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Small Cabin Forum / Cabin Construction / longevity of building with skids/girders
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cjm
Member
# Posted: 21 Jan 2019 14:06
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I've read many posts about skid foundations and I've seen comments about the longevity of different foundation types... along the lines of "if you want the cabin to last decades, do a full foundation."

While I can see a full perimeter foundation outlasting other types - is there really any reason that a well-done skid-type foundation (e.g., scrape away top soil, level crushed limestone, put blocks on cement pads, put two girders on the blocks) wouldn't last just as long as cement piers? Both will have exposed girders.

I have in mind to build a 16x32 cabin in East-Central MN.

Just
Member
# Posted: 21 Jan 2019 15:36
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To big IMO.our pro here says max 16 x20 .

xtolekbananx
Member
# Posted: 21 Jan 2019 16:31 - Edited by: xtolekbananx
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I used to own 16x28 cabin/barn that was on skids, 4 4x4 skids and then 2x6 floor on top of that. Skids and floor was pressure treated. The pad was all crushed rock compacted and then cement blocks. I know that cabin is still there and did not move an inch after many years. Now I have a cabin also on skids. It used to be 10x20 but I build an addition, so now it is 18x20. Just like you said I removed top soil and left hard clay, build a 20x22 box from pressure treated 6x6 and filled it with rock. Compacted everything and moved the existing cabin on top of that then added an addition. So far so good. I can tell that it does heave a bit, but nothing I cant live with. If I had the money I would build real foundation and a real cabin, but Im on a budget and the whole foundation cost me about $700, rock, wood and lag bolts. Here is the picture
20180917_163920.jpg
20180917_163920.jpg


cjm
Member
# Posted: 21 Jan 2019 17:04
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Quoting: Just
To big IMO.our pro here says max 16 x20 .


Just: Can you say more? I know there are many posts on here I haven't read - but it looks like a number of people have done 16x24-32. And I know you can buy prefab buildings 16X40. Owen Christensen on here looks like he's done a lot and said once that 16 or 20 is the widest he'd go for two skids. Is your concern about length just that is it more difficult to level? I'm certainly interested in learning as much as possible to avoid problems later!

xtolekbananx: thanks for sharing!

Just
Member
# Posted: 21 Jan 2019 18:10
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If you can look up some of OwenCristensen posts and comments in cabin construction you can get some good info about building on skids .He is a pro and has built many cabins on skids .
Some of his recommendations are only two skids and no larger than 16 x20 .Ihave built a few but none that big.

fiftyfifty
Member
# Posted: 21 Jan 2019 18:14
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Owen Christensen built mine. The bigger one (16 x 24 +6 foot of porch) is up on piers because the ground sloped so much that just skids wasn't an option. The little one (10x16) is on 2 skids directly on the ground, not even scraping away the dirt or using gravel. I asked him whether I needed to do that, and he indicated it wasn't really needed. And I don't think he was just saying that, as ground prep is something he does for an added fee and he could easily have convinced me I needed it and made extra money if he had wanted! He told me that these methods last decades. How many decades, I'm not exactly sure, but he's been building ~40 years I think.

cjm
Member
# Posted: 21 Jan 2019 18:51
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Quoting: fiftyfifty
The bigger one (16 x 24 +6 foot of porch) is up on piers


Thanks, fiftyfifty... when you say piers, do you mean concrete piers below the frost line or just blocks on the ground? And is the porch on the same support-system, basically making it a 30ft building?

fiftyfifty
Member
# Posted: 22 Jan 2019 15:32
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The piers are treated lumber below the frost line. The porch is on the same support system, so 30 feet long.

fiftyfifty
Member
# Posted: 22 Jan 2019 18:33
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During progress of the 16x30.
posts2.jpg
posts2.jpg
posts.jpg
posts.jpg


KinAlberta
Member
# Posted: 25 Jan 2019 22:05 - Edited by: KinAlberta
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We have two cabins. Both sit on concrete blocks dug into the ground. (Depth I don’t know but very unlikely to be anywhere deep enough to get below our frostline.) The original topsoil was left untouched and not scraped away. Both need some minor levelling work however I’d like to do more to strengthen the beams to better spread the load across the blocks to reduce pressure points where water can soften the underlying ground. (At a couple points some blocks show some tilt. Letting eaves trough water to dump for years directly onto the ground at two corners of one end didn’t help.) I would love to just run steel I beams under them, raise them up and insulate their floors bug it’s not likely worth it.)

Both are basically in very decent condition.

