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Small Cabin Forum / Cabin Construction / Foundation suggestions, remote off grid cold and snowy
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yoopermike
Member
# Posted: 26 Apr 2022 22:25
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Hello, newbie here and to building in general with just a deck to my credit. I have read a bunch and the options on how to proceed sometimes make my head spin, so hoping I can get suggestions fine-tuned to my particular situation.

Building a small cabin (unsure of precise dimensions, 12x16 or 12x18 or 14x16 or something around 200sqft) with vertical 8" green hemlock logs (50lbs per cubic foot from what I read) and shed-style roof with short wall 7ft and tall wall 10ft. We get a lot of snow in the UP. The log walls will weigh a bunch (rough estimate for this size cabin is probably close to 20k pounds). So I want foundation to be good enough, and maybe even overkill. I have minimal electricity and no running water, and access to the site will be impossible for anything other than my 4wd truck, so no trailers, mixers, no cement trucks. Mixing enough concrete in a wheel barrow with a shovel and no water source besides a spring a ways away will be impractical. I don't know precise soil type though most of this area is pretty sandy. Can I just dig a hole with shovel at the build site and grab hold of a chunk of soil and/or do jar test to figure out how much sand, silt, clay, in order to determine bearing capacity? Won't be precise, but precise enough?

Since concrete will be too difficult I had planned to just put pt 6x6 posts to below frost line on some type of footing and backfill with dirt (I'm 40yrs old, if well-drained they should last the rest of my life, hopefully). As I will be digging with a rented 2-man auger and a shovel, digging 24" wide holes will also be difficult, to accomodate wide pads. How wide will I need to go? 14"x4" concrete cookies seem like they may not be enough, or will they? Any thoughts on composite footing pads? How many piers would be good to spread out the load more (at least 9 of them, so 8 around perimeter spaced 6-9ft and one for beam across the center, or even a couple more than this)? What would be adequate beams on which to rest joists, 6x6s or built-up (3) 2x6, or larger?

Thanks in advance for your help.

neckless
Member
# Posted: 26 Apr 2022 22:54
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i poured a footing by hand this past summer small mixer two people ..
would probly take u a good day once prep was done....

Brettny
Member
# Posted: 27 Apr 2022 08:53
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You can find good underground rated wood posts but good luck actualy finding them. Things like creosote filled utility poles may work, but again you need to find them. New quality poles are going to cost more than renting a towable mixer and concrete for sono tubes.

Tim_Ohio
Member
# Posted: 27 Apr 2022 09:05
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I've seen people just throw the entire bag of concrete, unopened, into the hole and set the foundation post on it before back-filling around the post. This might be a consideration. It will harden over time. If you have a lot of rocks in the area, they could serve as a kind of footer. As long as what you put in the hole has a solid nature to it and won't allow the post to sink, and it is set below the frost line, it will serve as a footer. The idea is not to allow it to sink into the soil or move around on you.

Tim_Ohio

Brettny
Member
# Posted: 27 Apr 2022 10:12
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You can find good underground rated wood posts but good luck actualy finding them. Things like creosote filled utility poles may work, but again you need to find them. New quality poles are going to cost more than renting a towable mixer and concrete for sono tubes.

gcrank1
Member
# Posted: 27 Apr 2022 10:19
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Used railroad ties?

travellerw
Member
# Posted: 27 Apr 2022 14:09
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You could do an on ground foundation like me and W1llie did. However, that requires bringing in a bunch of materials including about 2 tons of gravel.

Personally if I were you, I would look into buying an IBC tote and then using it to bring water in for concrete piers. The town closest to my building site has a water fill station and will fill and IBC tote for $7 (thats 1000 liters). As long as you have access to water, the wheelbarrow and shovel method is actually quite efficient.

I would also shy away from any used wood products. At least the stuff around here is being removed for a reason. The railroad ties are pretty much used up and the creosote is no longer working.

BRADISH
Member
# Posted: 27 Apr 2022 14:35
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Quoting: travellerw
I would also shy away from any used wood products. At least the stuff around here is being removed for a reason. The railroad ties are pretty much used up and the creosote is no longer working.

I would echo these thoughts. Given the build size/weight you are looking at, I think hauling in water for self mix concrete is going to be one of your leading options. While I've seen railroad ties work, they werent supporting nearly as much weight as you're proposing.

yoopermike
Member
# Posted: 27 Apr 2022 14:48 - Edited by: yoopermike
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Thank you all for the responses. Moving water and using wheelbarrow and shovel may not be a huge deal, would just take longer having to wait for things to cure etc. Dug into the ground at the site today, seems mostly medium sand to me, and quite dry, especially so consodering that lower areas of the property are a mud pit. Digging was surprisingly easy, felt like I could have dug nine 5ft deep holes in no time.

