 

[5lima30]

Packed gravel is how it is done in our clay/rock type ground. In this area you would go at least 36" deep to avoid the freeze/ thaw cycle. Good luck!