DIY Tiny Home Pier Foundation | The Right Way

I did something very similar, but permitted. Here is what mine took to get an engineer's stamp: - 12" sono tubes - 24" flared-out footers (so I had to dig 24" holes) - 31" below-ground depth (I have an 18" frost line in my area) - 18" above-ground height (a minimum requirement for access) - Each pier needed QTY: 6 sticks of #5 40" rebar w/ QTY: 7 of #4 rebar 6" retaining rings (double-ring at top). - A much beefier (ABU46Z) Simpson post-base w/ 10" anchor bolt. That's not to say yours won't work, I'm just pointing out what was required for a permit. To other viewers: The vast majority of occupied spaces in the USA require permits, with very few exceptions. Best of luck with the build!

I dug eight 18 inch diameter holes with a 1000 lb mini skid steer with auger bit, 40 inches deep (my county requires 30 inch depth minimum, which is the frost line in my area). I inserted 18 inch diameter sonotubes down to 30 inches, and left the remaining 10 inches in direct contact with the soil. I cut the tops of the sonotubes 5 inches above grade (mark with laser level, and cut with jigsaw). I built wooden frames out of 2x4s that I staked down around each sonotube, and used poultry wire staples to connect each sonotube to the wooden frame from inside the sonotube, to prevent it from moving during the pour. I built cages out of #4 rebar, and set them in the holes with rebar chairs on the bottoms. Passed footing inspection. I bought a 5 cu ft concrete mixer from Home Depot (cannot imagine mixing all that in a wheelbarrow!), and have poured six out of the eight piers so far with 4000 psi concrete. Each pier is taking sixteen 60 lb bags! Home Depot dropped the pallets of concrete in my back yard, so I just use a Gorilla Cart wagon to move bags to where I'm pouring. I built a chute out of scrap wood so I can pour directly into each hole instead of having to move concrete from the mixer to the hole (no wheelbarrow or shovel needed!). I also picked up a concrete vibrator from Harbor Freight. Thing works amazing. I'm sore as hell. Taking the day off tomorrow (supposed to rain), but I'll finish up on Monday.

You realize that you can never adjust those post anchors. The thread is imbeaded in the concrete so when you turn that bolt it will not move. You should of sleeved the treads or Atleast taped them slowing them to slide up

It’s crazy to see Construction on the main stage now, back when I was a kid my dad was looked down on by Society as a Carpenter/Labor. Now he’s paid in Bay Area as much as a Doctor 😅😂😂

For all those arrogantly commenting about every little thing he did wrong, this guy was an engineer for a living, and now he’s doing what many of you do for a living: building structures. He can do what you do, but you can’t do what he does. You’re not on his level bro.

I wonder about adjusting your anchors. If you twist the nut down, it will strip the threads of the bolt, or more likely just strip the concrete. Usually that's OK, but it would leave the building weak to uplift in case of strong winds, tornadoes, or massive flooding.

I hope everyone realizes that you’re not getting the air out of a 4-6 foot cylinder of concrete by dunking half the trowel in the top part. Idk how much the structure will weigh but putting zero reinforcement in that concrete seems insane…even fiber fill, hardware cloth or wire fencing would’ve been worth the minor cost for peace of mind.

Where do you store all your tools?

I’m curious, no rebar needed? I’m working on my shed foundation. It’s only 192sq feet, I’m doing 4 16’ skids attached to piers for a total of 20. I don’t need a permit for this build, but they do say I need to do minimum of 24” deep 8” pier. I’m going 28” deep and I’m doing rebar, maybe overkill? 🤔🤷🏻‍♂️

Man, a drill with $15 mixing paddle would have saved you hours and calories.

You used the wrong type of anchors. Those are not designed for wet set. They also will not adjust as you're saying.

No rebar?

Is a bolt 4 in deep in concrete strong or capable enough to make this work long-term?

Take an actual beam, attach all anchors in the right place, Set it up on a make shift scaffolding suport so that your anchor feet reach into the holes correctly, then pour the concrete in the two exterior pillars, let cure, then pour the concrete in the inner ones. Perfectly alligned foundation beam without any tension. Rent a concrete vibrator attachment for your cordless drill pour one third of the pillar let the air out by vibrating, repeat for 2/3 and 3/3.

Dude get the HF concrete mixer. It’s cheap and works great for low volume. You are young now and think it is no big deal. Just because you can muscle through doesn’t mean you should. Later in life you will thank the younger you. Life is an endurance race.

Can you provide a little more info about permits and regulations? Like did you hire ana rchitect to submit plans to the city, or did you do it yourself? Also, did you need permits for septic and water? :)

Can you please help me with a question about piers? How do I know what diameter each pier needs to be? We have no permits where I live. My room addition will be 24'x14'. Can't seem to get a straight answer on this. Thanks a bunch!

Concrete without steel rebar is absolutely not gonna last. It will crumble with time. Always always add rebar to concrete.

Devon do you think this foundation is good for a container homes as well?

What are the dimensions of the house?