Both are 70+ years old. (I think my father built one in the mid 1950s and I know the other is listed as being built in 1945. At one point it was a 16x24 cabin on another part of the lake. My uncle moved it onto my parents property and then added another 8’x24’ section to the front. That too may have been done in the 1950s but maybe early 1960s.

Their dimensions are:

24x24

24x30

Beams are 8’ apart on both. I’m not sure, but I think the 24x30 cabin has 2x10 beams and floor joists.

carr0406
Member
# Posted: 30 Jan 2019 12:24 - Edited by: carr0406
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I followed Owen's posts and went with a 16x32 on skids in Northern MN. It hasn't moved in the last two seasons but after this week's weather I'm going to check on it. I removed top soil, added poly sheet and gravel with pads every 5.3 feet. Clay soil but water runs away from foundation and have 2 foot overhangs.
20150516_173437_HDR..jpg
20150516_173437_HDR..jpg


cjm
Member
# Posted: 1 Feb 2019 18:25 - Edited by: cjm
Reply 


Thanks, carr0406. I'm curious to hear how it looks when you go up!

These posts have been super helpful. I'm still interested in anyone else's thoughts about longevity... is there any reason a cabin on skids won't last just as long as a cabin on a full foundation?

Dave1986
Member
# Posted: 23 May 2019 03:39
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Hi there! You sure? I owe a cabin, got it from my dad, and it has skid foundation and I will even make a photo and post it here to show you what happens with it after a while (a while=15 years). In some spots wood is rotting, there are problems with ventilation, the result is mold. Also a couple of times I was there I saw a rat. It's not the kind of closeness I want to have with nature. So it's basically falling apart. I'm considering tearing it down and build a new one and I read a lot on this topic and I want to try out coupling rebar. They say it's easy to install and it's way more strong. As far as I know, Hardman company uses it for different kinds of buildings so I'm pretty sure it would be enough for a cabin. I've first read about the technology here http://www.hardman-de.com/technology.html, then googled for more infiormation and it seems to me that's not a bad idea. At least no mold and rats. Your thoughts?

Brettny
Member
# Posted: 23 May 2019 07:08
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Im sure if you spend alot of time making these skid foundations perfect they will last...but so will almost any other foundation.
Even a good skid foundation has one bad feature. Its very hard to work on the middle skids if any leveling is needed.

We will be doing sonotube foundatio. For ours and putting the carrying beam up 4ft for good ventilation and any future upgrades/repairs.

Peewee86
Member
# Posted: 23 May 2019 20:03
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CJM,
Do you plan to have it permitted and inspected? If so what will the inspector allow?

It seems like those who have used skid foundations have gone with that method because of cost. And possibly to have the personal satisfaction of completing the build by themselves. My guess is most of them are done without a permit. If your budget allows it I would recommend doing something else. I have helped a friend build a sonotube cabin foundation. I’ve used sonotubes myself for decks and sunrooms. There is some work to excavating frost depth holes and belling out the bottoms. There is work and costs to pouring cement. When it came to starting my place I elected to go with an insulated floating slab foundation. I had to put a value on my time. It was more cost-effective for me to pay somebody else and to have it done right.

My foundation is 15 x 36 so it’s similar in size to what you are planning. The cost of the cement work was under $3500 and I didn’t have to lift a finger.

The cabin I am building is also in East central Minnesota. Mille Lacs County.

ICC
Member
# Posted: 23 May 2019 21:26
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Quoting: Dave1986
I read a lot on this topic and I want to try out coupling rebar. They say it's easy to install and it's way more strong. As far as I know, Hardman company uses it for different kinds of buildings so I'm pretty sure it would be enough for a cabin.


Not sure why you think that is good stuff for a cabin? It would appear to be great stuff for building dams, bridges and large steel reinforced buildings. You need a special high powered compression clamp machine to crimp the connectors that bridge from one rebar length to another. Probably very good for high $$ projects; definitely not a DIY. In fact I'd wager that most contractors you would be likely to hire for a small cabin job wouldn't even have the equipment.

I do believe a concrete slab or concrete perimeter foundation with crawlspace provides a vastly superior foundtion when compared to skids.

Also chances are good that if there is a building permit process in place for the location a skid cabin will not pass muster.

NorthwoodsGuy
Member
# Posted: 24 May 2019 19:50 - Edited by: NorthwoodsGuy
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One note on skids: a lot of it is going to depend on climate and soil. I live in Northern MN close to Owen. Where we are it gets cold, but frost heave is limited by minimal topsoil and quick drainage. You are lucky to go down 18" before you hit shelf rock. Our cabin is 12x16, and while we see some settling and heaving, it is minimal. So skids work pretty well here.

