# How deep to put 6x6 post for small cabin?



## RingsRiverFarm (Feb 17, 2015)

Hey ladies and gentlemen, I am in the process of building a small cabin (20'x30'). We are building this cabin on land that has been in family for several years. The land is all bottom land and we are building on one of the highest spots. The land runs along the Saline River which gets out of its banks once a year, around April. How deep should by 6"x6" post be buried in the ground? I am wanting to pour a concrete base in each hole, maybe 5" deep. Then the cabin itself will be 6 feet high. *Thanks in advance* (This is my first post with many more to come.)


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## werb2008 (Feb 5, 2015)

That's a tuff question to answer,what are the frost levels in the area,and do you have building codes.It would probably be easy digging along the river so I would go as high up as I could and down at least 4 ft. I live in NE PA and in 2011 the river took a lot of cabins that were untouched for decades,Now if you rebuild you have to be above the established flood mark.Good luck and welcome to the site.


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## RingsRiverFarm (Feb 17, 2015)

werb2008 said:


> That's a tuff question to answer,what are the frost levels in the area,and do you have building codes.It would probably be easy digging along the river so I would go as high up as I could and down at least 4 ft. I live in NE PA and in 2011 the river took a lot of cabins that were untouched for decades,Now if you rebuild you have to be above the established flood mark.Good luck and welcome to the site.


Not 100% on the frost levels, I live in central Arkansas. No building codes where I am. I was thinking 6 feet down but want to get other opinions. Thanks for the warm welcome.


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## mreynolds (Jan 1, 2015)

I have built near the coast and they require 16' above sea level and 8' (12' recommended) in the ground minimum. Most think this is for hurricanes but it is for storm surges instead. Hurricane Ike had a 22' storm surge and wiped out all but one house that was above standard and just built. My advice is don't underestimate the power of moving water. Especially a flooded river. 

I used to survey way back in the day and we did a job for a GC on an apt complex. He wanted the slabs exactly 1" above flood plane so we did. The problem is that once more slabs are put down less ground area to absorb water. (including parking lots) We had a massive year for building that year and 5 years later we had another flood. That apt. was washed down the river. Both floors. 

Go big and better now and don't look back. :thumb:

Just my nickel
Mike


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## mreynolds (Jan 1, 2015)

oh and 8' should be well under the frost line for Ark.


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## RingsRiverFarm (Feb 17, 2015)

Thanks mreynolds for your 5 cents  much appreciated!


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## RonM (Jan 6, 2008)

3 ft below ground around here for posts is plenty, sitting on concrete


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## mreynolds (Jan 1, 2015)

RingsRiverFarm said:


> Thanks mreynolds for your 5 cents  much appreciated!


NP river. Its just that the difference in a few feet longer post will not cost much and when the river does rise you will have peace of mind and not _piece_ of mind from dear spouse instead.


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## wy_white_wolf (Oct 14, 2004)

Frost level for a minimum depth. Then you need to figure side loading from forces such as wind. That will depend on the wind loads for your area, type of soil, and size of structure. Usually about 1/2 the hieght of the post works out to cover all bases. So 6' high would be 3' down.

WWW


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## chromdome35 (Apr 12, 2013)

How many posts are you going to use and what kind of soil they will be buried in?


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## michael ark (Dec 11, 2013)

Around here in this part of arkansas by code you have to go at least 2 ft down with water and electric to be below frost lines.


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## Nevada (Sep 9, 2004)

michael ark said:


> Around here in this part of arkansas by code you have to go at least 2 ft down with water and electric to be below frost lines.


Two feet should more than do it for Arkansas. Looks like most of the state is about 10 inches. Use this diagram as a guide for frost depth.


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## RingsRiverFarm (Feb 17, 2015)

chromdome35 said:


> How many posts are you going to use and what kind of soil they will be buried in?


There will be 3 rows of 5 post. The soil is a hard compact clay type.


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## Guest (Feb 21, 2015)

RingsRiverFarm said:


> There will be 3 rows of 5 post. The soil is a hard compact clay type.


Frost heave will be your biggest concern. I would suggest footings below frost level under posts,,,something like sonotube footing base or similar, even square 2'x2' x 8" square homemade form, securing the posts to the footing.


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## dltasig7 (Feb 5, 2015)

If you went down a total of 6', poured a 2' thick concrete footer, placed your 6"x6" post onto that, and then poured concrete around the posts to fill up to the top of the rest of the hole, you should be fine. I've poured footers and set deck, fence and addition posts in Buffalo, Rochester, and Redwood, NY and never had a problem if I started at or below 54"


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## vpapai (Nov 18, 2010)

What precautions would be needed for the clay soil that the poster has? I am thinking of placing posts as well, have orange clay a foot down that goes quite deep.


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## dltasig7 (Feb 5, 2015)

I'm not sure that's a concern if you are deep enough. When it come to digging (especially if you have or are renting equipment) just go deeper...Why not?


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## volleypc (Jul 25, 2010)

Frost heave will not be your biggest concern. If you are wanting the bottom elevation to be 6ft off the ground then your post will be well below the depth of the frost level to keep the post from overturning. Is it a one story or two story building? Do you have to go 6ft high?


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## Jolly (Jan 8, 2004)

This is only a 600 sq ft cabin...3 feet of post in the ground, sitting on concrete, should be enough. Make sure you brace the corner posts.

Alternatively, go 3 feet in the ground, run your posts up a bit higher than 6' and nail the wall structure in the corner posts.


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## just_sawing (Jan 15, 2006)

I have sawed hundreds of post and patterns for a cabins. My rule is if your going to live in it post in the ground is not the best idea. Yes it is done all the time but for longevity digging a post hole and pouring concrete is better. Your post have a determined life span. and when they are deteriorated your cabin is now a chicken coop. Also with a livable cabin the psi on the post is normally greater and therefore there will be some sag. The problem with sag is it is never even. A pillar type build is better for termite barriers also. The other which doesn't appear to bother you is that the local mills like to stay under 16 feet. It is very easy to run out of pole before you run out of your dream. 
Like I say I am not knocking pole barn construction at all and for a hunting type building go for it.


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## Jolly (Jan 8, 2004)

Another thought....if you can get a concrete truck in there during the summer, what about Sonotubes?

As has been said, pour the whole thing.


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## texican (Oct 4, 2003)

What JustSawing said about not sinking posts in the ground, even if pressure treated.

I live alongside the Sabine flood plain.... mile and a half to the river, normally.... when it floods, like it did here (mildly) just last week, the river in flood gets within 100 yards of my house. But it's still min. 13' above the highest recorded water. Asked my grandpa that owned this land forever, the highest he ever had seen it (epic floods in the '50s), and he was pretty much on the mark.

I'd first off, NOT build, anyplace you know already gets underwater. If you do, I'd not sink my concrete pole footers only 5" deep... Might go 5 'feet' deep, and at least 12" 'tube'... with rebar in it. Then use metal fasteners to connect your posts to your cement pilings... Six feet high? Sure that's high enough? If you make a mistake, it'd be difficult to raise it later.

IF I did build in a flood zone like that, I'd make sure to leave quite a few trees around the cabin, to keep floating logs from drifting up to the house, getting stuck on the posts, building up debris.... the water will flow through and not put much pressure on the structure.... let a few logs lay up against it, with water moving, and you've got tremendous forces at work.... I'd say a catastrophic failure.... however, if the surrounding trees catch the drifting logs......


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