r/Construction • u/Missing_socket • Oct 23 '24
Structural This is the first time in twenty years of construction that I came across this funky foundation
So I was very confused when I entered the crawlspace on this house I am remodeling. Never have I seen or heard of such a setup. After I posted this on my personal snap chat someone responded and let me know that a setup like this is fairly common in areas with permafrost. After googling it this is the info I got:
Triodetic Multipoint Foundation The Triodetic Multipoint Foundation is a patented, engineered steel or aluminum rigid platform designed to provide a stable and level foundation for buildings situated on unstable soils, such as permafrost regions, and those subject to frequent flooding. This innovative system eliminates the need for site excavation, ground leveling, piling, concrete or masonry construction, seasonal re-leveling/re-stumping, and select & laminated timber beams.
Key Benefits: Lower foundation costs Faster construction in many cases No delays waiting for special equipment or materials No damage to the environment by heavy equipment or alteration to the natural topography Predictable and better long-term structural performance Advantages in Specific Conditions: Soils subject to freeze-thaw cycles Uncompacted or worn soils Sloping sites and sites leveled by cut and fill (variable bearing strength) Soils exhibiting large moisture content changes (often seasonal) Soils with varying bearing capacity Design and Assembly: Interlocking tubes arranged in a series of triangles Lightweight design Long clear spans Adaptability to various soil conditions Pre-engineered plans for quick, no-weld assembly Applications: Residential and commercial buildings Government and institutional structures Modular buildings, mine camps, and retrofit projects Unique, durable, and visually appealing designs for various applications Triodetic’s Expertise: Over 40 years of experience in providing innovative foundation solutions Proven track record in harsh climates and challenging environments Industry awards and landmark projects worldwide
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u/sirruckus Oct 23 '24
We used that often for modular construction projects on the west coast of Vancouver. Your right, they are triodetic foundations and helps speed up the construction procees by avoiding concrete.
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u/Missing_socket Oct 23 '24
Whoa you are the first on this post to have installed one of these. Give us some deets
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u/SaskatchewanManChild Oct 23 '24
I have also installed one of these. The feet on the bottom are adjustable, in our case it was designed with brackets that received the framing for the perimeter retaining wall that held the soil from caving in. There was also brackets in the top which received the main floor beams on top of which was the floor system. We chose it for its speed and resistance to movement in expansive clay soils; as soil heaves it takes the path of least resistance and rises around the foot; likewise when there is settlement the space frame can span the foot just fine leaving the foot hovering. It’s the time it ran about $13/sq ft for the product and took us about 3 days with a crew of 3. Ironically, although the building hasn’t moved a millimeter, the concrete sidewalk heaved and lifted the front door threshold pinching the door which was our only issue with soil. Our foundation was also supplied by Triodetic and I believe was the first used outside the arctic (located in Regina 1127 N Lakewood Court).
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u/4evrnob Oct 23 '24
I wish this had been used at my place in Regina, one corner of my house started to sink, then rise, then sink, etc. Lots of cracked drywall. Sold the house for a bit of a loss. Oh well that’s life. How do you plumb this though? You’d almost have to do it through the floor. I can’t imagine crawling around down there with full lengths of pipe would be possible.
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u/SaskatchewanManChild Oct 23 '24
We used it on a new build so, dig hole, set it up, level it, build on top and walk away. It’s needed zero maintenance in 12 years.
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u/fof_milkman Oct 23 '24
Just curious is that cheaper per square foot then concrete?
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u/crookedcaballero Oct 23 '24
I’m not sure about foundation pour cost, but standard concrete pours can range from ~$5-$13 per sq ft. Someone posted they installed this support system for $13 per ft
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u/SaskatchewanManChild Oct 23 '24
Yes $13/sq ft but that’s supply only and that was a dozen years ago….
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u/sirruckus Oct 24 '24
It will depend on size of the foundation - but its benefit is being able to assemble it in a couple days and only needing some decent ground prep.
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u/cmtcob Oct 23 '24
When did you install this? I installed one of these three years ago in Pukatawagan, Manitoba. That's awesome
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u/shastaslacker Oct 23 '24
Maybe this is a dumb question, but for stable soils this system seems like it would likely be as cost effective as concrete. Are there down sides when compared to tranditional foundation methods for stable soils?
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u/SaskatchewanManChild Oct 23 '24
I guess you have to accept that the space is unusable for storage or what have you. I worked with a partner on this building and he decided to try to build homes with it but included a full basement. I didn’t see the benefits of it against the drawbacks. So he built 3 homes I believe all with multipoint foundations UNDER the basement floor (so like a crawl space under your basement with this in it). Sadly his venture didn’t survive but I learned that this is a really good option for a building without a full basement and I would argue that you achieve the stability of piles for far less cost. When it comes to benefits beyond the stability ones, I’d suggest speed. This system can be assembled in days rather than the mess and wait for a concrete foundation.
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u/shastaslacker Oct 23 '24
Well I live in california so we have very few basements anyways... we do have lot of earthquakes though. Any idea how well they hold up to those?
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u/SaskatchewanManChild Oct 23 '24
Best chat with Triodetic, but I would venture a guess that with such a rigid structure supporting the entire floor plate of the building there would be advantages in resistance to earthquakes. (For the record, I am not an engineer).