As for cabin weight, that is with green weight of logs. They will of course lose nearly half that weight if not by wonter then within a year, so should that factor into foundation choice? Once it is built it will likely be late summer warmth followed by heating season, so they should dry out fairly quickly. And my estimate may have been on the high side but I prefer overkill and overstimation.

BRADISH
Member
# Posted: 27 Apr 2022 14:51
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Quoting: yoopermike
As for cabin weight, that is with green weight of logs. They will of course lose nearly half that weight if not by wonter then within a year, so should that factor into foundation choice? Once it is built it will likely be late summer warmth followed by heating season, so they should dry out fairly quickly. And my estimate may have been on the high side but I prefer overkill and overstimation.

I think given your fore-mentioned high snow load, you'll want to plan estimate on the high side of things regardless of your log moisture content. IMO.

NorthRick
Member
# Posted: 27 Apr 2022 16:07
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Quoting: yoopermike
Thank you all for the responses. Moving water and using wheelbarrow and shovel may not be a huge deal, would just take longer having to wait for things to cure etc. Dug into the ground at the site today, seems mostly medium sand to me, and quite dry, especially so consodering that lower areas of the property are a mud pit.


Given this, just dig through the organic layer until you hit the sand. Add some crushed gravel until you are back to grade. Set a patio block or pour a 4-6" thick concrete pad. Build up from there.

Unless you are subject to really high winds, you will be fine.

spencerin
Member
# Posted: 27 Apr 2022 19:48
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If you want to do the 6x6 post option, you should be able to find UC4B (permanent foundation grade) PT lumber at big box stores (Lowe's, Menard's, etc.). Maybe in-stock, maybe special-order, but you shouldn't have any issue finding them. Rot won't be an issue with them (they're code-approved for this use), but where rot does occur with posts in the ground is at grade level and below several inches. That said, you can buy sleeves on Amazon that protect the posts from ground-contact moisture. Some people are adamant against using wood posts in ground for anything, but with UC4B and sleeves, you're good to go. Seems like a solution that would work well for you.

Brettny
Member
# Posted: 27 Apr 2022 20:02
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Quoting: travellerw
I would also shy away from any used wood products. At least the stuff around here is being removed for a reason. The railroad ties are pretty much used up and the creosote is no longer working

I would normaly echo this because its usualy true but a few years ago I bought about 13 20ft telephone poles, the good old ones. The part in the ground looked nearly black and new when I cut in them. I even cut some of the upper sections into 6x6 posts and they also look nearly new. Creosote is alot different stuff than RR ties. They dont sit in dirt as much. Also passenger rail can be completely different than say a RR yard track tie.

yoopermike
Member
# Posted: 27 Apr 2022 21:12
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A friend of mine said just dump bags of quikrete in around my posts. I would think that would draw moisture to them and causing rot, even with ground contact treated posts. Maybe not before I die, but maybe so... in which case I would not want to deal with trying to fix a foundation in old age.

Brettny
Member
# Posted: 28 Apr 2022 05:16
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If your going to do that why not just fill the hole and put the wood ontop of the concrete? Then why not just actualy mix it and do it correctly?

Aklogcabin
Member
# Posted: 28 Apr 2022 10:31
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We used cedar utility poles for our remote log cabin foundation. They were very easy to get. Just stopped by aplace that installed poles. There's lots of road construction going on and they have to move the utilities. Maybe you could check out a road crew n ask.
Anyhows they made for an easy foundation. And cedar has natural oils in it that resist rot and bugs do not eat it. The bottom portion is treated, not sure if it's creosote as I believe that hasn't been used in a years because of toxins. I have not heard of creosote deteriorating but maybe it does. I do know that the poles will last a long time. I wrapped tar paper around mine, not so much concerned about ground contact as having the frozen ground having something to grab in to. And cousing hydronic jacking or frost heaves.
After the poles are in. A laser level will make cutting them off at the correct hight is easy. I cut a shoulder into the top of ours to hold the floor 6"x12" beams and bolted them with 1/2" galvanized bolts.
So putting the poles in and leveling out the cabin floor was easy. And I was able to get the poles out using snogos in the winter cut to 8' lengths.
Our cabin has stood through 7.2 earthquakes and 12' of snow yearly and the floor is still perfectly flat. In fact I just checked it a few weeks ago. Been up 10 years or so now.
My suggestion would be used utility poles for remote work.
Side of cabin
Side of cabin


travellerw
Member
# Posted: 28 Apr 2022 11:28
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I thought I would post this video for inspiration. Its cool to see him fix a botched foundation.. but it also shows what can be done hand mixing concrete. Dude hand mixed like 24 piers in a small plastic bin, some of them under the actual cabin.

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

Tim_Ohio
Member
# Posted: 28 Apr 2022 12:13
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After watching that, I'm glad I used rebar in my footers on up through the pier.

As for using poles in the ground, it might be a consideration to somehow attach them to your footings so that they stay on center.

Wow! I'm glad I will not have to do what he had to.

