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Thread: Cabin Foundation

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    Default Cabin Foundation

    Were moving to Alaska next May. Bought 5 acres in the hills 30 miles north of
    Fairbanks(Hay stack mt.). Thinking there will be plenty of rock a few feet under
    gound. I'm planning on doing a concrete pier foundation (15 piers) for a 16x32
    cabin. My questions is: after the piers are poured if their not all the same height
    or level what would be the best way to level out the beams resting on top of them.
    Hate to sound silly but am only a novice builder and this part of the foundation
    is giving me fits. Also if anone has a better idea for foundation on that type of land
    that would be great. I will be renting a dozer for clearing and leveling the building
    site.

  2. #2
    Member Vince's Avatar
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    1st leveling the pad and compacting the gravel you WILL haul in... ( i built 3 on haystack and another 2 miles further up) your pad should not be more then 1 inch out end to end...

    2nd. when forming and pouring your piers, a string line and a level preferably a transit level will ensure they are all the same height, if not you will have to shim them or install adjustable cradles for that...

    you can get by much cheaper then pour your own with pier pads and Pier blocks already formed with the saddles from Fairbanks block. for ! $1000 after your pad is done you will have enough adjustment for the foundation... if you need to lift a Pier block to much a pressure treated 2x12 will raise them up or sheets of 3/4 treated ply wood cut down ... these are laid on the pier pad ( 24X24 ~$45.00) under the Pier block (12x12 ~$10 w/saddle) you will need one every 8" of length x 3 rows (15 ea) and set them back 12" from the edge so that you can skirt the cabin. 4x12 beams laid in the saddles with 9" TGI floor joist on 24" centers will get it done ...
    "If you are on a continuous search to be offended, you will always find what you are looking for; even when it isn't there."

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    Hunter: Might something like this be what you're looking for? http://www.loghelp.com/p-882-the-nortek-leveler.aspx

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    Was hope you would reply Vince, as I knew for an eariler post that you had lived up that way.
    Was planning on getting some gravel hauled, but was not planning on doing a full house pad. I
    will take your advise though. Can you tell what gravel is going far per yard or load and who
    much will I need for the pad. Is there permafrost up there, my property is up at the top of haystack.
    Sharmon Ct. off haystack ext. That design will save alot of drilling 8-10" holes. Edboo I did concided
    a type of screw like that one. But didn't like the idea of my cabin sitting only on 15 11/2" rods.
    1 more question Vince. If the 4x12 beam is moved in 24" from the outer edge won't I loose alot
    of support for the outer wall, it will be a 2 story with gable roof. Seems like all that load would
    be transfered to the floor joist.

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    Quote Originally Posted by hunter4361 View Post
    If the 4x12 beam is moved in 24" from the outer edge won't I loose alot
    of support for the outer wall, it will be a 2 story with gable roof. Seems like all that load would
    be transfered to the floor joist.

    Basic rule of thumb for bearing walls on cantilevers is not to extend the joists any further past the beam than the width of the joist; this means for 2x10 joists, you can cantilever 9 1/4". I prefer not to cantilever under bearing walls.
    " Gas boats are bad enough, autos are an invention of the devil, and airplanes are worse." ~Allen Hasselborg

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    Member Vince's Avatar
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    If the 4x12 beam is moved in 24" from the outer edge won't I loose allot
    of support for the outer wall, it will be a 2 story with gable roof. Seems like all that load would
    be transfered to the floor joist.
    the beam is 12 inches in to allow for framing of skirting not 24 inches. the TGI floor joist will carry the external wall fine as they span over the beams.

    as for the rest... yes there are spots of perma frost up there. i put a few septics in also... the rock type out that way is predominately a schist. ( rotten shale type) that when rubbed together will make dirt. also water is about 38 foot ( average ) at the top of hay stack. and 200 foot at the bottom... ( some one else can explain the hydrodynamics of a mountain over a river)
    "If you are on a continuous search to be offended, you will always find what you are looking for; even when it isn't there."

