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Small Cabin Forum / Cabin Construction / Pin Foundations
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jregier
Member
# Posted: 10 Apr 2022 08:40
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Hello,

I am gathering information on building a new cabin. My site is 6kms by ATV through a rough muddy trail. Packing in a significant amount of gravel and concrete will be a challenge. The soil does not drain well and I assume it is mostly clay. I have had serious frost heaving issues with the current cabin, see "Cabin Structure Movement" post.

The pin foundations look to be a good product for my application, easy to transport and install. Here is a link to the website: https://groundframes.com/how-it-works/#installation

Has anyone used or knows of someone that has used the column pin foundation? Did it work well? Any issues?

They want geotechnical and structural engineering reports to design the pin foundation. Any recommendations for these services in the Parry Sound Ontario area? Not sure if I will be able to get a geotechnical engineer out to my site... hopefully they are outdoorsy.

rpe
Member
# Posted: 10 Apr 2022 08:56
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Glad to hear you are considering starting fresh. It might cost more up front, but down the road I'm sure you'll be glad you went that route.

I've seen videos of those pin foundations, and they look like a clever idea for softer soils. I don't know how well they would handle the up-lift forces you'll experience in winter though. As an alternative, you might want to consider screw piles. Mascore is a company near Brantford that I believe has a dealer/installer in the Parry Sound area. If your soil is relatively free of rocks that could be an option. They do have portable installation equipment that can be used for remote locations as well.

Are building inspections required? If so, talk to the local inspectors. They should be able to give you some ideas of what the common solutions are in your region.

Brettny
Member
# Posted: 10 Apr 2022 10:04
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With almost 4mi of ATV trails to have to bring things in I would do a block foundation and expect to have to level it every year. Theres really not much point in spending big bucks and hauling tons and tons of concrete, stone or other heavy materials in if it's just going to move and sink in.

Huge big wide pads can be poured on site. With really soft soil I wouldnt hesitate to pour a 3'x3' pad to put blocks or even wood blocking on.

ICC
Member
# Posted: 10 Apr 2022 10:27
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My experiences with wet and clay soils is limited. But we always worked with engineers and use heavy equipment as needed. Long and deep piles, usually driven, were the norm.

That pin foundation does not mention frost at all but say an engineer is needed. I do wonder if the pins are able to resist freezing uplift. Personally I doubt it.

For DIY in a remote spot I think you are stuck with smaller structures that have to be releveled frequently. Or you will need an engineer. Wet soil, especially clay, is a bi*%h to build on. Doubly so when there is a 4 foot frost depth.

I would try to keep width to less than 16 ft as one can usually do that with just two lengthwise beams and piers/supports. Maybe a short overhang cantilever (just the depth of the floor joist.

Or a floating concrete slab works, but it sounds like you cannot do that with any relative ease.

Build an ark? .

BRADISH
Member
# Posted: 11 Apr 2022 15:15 - Edited by: BRADISH
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Quoting: ICC
That pin foundation does not mention frost at all but say an engineer is needed. I do wonder if the pins are able to resist freezing uplift. Personally I doubt it.

They do mention it on their website, so at least they take it into consideration:

"PFI’s technology is based on soil mechanics and geotechnical engineering principles. Tributary (bearing, uplift, and lateral) capacities for projects are calculated based on the interaction of the soils and the inclined bearing pins."

"The structural design, building materials, and environment (i.e., high wind, snow load, frost depth) all have to be considered when calculating loads. Structures can have some areas where loads are concentrated and other areas where the loads are spread out. Based on the structure, these loads may be handled by a continuous/semi-continuous foundation like the Ground Frame Beam or Ground Frame Saddle. Or the loads may be handled by a stanchion or pier in the case of the Ground Frame Column or the Diamond Pier. "

Not sure how much it can stand, but it seems to be accounted for.

Pretty cool looking tech! If you end up going this route post lots of pictures! I would be very interested to see it installed.

jregier
Member
# Posted: 12 Apr 2022 10:50
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I spoke to the company here are some notes for anyone considering this type of foundation:
1) They require a minimum soil bearing capacity of 1500psf - I am unsure what my soil is but if I use the OBC allowable bearing pressure of soft clay it is only 865psf.
2) They require geotechnical and structural engineering to design the pin foundation system
3) Budgetary cost of $140-$160 / linear foot + freight from the US... upwards of 20K for a 25'x25' structure with a center beam.