You have to balance the work saved with not doing piers upfront with the annual task of potentially leveling things in the spring if you settle or heave.

KinAlberta
Member
# Posted: 24 May 2019 20:27 - Edited by: KinAlberta
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I’d love to go with screw piles, adjustable brackets under steel I-beams.

In our city, full concrete basements are the standard. Cracking foundations are also known to happen. (Two nearby neighbours have spent tens of thousands dealing with problems with their full foundations.) My second garage is on a concrete pad and it is 24’x26’ and built in the 1970s. The pad has some minor cracking and a slight slope at one point as a result. (Maybe due to eavestrough water saturation at that corner.) If it continues to drop - say drops more than say an 1 1/2”, then I may get it mud or foam jacked. However my attached garage floor with two walls on a full foundation also has some cracking. Even I n my house there’s a slight rise in the floor in one spot. Maybe a construction error or due to the fir joists. So, I’ve seen problems with pretty much everything.

Here they say limit it to under 400 sqft if on skids.

CABIN FOUNDATION OPTIONS UNCOVERED
https://www.knottypinecabins.ca/who-we-are/blog/2018/08/cabin_foundation_options_unco vered/

cjm
Member
# Posted: 11 Jun 2019 10:40 - Edited by: cjm
Reply 


My thought is that having it raised off the ground should mitigate the risk of rot/moisture issues. I don't think that individual piers (e.g., sono tubes) have enough benefits to be worth the cost for a small cabin. I think that piers on a full-perimeter footing would be ideal, but I don't want to spend that much.

So, I'm tentatively moving forward but we reduced the size to 16x24. We brought a skidsteer up there for a day and got a driveway roughed in (900ft long).

Then, for the cabin, we scrapped away the top soil, filled the trenches with gravel, and tamped it. I set 5 blocks on each side for the girders to sit on. I used two 4" thick solid concrete blocks to make a 16x16 base, then set cinder blocks on top. I think I might stack one more cinder block though, so it is a little higher off the ground. I still have a little grading to do next time we can get the skidsteer up there to make sure that the land on the right side of the picture slopes away.

I'm still open to any suggestions or observations. I keep debating if I should pay for some other foundation... but then I'm sure my wife will say "well then let's make it bigger" and it will balloon into something else. Right now, I can handle everything myself. It won't have running water. There are no building permits required (just a site permit). So... onward for now.
IMG_20190531_141218..jpg
IMG_20190531_141218..jpg


KinAlberta
Member
# Posted: 11 Jun 2019 19:25
Reply 


Not sure if cinder blocks are the best option but most are good for 50+ years. We have a couple buildings sitting in them. A few have cracked. Also some were laid wrong with the holes horizontal and not vertical. I plan to someday replace a few with something better.

cjm
Member
# Posted: 11 Jun 2019 20:28
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What would you use instead?

Brettny
Member
# Posted: 12 Jun 2019 07:45
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By the looks your building a skid foundation but on blocks. If you get freeze thaw you will have to level it every year i hear. Not so with tubes to below frost line.

KinAlberta
Member
# Posted: 12 Jun 2019 08:34 - Edited by: KinAlberta
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I was looking at some solid granite blocks at a landscape shop the other day. I might take another look at them for use as cinder block replacements. Also, there is/was different qualities of cinder block available.*

On levelling a building on blocks, if water is kept away the ground should freeze evenly and so any lift should be even. As I’ve posted in the past our 1950s cabins on blocks have stayed relatively level for 70+ years now. (The error was setting up rain barrels then taking them away and allowing eavestrough water to dump straight on the ground at two corners for 10-15 years. The clay softened and we had an 1” or so of settlement. At around the 30 year mark my dad had levelled it and I recall him saying 1/2” in 30 years wasn’t bad. So I think he was thinking freeze/thaw would cause more movement.

Unfortunately with the 24x30 main cabin beams sitting near flush with the ground I can’t get under it so accurate levelling will be tough to do. The blocks under the centre of the cabin with be very dry so I don’t think they’ve experienced any movement at all in 70 years.

Note: Piers can settle too as well as experience lift by frost heave. In our city our full foundation homes suffer from cracks and movement in their concrete foundations. However a full basement doubles the footprint’s living space so that’s fantastic.



* when the lake water rose and eroded our beach we tried temporarily supporting the front of our boathouse with some cinder blocks. Some absorbed or were splashed with freezing water, froze and cracked or crumbled.

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