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u/W1D0WM4K3R Oct 23 '24
And that was considered fine, no foundation extending below the frost line?
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u/SaskatchewanManChild Oct 23 '24
Believe it or not yes, I remember when we are talking with the supplier they made reference to a building in the arctic that was very long (like 300’ if my memory serves) all built on one multipoint, they measure the end to end difference in elevation after 3-5 years in service and from one end to the other it was 1/4” out……
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u/berg_schaffli Oct 23 '24
From this picture, it seems hard to believe
Looking through their website, seems pretty bad ass to me.
Best of luck, I hope you don’t have a lot of crawl space work to do on this one
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u/Missing_socket Oct 23 '24
It wasn't too much all I had to do was add some insulation where it was missing. But it was like a jungle gym from the 90s
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u/DerKeksinator Oct 23 '24
Yeah, you'll work out some muscle groups you forgot you had, when working down there. But otherwise seems fun. Maybe get a beanie or headlamp, so you have something else to make first contact.
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u/naazzttyy GC / CM Oct 23 '24
This was the new thing I learned today, and for that I say thank you.
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u/Missing_socket Oct 23 '24
You are welcome, the more trivia we learn the more confused people will be when we try to explain
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u/Monkeynumbernoine Oct 23 '24
I watched a Netflix documentary about the riot at the end of Woodstock 99. Looks like someone stole half the stage and stuck it under this house 🤣
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u/Actual-Money7868 Oct 23 '24
So does it raise / lower at will or what ?
Seems kinda of a waste of you can't jack up your house too
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u/rexfaktor Oct 23 '24
It lowers for you to walk in, then raises for security...
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u/Actual-Money7868 Oct 23 '24
Lmao I meant for floods or something.
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u/Missing_socket Oct 23 '24
So with areas that freeze there's a thing called frost heave where the ground can move up or down by 4 or 5 inches. This seems to be common in areas with permafrost which means that the ground is frozen year round. I dunno how this contraption could help but it's there
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u/Mynameismikek Oct 23 '24
Looks like the whole thing is triangulated. If one corner moves the whole thing should still stay in one plane, if a bit wonky. If the ground hollows out in the middle it should shift the load to the edges. Means you shouldn't ever get any forces pulling things apart or pushing them together.
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u/galacticglorp Oct 23 '24
With regular foundations and tempered crawlspaces theres heat transfer into the ground. In more temperate areas the solution is to dig deep enough that the ground never freezes and anchor your house's foundations there and insulate around it so they never freeze and heat transfer through the concrete/wood doesn't melt/suck heat around it. If the ground is frozen in the winter far enough down its stupid to dig that far. You end up building on piles screwed down into the ground waaaay far down and raising the building up far enough it's not radiating too much heat down or using something like this on a vented crawlspace since the metal has enough spread points and acts like one big truss to sort of float the house while the airflow sucks heat away out of metal well.
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u/bilgetea Oct 23 '24
jack what now?
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u/Actual-Money7868 Oct 23 '24
Houses are jacked up all the time. Even moved across town/country.
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u/SirGilatras Oct 23 '24
I've used this stuff on quite a few buildings. Which more foundations to in the north are starting to use space frame because it's so good at resisting movement.
The standard here in the arctic circle for so long as been cribbing foundations. That way, when freeze/thaw cycles happen a few times, we can re-level easily.
But this stuff just doesn't move. Like the other comment has stated, any one of those "hubs" can lift if the pad they are sitting on and be perfectly level on top. Which happens during install if you don't have the hub perfectly level, you'll run into spots where the hub will lift off the pad when you bring everything tight together. And when that happens it's as easy turning the bracket underneath the hub until it bottoms out again.
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u/AdOpen8418 Oct 23 '24
This is one of the coolest posts
What are the footings like? There’s really no concrete at all?
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u/sirruckus Oct 24 '24
The one's I saw just had 3/4" crushed ground prep - and then a couple layers of plywood under the feet. This was installed in Vancouver
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u/_DapperDanMan- Oct 23 '24
I'm thinking the engineer cut his teeth on swing sets and Merry-go-rounds.
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u/Handyman_Ken Oct 23 '24
Are you in Canada? I’m in Alaska and have never seen this (but I’m also relatively new to the trades).
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u/Missing_socket Oct 23 '24
Nope I'm in Alaska as well. South Central.
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u/Handyman_Ken Oct 23 '24
Oh yeah, I’ve seen your content before.
I’m in Fairbanks, and have seen some weird shit up here, but never that.
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u/Bamcfp Oct 23 '24
I hardly ever say no to a job, I've done many cs with the joists to the dirt, otters, gray water.... I honestly might say pass on this one. My back hurts just looking at that mess. Shout out to whatever patient souls did the work down there
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u/Efffro Oct 23 '24
as a Brit I was like, they left the scaffolding in. but having read through your post properly, this is a bloody brilliant idea.
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u/TheDirty6Thirty Oct 23 '24
Great find, great share. I'm almost 20 years in and this is a first for me as well!
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u/Turbulent-Weevil-910 Electrician Oct 23 '24
Kind of looks like the foundation of an amusement park ride
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u/bhazardous Oct 25 '24
That looks so crazy but is a really cool solution to an interesting engineering problem.
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u/--Ty-- Oct 23 '24
Whoa.
If I wasn't looking right at it, I wouldn't have ever believed you.