Here in Texas, we don't have permits or any sort of government involvement when building anything outside of city limits. But I grew up in California, and the government wanted to be involved in everything. I'm guessing Vermont makes you get a permit for everything too.
I'm shocked at how complicated this is. It seems to me that all you need is a strong retaining wall that will also function as part of your wall. My way of thinking is to just increase the amount of rebar and make the forms thicker. Then it's just a matter of paying for materials and a crew to get it done.
As a Contractor, I've learned that the most expensive way to get something done is to hire people to do the thinking for you. Then when you hire the crew to do the work, they change everything because the person you hired to do the thinking didn't actually know anything about what is being done. When I need to hire out work, I talk to the Contractor I'm going to hire and avoid all the thinkers. He's done it before, he knows what's needed, and he doesn't charge for planning it out. He just gets it done.
A septic system is the only thing I would need a permit for, and I'm not building one of those, so no permits required. I can do whatever I want. Around here a pole barn just won't last because the poles will move with the freeze/thaw cycle. They are quick and easy, just just don't have the longevity of other approaches.
As for "thinkers" vs "contractors", I half agree. Maybe even 3/4 agree. I'm a former engineer myself, though a different kind, and I know all too well the phenomenon of engineers sitting behind desks looking at specs and drawings, yet having never seen a construction site, let alone actually built anything. Pretty much all trades rag on engineers for being clueless, whether it's mechanics, or contractors, and a lot of it is well deserved. But contractors also only have part of the puzzle. Yes, experience counts for a lot. But at the same time a lot of people just keep doing things wrong over and over again because they haven't seen it cause any problems. It doesn't mean it's not a problem, they just haven't seen it. And when circumstances change, what you did before somewhere else might not work again. In my experience, it takes both.
In this case, one issue is the force of the retained soil pushing against a tall wall and wanting to overturn it. And if that soil is saturated with water, the force goes up significantly. The tipped force is counteracted by the "toe" created by the thickened edge of the slab, both from its leverage, and also from its weight. In houses where there is a floor deck on top of the wall, that provides a significant amount of the required support. I don't have such a deck, so all the force has to be carried by the wall. The end result is just as you describe; make the wall thicker, add more rebar, and start pouring. But how much thicker, how much rebar, how thick for the thickened edge, and how wide does it need to be.
I'm listening to what contractors are suggesting, and our current thinking is MUCH more in line with what they suggest vs what the engineers came up with. I have pretty much discarded what the engineers came up with. But I do want to check what contractors are suggesting to make sure it passes some basic engineering checks.
As for wall thickness, that has become an interesting topic. I think I mentioned that one guy didn't want to form all the pilasters, and instead just make the wall as thick as needed. That's pretty much what you are saying, I think. The challenge is that the columns need an 18" landing zone, so that would force the wall to be 18" thick which strikes me as crazy thick. It might be OK to shrink that down to 16", but it's still a really thick wall, and a lot of extra concrete. But maybe that is the right way to go; just simplify the job by throwing concrete at it. What do you think about a 16" or 18" thick wall?
Where we are right now is to just pour a thickened edge slab floating on a bed of crushed stone. Then pour the stem wall on top of that. There will be a perimeter drain, but I have been worried about water coming in between the slab and stem wall seam. One guy mentioned some seal that they have used successfully. Maybe you know about that? Also current thinking is a 12" thickened edge for the slab extending 5' inward towards the inside of the building, tapering to a 6" slab in the interior. Then 10" thick stem walls with 18" pilasters.
I welcome any suggestions.