This foundation system does not sound financially feasible for my cabin build even if my soil checks out. So, back to the drawing board.

I am considering concrete piers on 2'x2' footings below frost or the floating block foundation Brettny mentioned and just dealing with relevelling every year. If I went with the latter, are there any issues with building a long structure and keeping it 16' wide? I am thinking 16x36 maximum size

Brettny
Member
# Posted: 12 Apr 2022 11:37
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Quoting: jregier
upwards of 20K for a 25'x25'

Wow that's pricy. You could damn near gravel the 4mi road in for that price.

With blocks it's best to not have a 3rd skid/girder if you cant get to it to relevel. You dont really need a 3rd skid with a 16' wide but use an interior layout program first to see if 16' will lay out like you want.

jregier
Member
# Posted: 13 Apr 2022 09:13
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I am now investigating helical piles, a company in my area said they shouldn't have an issue getting their equipment to my site.

BRADISH
Member
# Posted: 13 Apr 2022 10:49
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Quoting: jregier
I am now investigating helical piles, a company in my area said they shouldn't have an issue getting their equipment to my site.


Nice. I have heard of great success with the helical pile in our area (which sounds similar to yours soil-wise). I know in our area the provider has a small track mounted rig (walk behind I believe) so maybe they are using something similar.

I didn't end up using the helical pile mostly because I wanted to be elevated off the ground further than they could support - however with limited solutions, it sounds like it may be the best bet for you. Keep us updated!

rpe
Member
# Posted: 13 Apr 2022 11:58
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Quoting: jregier
I am now investigating helical piles, a company in my area said they shouldn't have an issue getting their equipment to my site.

Would be interested in hearing what you find out. Pics if the install goes ahead as well!
Bradish - How high up off the ground were you going? I've seen these helicals used up to just above grade, and then a 6x6 post with bracing up to the structure above.

rpe
Member
# Posted: 13 Apr 2022 12:31
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After some further lunchtime reading on the diamond piers, it looks like they have done extensive research on the frost heave issue, and have had very high success rate with installs in those areas.
https://www.diamondpiers.com/frost-heave-other-forces
They claim the diamond-shaped underside of head splits the rising soil as it freezes, like an icebreaker in the Arctic! Given what I've experienced on our site, I am a bit skeptical.

ICC
Member
# Posted: 13 Apr 2022 18:01
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Quoting: rpe
https://www.diamondpiers.com/frost-heave-other-forces

I looked at the ESR report and the code compliance document for MN that Diamond Piers lists on their webpage.

The ESR specifies a minimum soil PSF of 1500 and the MN document refers to the specs in the ESR. The Diamond Pier web pages all seem to refer to 1500 psf soil as the minimum required.

Without a Geotech test and report, I would be reluctant to spend much money on a foundation system that might not be much better than a cheap DIY effort built on surface slabs with provision for constant or annual re-leveling.

ICC
Member
# Posted: 13 Apr 2022 18:02 - Edited by: ICC
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Quoting: rpe
They claim the diamond-shaped underside of head splits the rising soil as it freezes,


I have my doubts about the veracity of that claim. But no proof.

We have built on helical piles with excellent results in freezing climates. But those needed a soil test to be permitted.

MJH
Member
# Posted: 20 Apr 2022 17:42
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Quoting: ICC
I looked at the ESR report and the code compliance document for MN that Diamond Piers lists on their webpage.

The ESR specifies a minimum soil PSF of 1500 and the MN document refers to the specs in the ESR. The Diamond Pier web pages all seem to refer to 1500 psf soil as the minimum required.

Without a Geotech test and report, I would be reluctant to spend much money on a foundation system that might not be much better than a cheap DIY effort built on surface slabs with provision for constant or annual re-leveling.


The guy who sold me the cabin timbers was originally also going to put the whole thing up and he uses diamond piers. He put 6 of them in where the cabin was going to go.

I have pictures of a cabin he put on diamond piers that he claims was done with permits. I couldn't find anything saying they were to code for a dwelling (in Wisconsin... although I think the UDC says they are good for decks). Ultimately I pulled them out (wasn't as hard as you'd think) and went another direction, but if I was doing something small and under-the-radar I would definitely consider using them.

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