What type foundation for wet ground in Alaska

[chugiaklt2]

I have some property in Talkeetna AK and the ground is wet year round.  While clearing the land last year with an excavator I dug down to find solid ground and ran out of reach with the excavator before I found any (13 ft ).  I am curious what type of foundation to use, the land is remote and hard to get equipment into.  My little brother works for a company that drives 4" piles and they can get to the land but even with the little brother discount it is still going to be $7000 for 12 piles!!!  They also won't come for less then 12 piles.  I do not want to spend that kind of money for this part of the project.  We are looking to build 24x32 with a loft.  Any suggestions on foudation types would be greatly appreciated.

Thanks
Chris

[bayview]

   I doubt if 12 pilings would be enough for the size home you want.   I wonder how much weight a 4" piling carries.   You do need to get the pilings to solid rock for a firm foundation or risk movement.   Expect to spend some $$$.

   We have expanding clay in my neighborhood of Texas. . .    The soil can expand, contract vertically up to 12".   A proper concrete pier and beam foundation for an average home costs $40-50,000.   Foundation repair is big business here.


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[kenhill]

everyone will recommend not to skimp on foundation.  A 24 x 32 Cabin is a chunk of investment.  Once on a foundation, it is costly to go back and fix a cheap foundation.

There also is a contractor in the area that has an augger type foundation that screws down into the ground.  He will go down 40+feet.  You get the pipe in there via ATV or snowmachine.  Not sure if he can augger in the winter.  I called an talked to him, but my ground at Red Shirt Lake was good gravel soil, so I did not need his system.  It is good for your type of soil.  There are several homes on Red Shirt built in wet areas that are now all heaved and leaning.  Don't skimp!

[rwanders]

On good ground in Willow, 23 miles south of Talkeetna, I needed 16 12" sonotubes with bigfoot footings at 48" depth for a 24x34 with a loft----as noted above, do not skimp on foundation. Best to consult a soils or structural engineer for specific advice. A different location may be advisable.

[lonelytree]

Chris - Is your lot on permafrost? Do you have clay? Is it possible to use french drains to dry it up or is it true muck? If muck, does it have a bottom? 4" tubes are $700 each near Glennallen. AAA Fence puts them in. The expense of getting the machinery in is most of the cost. Do you stil have the excavator out there? If you have a welder you can drive them with it. Used metal is around. I heard that there are several miles of pipe in Seward for cheap, but have not talked to the guy for a while.

That is a pretty huge house. I am 20X32, dual loft, up and dried in. Yell if you want to have coffee.

Mike

[John Raabe]

You're getting some good advice here from folks with local experience. I can't add to that except to say that when building in wet sloppy soil there are really only two strategies:
• Get piers (driven or poured) down into something solid
• Build a heavy structural slab solid enough to "float" and ride out expansions and settlements
• Best - do both!

[DirtyLittleSecret]

I was just going to ask whether itd be possible to build a "sled foundation" to float or ride out seasonal changes.  Ive spent ALOT of time in Talkeetna area (have climbed Denali numerous times as well), and there are true sludge pits out there...

[chugiaklt2]

Thanks for all the replies so far.  I would like to add a picture so you can see the type of soil I am talking about, I may have better soil then I think.  Can somebody tell me how to post pictures?  Thanks

[MountainDon]

Images need to be uploaded to an image host service like photobucket.com. That's the one I use, there are others. Once the image is on the host site the "image tag" is copied and pasted into the forum message at the point the image is to appear.  The image tag begins with [IMG].....


Give a holler of you have trouble. There is a tutorial under the Forum News section but it is a little out of date.

[eddiescabin]

<<<not an expert on this type of thing but Mr Raabe's advise (think THICK slab and heavy/much rebar or even  layered chain link fence embedded in the concrete) seems like the best option.  I think you are going too big for a skid mounted structure.  Maybe look into what they do in sand areas?  Good Luck

[lonelytree]

I really doubt that concrete is an option.

What looks HUGE as a foundation begins to look small when you put a house on it.

Can you mine gravel from a ridge/hill/creekbed to put in as fill for the house site? Then compact and crib on top of it?

I have a friend northwest of Glennallen. He hauled in 6" I beams for the beams AND to drive into the ground. He had some hit hardpan at 10 feet and some took 3 sticks. Since there was such a variance he put custom adjusters between the posts and beams. Now he can level his cabin in less than a couple hours with a water level.

