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Small Cabin Forum / Cabin Construction / Foundation trouble
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mojo43
Member
# Posted: 15 Jun 2021 14:30 - Edited by: mojo43
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I built my tiny home around 10 years ago. It's built on a hill and every year things slip forward ever so slightly. This year this happened and now I am not sure what to do...
20210613_142118.jpg
20210613_142118.jpg


mojo43
Member
# Posted: 15 Jun 2021 14:35 - Edited by: mojo43
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Not sure why that pic came out sideways...
16237823096143027038.jpg
16237823096143027038.jpg


Brettny
Member
# Posted: 15 Jun 2021 14:38
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What size Is the post and what size is the sonotube?

mojo43
Member
# Posted: 15 Jun 2021 14:40
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6x6 post and 10 inch sonotube I believe.

Brettny
Member
# Posted: 15 Jun 2021 15:36
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Becids the movement every year your really not leaving much meat around the post for the tube not to crack.
Can you tell us more about the structure? Size? Frost depth? Anything else you can?

mojo43
Member
# Posted: 15 Jun 2021 15:41
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So the post was too big? The structure is a 9x12 A frame tiny house. Depth is 4.5 feet and that's supposed to be below frost level I believe.

DaveBell
Moderator
# Posted: 15 Jun 2021 16:04
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Home Depot has 18" tube. Put in a temp support first to the ground. Dig that mess out. Use a 18" tube. Put in rebar vertical 4 corners and wire horizontal pieces of rebar around at 3 levels. Use 5000 PSI concrete. Mix in sand and gravel per instructions.

paulz
Member
# Posted: 15 Jun 2021 16:16
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Not seeing the whole picture, a couple thoughts:

Put in new tubes outboard of the structure with beams running underneath. Maybe put a deck or porch on top.

My cabin is also on a hillside. It hasn't moved, touch wood, but I have steel cables attached at each end tied to large trees on the uphill side. Not so much for creep but, as I'm in earthquake territory, to keep it from tumbling down the hill.

mojo43
Member
# Posted: 15 Jun 2021 16:31
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Quoting: paulz
Put in new tubes outboard of the structure with beams running underneath. Maybe put a deck or porch on top.


Interesting. I like the deck idea, but I am not picturing the beams. Would they attach to what I already have in the ground?

Quoting: DaveBell
Home Depot has 18" tube. Put in a temp support first to the ground. Dig that mess out. Use a 18" tube.


Ughhh, dig it out? Damn that sucks. I guess I have no choice at this point though? The sonotube looks cracked only a foot under ground and the rest looks fine I think. Would I not be able to add to it? Just looking for an easier fix it that's possble...

paulz
Member
# Posted: 15 Jun 2021 17:16 - Edited by: paulz
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Quoting: mojo43
Interesting. I like the deck idea, but I am not picturing the beams. Would they attach to what I already have in the ground?



Beams sitting on the new tubes, running under the cabin, either replacing or underneath the current beams. Then put decks on top of what's sticking out.
Or you can dig out what you have like Dave says, if that's possible.

This is just something I've thought of for my cabin in the event something happened. I'm no engineer. I made the mistake that's often mentioned here, in a rush to build something, anything, and skimped on the foundation.

gcrank1
Member
# Posted: 15 Jun 2021 17:32 - Edited by: gcrank1
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Ive seen a lot of things on the old farms Ive been around.....you know: hey, lets save this building!
9x12 aint so big (yeah, Im sure you know that living inside), my Ice Shanty repurposed as the Tool Shed/Power House is 8x12 on an old pop-up camper frame that was beefed up widened and extended. Even so, it is still an inadequate frame for road hauling but my point is: yours aint too big to be sitting on blocks ('cause mine is on wheels);ie, a 'floating' foundation. The hillside is moving downward, your cabin along with, especially with it 'stuck into the ground'.
Imo, Leave it topside and cable the back end to a/some trees like Paul and dont make this into more work than it needs to be.
Or, for even more simple, run the cables to those front posts 'from the tree(s)', backfill the sonotubes cracks with some 'crete and dome for water run-off.

Brettny
Member
# Posted: 15 Jun 2021 19:56
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9x12...abandon what's there and just put it on blocks that are fully covered from driven rain.

Why would they even use sono tubes on such a small building?

Brettny
Member
# Posted: 15 Jun 2021 19:59
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9x12...abandon what's there and just put it on blocks that are fully covered from driven rain.

Why would they even use sono tubes on such a small building?

mojo43
Member
# Posted: 16 Jun 2021 15:11
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Quoting: Brettny

9x12...abandon what's there and just put it on blocks that are fully covered from driven rain.


Thanks for all of the responses. What would happen if I put just that corner on blocks?

DaveBell
Moderator
# Posted: 16 Jun 2021 18:26
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I don't see any aggregate in the concrete mix. So the mix will be weak and crack. Look how it cracked vertically and what appears to be spall fragments from the outer edge.

In one pic, it appears one corner of the frame is resting on a solid concrete pair, the middle one does not contact the pier and the left one barely has any resting area for the frame work. If the frame is resting on all six piers, what is the 6x6?

Read all of the posts. Black wet spongy ground, on a slope. Shed of Doom part 2?
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146043_1_o.jpg
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35465_2_oaa.jpg
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35670_1_o.jpg


DaveBell
Moderator
# Posted: 16 Jun 2021 18:27
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Will all six piers fail?

mojo43
Member
# Posted: 16 Jun 2021 18:41
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Quoting: DaveBell
Shed of Doom part 2?