Tim

yoopermike
Member
# Posted: 28 Apr 2022 12:20
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Thank you all again for replies. What about nailing some pt 2x6s around the bottom of poles below the frost line and backfilling with gravel and sand? The weight of the gravel would rest on those 2x6 attachments and keep the pole anchored, so to speak, no?

yoopermike
Member
# Posted: 28 Apr 2022 17:38
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Another thing to consider... I dug a 45" deep hole with post hole digger (min depth per code is 42" here). Build site is at top of a hill, sandy soil, so should drain well. Went back an hour later and there was a small puddle in there. Not much, but enough to form a small puddle anyway. As I know nothing about foundations or soil or water tables--is this normal, will it be an issue in determining foundation? Keep in mind two weeks ago we still had two feet of snow on the ground.

spencerin
Member
# Posted: 28 Apr 2022 22:15
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I'd partially screw in multiple large galvanized lag bolts (instead of 2x6s) and backfill in around those as "catches" against vertical movement. But, that's me.

A small puddle shouldn't be of concern. Dig the hole even deeper and dump gravel in the bottom and place the post on top of the gravel for this reason.

Again, if you use wood posts, make sure it's UC4B grade. It's code-approved for burial/permanent wood foundations.

I think the worry for rot is overblown if you do it right. I have had a UC4A (ground contact, so less treated than UC4B) piece of lumber sitting on the ground and fully exposed to the elements for about 3 years now. No rot whatsoever. Rot also needs oxygen to happen. That's why the part of post buried deep in the ground can avoid rot, whereas that part at and just below the surface is more prone to rot - access to oxygen. Hence the sleeves I suggested earlier.

The others have suggested some good alternatives as well. I just think a wood post foundation done right would be just fine for your needs.

Brettny
Member
# Posted: 29 Apr 2022 08:20
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Quoting: travellerw
I thought I would post this video for inspiration. Its cool to see him fix a botched foundation.. but it also shows what can be done hand mixing concrete. Dude hand mixed like 24 piers in a small plastic bin, some of them under the actual cabin.

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

I watched that video and it's a perfect example of why you dont skimp and try to save time, money or labor on a foundation. He did alot of work and the cabin being over each pier makes things way harder.

Tim_Ohio
Member
# Posted: 29 Apr 2022 08:44
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I've seen, in reading, where posts are often drilled through, then a piece of rebar is pushed into the hole so that it comes out from both sides. And then, it is done again, at 90 degrees in another location at the lower end of the post. Perhaps the use of galvanized bar stock would be better than rebar. Or, even galvanized pipe, readily available for plumbing applications. I'd still either have a base of solid concrete or large stone to set it on, though. It's still possible it could sink in just a dirt pad or insufficient gravel bed. Remember, the top of the footing, which your post will sit on, needs to be below the frost line. The treatment of the post, with the above mentioned rebar/galvanized piping or whatever, is to prevent frost-heave (lifting). I'm skeptical as to whether the footings were deep enough for the cabin referenced in the video, since the connection to the concrete footer shifted and the pier was not plumb in some of the images, before he began repair. I dunno, it's just my observation.

Tim_Ohio
Member
# Posted: 29 Apr 2022 08:46
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I might add, it might be important for the rebar to be below the frost line as well. I dunno, maybe others would disagree.

Tim_Ohio
Member
# Posted: 29 Apr 2022 08:48
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Oops, I also wanted to say, in a conventional footing, you "bell-out" the hole for the concrete to form a wider area from the pier to prevent up-lift. So, for this reason, the rebar would be serving the same function and it might be important for it to stick out below the frost line, as well.

yoopermike
Member
# Posted: 29 Apr 2022 10:34
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Thanks Tim, that all makes sense.

gcrank1
Member
# Posted: 29 Apr 2022 10:34
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If you have ever set a round bottomed decorative rock in the flower garden youve probably watched it slowly sink. For that same reason I want a flat bottomed hole with a flat bottomed rock or 'crete pad.

yoopermike
Member
# Posted: 29 Apr 2022 11:15
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This may be a very naive question, but how do you ensure perfectly flat and level tops and bottoms to a poured concrere footer when it's 5ft down? Can't exactly reach down there with a trowel.

gcrank1
Member
# Posted: 29 Apr 2022 11:29
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No need to be obsessive, unless you want to
Flat'ish is Ok.
Easiest is probably to dig the hole, Bell it, put an ice scraper in to scrape the bottom flat'ish and pour in some concrete.
The top will self-level if the mix isnt too stiff.

Tim_Ohio
Member
# Posted: 29 Apr 2022 11:33
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It will level itself. No trowel is necessary for a footer.

It's just a base of material, at least 6 or more inches thick, depending on the expected load. The drier you
mix it, the stronger it will be. Too much water is detrimental to concrete strength, is what I've learned from my research. Of course, it has to be workable in certain applications. Go with what the bag suggests for the amount of water to add.

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