[rwanders]

As you consider all your options for foundations-----if they all seem dubious, don't forget the other option----find another property. It may seem expensive but, if you could use a simpler design you may actually come out ahead. Also, if your whole site is really that wet it may also make an access road, septic systems and even outhouses difficult to build and maintain. Bad ground is the gift that never seems to stop giving you aggravation and picking your pocket. If the property's other charms override all these problems. Well, good luck to you and keep us posted.

[chugiaklt2]

I will try posting the pictures when I get home in the morning can't use photobucket at work.  I do have the ability to bring in some gravel to the site.  I already have a established unmaintained dirt road to the property that has been in place for about 20 years.  We put in an outhouse last summer and have not had any problems with it I will post a picture of that also. 

What is the best way to find out what the frost line is?  Last year when I was clearing land with the excavator I dug up big lenticular ice sheets about 1 to 2 feet below the surface.  I cleared about 3/4 of an acre for the building site and there was only 3 of those ice sheets, but they were about 12'x12' and 1' thick.

[chugiaklt2]

Here are a few pictures to help better understand the ground and the outhouse shots are just extra.

Ice Chunk from about 2 feet below the surface

After weekend of clearing

Test Hole dug to about 13' filled up with about 6 feet of water

Outhouse Hole

Outhouse Slab

Finished House

[lonelytree]

http://web.me.com/ffky/Site/Permafrost_Blog/Entries/2009/2/6_Japanese_Delicacies_2_files/Alaska%20Permafrost%20Map%20Dec2008.pdf (see if that is the link you want. JR)

Per the map, you are in sporatic or discontinious permafrost. After removing the trees, the ground cover etc.... you may now have a huge chance of a soupy mess. If that gray layer is clay like I believe, it will cause a lot of heaving. There is a lot near Glennallen that a guy dozed the entire 5 acres. It is still a soupy mess after 2 years and he cannot sell it. The good thing is that you have trail access. Can a cement truck get to your lot?

Anchorage frost line is around 8 feet. Yours will probably be deeper. Go talk to Doug at Moores Hardware or catch Larry at L&N Ventures. Larry has a gravel pit too. Mile 2 on the cutoff.

The first part is tough, the second part is ok, then you are warm and dry to finish it at your leisure.

If you are not truely sold on your final plans. I saw a cabin that is much smaller than mine that makes me regret building such a big place. It is fantastic! I will try to get pictures, but he is hard to find. He is truely remote. Custom post and beam with brackets cut with fish, moose and bou in them. Custom doors that will make you envious. Hand made hinges with antique handles. The layout is awesome and it will be a show piece when done.

Mike

[chugiaklt2]

We are not 100 % sold on our plans.  If the operator is willing to drive on a unmaintained road and drive across a creek then yes it is accessible to a cement truck.  I have not found anybody willing to drive any thing across the creek with a piece of equipment.  I have towed a 15000 lb excavator in with my truck no problem. 

Thanks for the information about Moores and the gravel guy.  I know where each of them are at.

A little more information on the land location.  To get there you turn left prior to the Montana Creek Bridge and go back about 11 or 13 miles from there.  The address is 42277 S MOOSE TRACK LN  if anybody wanted to google map it.

Thanks for the replies

[lonelytree]

I have a friend within a mile or so of your lot. He built on piers wrapped in visqueen. The land is prone to earthquakes, so take that into account. He had one when he first got his cabin up and I guess it made him pucker. Remember that the land can change in just a few feet. Do you know any engineers that could assist you in making an informed choice?

I just figured out your outhouse design. Did you run any leach lines or just a holding tank? A friend bought his place near Lake Louise. The septic tank was over full. It took several months of pumping the melted stuff off to get is down to half. He even put a heat lamp in it. I am still working on a design for mine. The engineer at DEC has sent me some information and is very helpful. You can also take a class to get certified.

Did you get your Mat-Su land use permit? If not, they can put a stop on you. If you stay under 480 SQ FT, you can do what you want and they keep out of your business. The taxes are lower too.
Mike

[chugiaklt2]

The outhouse has a 300 gallon holding tank that has some drainage for liquids.  We have been using it since 4th of July and there is no smell inside at all.  We use a product called Bokashi to keep the smell down, we sprinke a small dixie cup full down the hole everytime someone goes. It is also vented out the back side of the outhouse with a 4 inch piece of black pipe that extends above the roof line.  The cabin will be used for a couple days a month so I think this will last for a few years.