Very dramatic haha

It has been a while, but I do remember mixing the concrete and adding rebar. Not sure what you mean about them not making contact as they all did when I first started. The back right post is where I miscalculated and only had a few inches resting on the post. It slid off a few years ago so I added this new post which then cracked like this. Does your post help me? Not really. Would love help

As it happens a few of the other posts are starting to lean forward as the ground moves.

DaveBell
Moderator
# Posted: 17 Jun 2021 08:02 - Edited by: DaveBell
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Quoting: mojo43
The back right post is where I miscalculated and only had a few inches resting on the post. It slid off a few years ago so I added this new post which then cracked like this.


We are trying but we are not getting complete information to develop a good solution. So you have had two piers fail now. Would have been nice to know that up front. In a previous post you talked about wet soil and water filling in a pier hole at 4 ft. You may have built on an underground aquifer or hillside drainage channel.

It looks like the frame is resting on top of completely solid concrete piers. But the first pic of this post shows a 6x6 IN the concrete. Are they all like that or just one?

Did you mix in gravel in the concrete mix? If you didn't, the mix is weak on ALL the piers and you may have all of them fail over time. Are the piers resting on bedrock or wet soil?

There are so many issues here that there may not be a single solution other than start over.

DaveBell
Moderator
# Posted: 17 Jun 2021 08:11
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For now I would put a level on the floor, in the middle, and record how much lean. Measure how much the bubble is off center and which direction. Measure north to south, east to west, nw to sw, ne to se.
Measure every month and record on paper. We might be able to save your life.

Brettny
Member
# Posted: 17 Jun 2021 08:37
Reply 


Quoting: mojo43
Thanks for all of the responses. What would happen if I put just that corner on blocks?

I would put all them on blocks. The whole building has shifted I'm guessing.

gcrank1
Member
# Posted: 17 Jun 2021 20:22
Reply 


Awww, come on....Ride that avalanche down!

DaveBell
Moderator
# Posted: 23 Jun 2021 00:11
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Left to Right in the picture. There is a car door so you are able to drive into the site. So you can trailer in gravel. To the right of the car door is a rock formation. Get the down trees out of the way. Measure for a new 9x12 foundation using the rocks. Are the rocks six feet apart so they can be used for two of the piers? Excavate the other four holes to see if there is more rock to be used. Excavate to the right of the two rock formations to see if these are surface rocks or a bedrock formation. To the right of the cabin is uphill to the right so you are currently in a hill drainage path, both from the uphill direction and from the right. The soil may not be load bearing. And with water drainage, the cabin is on an equivalent of quicksand. Lets try to save this cabin before it falls over. Don't add anything more, the objective is to disassemble and reuse the materials.

If the three new holes to the right of the rocks have the same poor soil, an alternative may be a concrete slab using those rocks in the slab. Take this very slowly, step by step, with all details posted here so we can help you recover.
49327_3_oa.jpg
49327_3_oa.jpg


gcrank1
Member
# Posted: 23 Jun 2021 21:35
Reply 


The good news is that the structure isnt too big to be able to deal with!
Yes, it will be challenging, and it must be done with forethought and Safety, but unlike some this one can be handled.

neckless
Member
# Posted: 23 Jun 2021 22:29
Reply 


really its 9x12 think about it ...... the tube is cracked but whats the wood post sitin on .... the full tube underneath dont even worry about it stop the water from goin in there maybe mix some grout and shape it on there to stop water getin in wood and swelling that ...

redneckpaul
Member
# Posted: 24 Jun 2021 00:15
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This is not rocket science.....its a 9X12 cabin as others have pointed out. Get your buddies together, get some liquor and some semi auto weapons, have some fun and fix this thing!!

ICC
Member
# Posted: 24 Jun 2021 09:16
Reply 


WTF

gcrank1
Member
# Posted: 24 Jun 2021 09:55
Reply 


Ive seem vid of a bunch of Amish picking up and moving a building. Buds plied with Bud, etc. could do the same thing. Such 'motivation' is used around here regularly.

ICC
Member
# Posted: 24 Jun 2021 13:48
Reply 


I can understand beer or whatever after having the guys help out with a big job. I don't see what firearms have to do with construction work unless you want/need one handy in case a bear drops by the site like can and does occur here in the mountains.

I am not anti-gun; I have a gun room with a historical collection of guns, flintlock to modern day. But guns and liquor do not belong together at the same time, same event and that jumped off the page at me.

snobdds
Member
# Posted: 24 Jun 2021 14:55
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Quoting: ICC
I can understand beer or whatever after having the guys help out with a big job. I don't see what firearms have to do with construction work unless you want/need one handy in case a bear drops by the site like can and does occur here in the mountains.

I am not anti-gun; I have a gun room with a historical collection of guns, flintlock to modern day. But guns and liquor do not belong together at the same time, same event and that jumped off the page at me.



I'm sure he was embellishing to show how much of a mountain is made of this mole hill.

It's really not hard of a fix, one just has to get over the mental hurdle and get to it.

Royalwapiti
Member
# Posted: 20 Jul 2021 18:50
Reply 


Watch this video and never bury your wood in the concrete piers, set the treated wood post on top of concrete.

https://www.youtube.com/watch?v=IMVsJcCO2fM

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