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Thread: Cribbing for 16x24 cabin

  1. #1
    Member AKtrpr's Avatar
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    Default Cribbing for 16x24 cabin

    I have a general idea, but figured I'd ask for some input on cribbing for a 16x24 cabin.
    1. Do I need to use rail ties?
    2. How high should my cribbing be?
    3. Is 24" lengths enough and should they be spiked together?
    4. Or can I use the rail ties on the bottom and regular or treated timbers until I reach the desired height?

    cabin location is in nenana and according to my neighbor he says permafrost is 2' down

    thanks in advance to all replies

  2. #2

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    Quote Originally Posted by AKtrpr View Post
    I have a general idea, but figured I'd ask for some input on cribbing for a 16x24 cabin.
    1. Do I need to use rail ties?
    2. How high should my cribbing be?
    3. Is 24" lengths enough and should they be spiked together?
    4. Or can I use the rail ties on the bottom and regular or treated timbers until I reach the desired height?



    cabin location is in nenana and according to my neighbor he says permafrost is 2' down

    thanks in advance to all replies
    No, you don't need to use ties, just treated timbers would do fine, but railroad ties are usually cheaper and that's why people use them.

    I believe it is recommended to make your cribbing at least 36 inches high to get proper airflow under the structure to prevent melting of the permafrost.

    Not sure about your length question. I am curious what other people will say to your question on this because I have wondered the same thing. I am planning on cutting my railroad ties into 32 inch lengths, because they are 96 inches long so you can cut them into thirds at 32 inches. 24 inches might be a tad bit small, but maybe not.

  3. #3
    Member ChugiakTinkerer's Avatar
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    My experience with cribbing is limited to underground coal mines. Your question on length is a good one, and there probably is no correct answer. Keep in mind that the longer the piece, the more area you have supporting your structure. I think the timbers should be at least as long as the cribbing is high. Actually that probably is the correct answer, because now that I typed it I seem to recall reading that somewhere in my recent reading on cabin foundations. Spiking them together couldn't hurt, and might mean the difference between an intact cabin and one that falls off it's supports due to wind, etc.

    Edit to add: I agree with Jack that 36" seems like a good height. The Cold Climate Housing Research Center has a publication on foundations in permafrost, available here. It says a minimum of 24" to ensure adequate air flow to keep the ground below as cold as possible. Higher is better, when it comes to permafrost. And 24" doesn't give you much room to get underneath the structure, which you will need to do at some point.

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    Member DRIFTER_016's Avatar
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    I would spike them together and also spike the cabin to them.
    Alaska is an earthquake zone and it would suck to have the cabin slide off the cribbing in a quake or one of your 100MPH+ wind storms.
    36" does seem to be a decent height to me.

  5. #5
    Member bobmikk's Avatar
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    Seems like a lot of great and very critical questions being asked here... while I am not building a cabin I like to dig around for information on these types of projects and found this excellent reference for cabin building in AK. Seems like it covers that options for footings and other key aspects for cabin construction quite well. Take a look...

    https://www.ahfc.us/files/5613/5716/...n_logmanlo.pdf

  6. #6

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    Chugiaktinkerer and Drifter make some good points about the wind and earthquakes and such. However, seeing as you are building on permafrost, you might have to jack up the cabin later on due to settling and heaving. So if it were me, I don't think I would spike the subfloor to your cribbing. Maybe another option would be to use some heavy duty timberlok screws or something else that is removable. Spikes are pretty much a permanent thing.

  7. #7
    Member DRIFTER_016's Avatar
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    Quote Originally Posted by Bushwhack Jack View Post
    Chugiaktinkerer and Drifter make some good points about the wind and earthquakes and such. However, seeing as you are building on permafrost, you might have to jack up the cabin later on due to settling and heaving. So if it were me, I don't think I would spike the subfloor to your cribbing. Maybe another option would be to use some heavy duty timberlok screws or something else that is removable. Spikes are pretty much a permanent thing.
    You could use angle brackets to attach floor beam to crib and if needed un-screw in order to jack and shim before re-securing.
    Not really a fan of having cabins supported on a 1" piece of all thread.

  8. #8

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    Quote Originally Posted by DRIFTER_016 View Post
    You could use angle brackets to attach floor beam to crib and if needed un-screw in order to jack and shim before re-securing.
    Not really a fan of having cabins supported on a 1" piece of all thread.
    +1 what he said. Sounds like a great idea. It would probably give great shear support but at the same time allow the ability to adjust for settling.

  9. #9
    Member AKtrpr's Avatar
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    Thanks for ok the replies and ideas

    onr thin I can say is not to worry I didn't plan on using the 1" all thread on my beams

  10. #10

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    Here is how I did mine. No complaints after a couple years. A couple of the cribs stacks settled some and I just jacked up the whole crib stack and put some gravel under it.
    http://forums.outdoorsdirectory.com/...cribbing+cabin

  11. #11
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    I used RR ties. Dig down to solid ground to make your 36"x36" pads. Level, compact and put two layers of treated 2x12, one layer crossing the other. Then crib up to where you are level or desired height to run your beams. If I remember, with the length of RR ties, you can get 3ea 34" pieces out of one GOOD tie.No need to tie anything together unless it gives you a piece of mind. You wil have tremendous weight from the stucture. Been 12 years and my 24x24 log place hasn't moved an inch. Also, you WILL want to skirt your place no matter of perma frost. my place is built right on the land of permafrost and the best thing of the foundation that I have done is skirt. Saved LOTS of heat and gave lot of protected and secured storage. Don't over think..

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