How Can We Mitigate Our Exposure to Building on Clay Soils???

[kyfarm]

Hi Everyone,

I'm relatively new to this site.  I have been lurking for awhile, admiring all the beautiful projects ...     ...   We are currently in the planning stages for a home that we hope to start building in the spring.  We are seriously considering the plans for the 20x30 1.5 story cottage.

Our first challenge is going to be the foundation  ...  The only suitable building site consists of silty clay.  I don't know how expansive this soil is but since this will be my family's only residence, I do know we need to take every precaution to ensure that we mitigate the possibility of settling, buckling, etc ... 

If we were to build the 20x30 1.5 story on this site, what is the best and/or cheapest way to mitigate our exposure to expansive soils?   


Many Thanks In Advance For All Your Help!!!!

[rwanders]

Best plan is to consult with a structural or soils engineer who can test your site and advise on engineering needed----a relatively small investment that may prevent some expensive mis-steps in design. An inadequate foundation can cause almost endless problems as you build or as the years go by.

[Don_P]

Clays come in many flavors. The first person I'd ask would be the county building inspector to see if it is a problem locally.

[poppy]

  to the forum.  Lots of help here.

Almost any type of foundation can be made to work in clay.  It's a function of site conditions, design, cost, and drainage or lack thereof.

Give us some more info. like what general location in KY, and where the frost line is.

A pier foundation would be the least costly, expecially if the site is fairly flat.

First, as Don_P suggested, find out exactly what type of clay you have and what kind of drainage there is.

We need more info. in order to suggest depth and size of pier bases.  There are several ways to avoid frost jacking.

[johnky]

check out http://www.bigfootsystems.com/index.php they make bell footing forms, and they have small ones for sheds and cabins.  They also have load tables and instructions and you can even call them if you need help.  These bell footings are made specifically for the soil you describe.

There's also some good info on bell footings at http://www.shedsusa.com/products/SonoforKitSheds.pdf

Good luck!

[kyfarm]

Thanks Poppy!

Oh ...  sorry, I should have provided a little more information ...   

Our farm is in Breckenridge County, roughly 30 miles west of Fort Knox  ...  Our building site sits on top of a small ridge ...  It is fairly level ... 

Regarding Frost depth:  Building codes in some surrounding counties state that the frost line is 2 feet.  My county does not have any building codes however ...

[kyfarm]

Regarding drainage, the soils information that I have access to (http://websoilsurvey.nrcs.usda.gov) states that the building site is well drained ...  water table is low (depth of at least 80") ...

Thanks Again.

[johnky]

Hi kyfarm,  I'm also getting ready to build in Kentucky - southeast ky

There is a Kentucky Building Code and it is statewide.  It is up to the cities and counties to enact ordinances that implement the permitting, inspections, fees, etc. and hire inspectors, and a lot of counties never did it, so you can basically build without any fees or inspections, but technically you must build according to the code unless you are a farm or farm dwelling and I believe you have to have at least 10 acres to be considered a real farm.  Where I'm building there is no permitting or inspections, and I qualify as a farm so I'm exempt, but I'm still trying to stay within code as much as possible.

You can find the Kentucky Building Code at:
http://dhbc.ky.gov/NR/rdonlyres/3553C864-232E-4CA9-A3EE-4A0A58C15E59/0/2007KBC4thPrintingMarch2010.pdf

The KBC is basically a short 86 page document that makes some minor changes to the 2006 International Building Code and the 2006 IBC is the underlying code that we are supposed to adhere to.

Your county, Breckenridge, is listed in the KY code on page 66 as having a frost level of 24 inches.  You should definitely get your footings below the frost level and have some gravel in the bottom for drainage too.  There was another thread posted just this evening from the owner of this forum about doing your own soil test.  check out http://countryplans.com/smf/index.php?topic=10043.msg128487#msg128487

[bayview]

   Ask your neighbors . . .    What kind of foundations are they using?

   Have the soil checked . . .

   If you have an expansive clay soil . . .    You would want to build with a pier and beam foundation to bedrock.   Or, have the soil stabilized.

   The foundation is not a place to cut expenses.

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