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    Member Vince's Avatar
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    Quote Originally Posted by cdubbin View Post
    Basic rule of thumb for bearing walls on cantilevers is not to extend the joists any further past the beam than the width of the joist; this means for 2x10 joists, you can cantilever 9 1/4". I prefer not to cantilever under bearing walls.
    thats correct until you get into the manufactured floor/rim joists and sill plates.. the reason for the 12 inch set back is that the pier lock would set under the wall with out it and not allow for skirting around the perimeter for cold weather applications and insulation.
    "If you are on a continuous search to be offended, you will always find what you are looking for; even when it isn't there."

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    Vince your right I meant 12" not 24". I understand now about that over hang and how much a certan joist will over hang
    and still support a load. About the permafrost. I from down south and my not no parmafrost when I see it. Most (95%)
    off the ground on my lot was covered with this thick(6") green moss and lots of little scrub willows(I think). So to close
    in the bottom I better make sure there"s no permafrost under my cabin correct? Also do you have an idea on cost of
    gravel delievered and the approx. amount I'll need for my 16x32 cabin. I will be grading the building level with a dozer.
    One last thing if I used 2x12 floor joist could they span the 16'. I had planned on using on the second floor as there would
    be no center support.

  9. #9
    Member Vince's Avatar
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    Quote Originally Posted by hunter4361 View Post
    Vince your right I meant 12" not 24". I understand now about that over hang and how much a certain joist will over hang
    and still support a load. About the permafrost. I from down south and my not no permafrost when I see it. Most (95%)
    off the ground on my lot was covered with this thick(6") green moss and lots of little scrub willows(I think). So to close
    in the bottom I better make sure there"s no permafrost under my cabin correct? Also do you have an idea on cost of
    gravel delivered and the approx. amount I'll need for my 16x32 cabin. I will be grading the building level with a dozer.
    One last thing if I used 2x12 floor joist could they span the 16'. I had planned on using on the second floor as there would
    be no center support.
    the moss is a good indication of cold ground, your really best to not disturb the frost at all... you scrape off the vegetation down to the schist, and immediately back fill with the gravel and compact. if you have the funds a layer of typar ( ground cloth) and 4" OF BLUE FOAM board under the gravel, will help insulate the ground from thawing. also make sure you have a cold crawl space, skirt it to keep the wind out but let it remain cold year round.

    as for gravel that will depend on your chosen site, elevation and amount needed to level the pad. your 16x32 will actually be a minimum of 20X40 across the level top of it with a slope for run off the roof to get away from the cabin itself. it is recommended that these pads be at least 12-24 inches above mean ground level for runoff and insulation.

    to give you an idea, my pad for a 30x 40 in 03 cost me about $5500 to have completed with my wife and i running the water and compactors for the dirt mover

    on the 2x12 on 16' centers you would still have a bouncy floor... strongly recommend TGI floor joist for both levels. a few dollars more but well worth it, not to mention if your building your own you can swing them around over your head with ease.
    "If you are on a continuous search to be offended, you will always find what you are looking for; even when it isn't there."

    meet on face book here

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    If you do have permafrost, be sure to allow for future shimming if some thaw settlement occurs down the road. As far as skirting goes, wind is your friend to preserve the frost. Pick yourself up a copy of "Building in the North" by Eb Rice and read it. $17 well spent!

  11. #11

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    Since we're talking about foundations...

    I'm building a 14x16 log cabin in the white mountains next summer, and I like the traditional look of having them set on the ground, rather than the functional method of setting them on pier blocks above ground. Is their a way to have the old fashioned look of a cabin set on or partially in the ground and still have it last?

    The ground is well drained at the top of a hill, white spruce and birch, I don't think I have permafrost issues based on the vegetation but haven't dug in to find out.

    Any thoughts?

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    I am very excited about his discovery given me by a friend. Check this out for any foundation that you don't want to break the permafrost.

    www.bigfootsystems.com Unlevel ground not a problem. If you can get to sand or hard ground you are good.

    George

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    Quote Originally Posted by George Riddle View Post
    I am very excited about his discovery given me by a friend. Check this out for any foundation that you don't want to break the permafrost.

    www.bigfootsystems.com Unlevel ground not a problem. If you can get to sand or hard ground you are good.

    George
    I have those supporting my cabin. It's new this year so it hasn't been through a winter. I wouldn't use them if I was building on thaw unstable permafrost.

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