a small off-grid passive solar earthbag 'survival pod'

Hi Kelly!  I'm excited you're here and just noticed this opportunity to ask you questions!

I'm currently planning to build a small off-grid passive solar 'survival pod' (very earthship inspired, tiny-house type thing) that would be bermed into a southfacing hillside that is composed of very clay-based soil.

I am attaching drawings of my plans (still working on them but this is the idea) and wanted to know if you'd take a look and let me know if there are any grave structural mistakes I'm making, and also ask a few specific questions (though maybe the answers are all in your book, if so let me know).

Here are a few other questions i'm struggling with that you may or may not feel like weighing in on (and happy to hear from anyone else who has advice!  this is my first time posting on permies and I'm by no means an expert on anything just trying to figure out my plans based on books and what I've researched online, which is never finished it seems!)

1. Does the curved wall in the back have to be a perfect semi-circle for optimum strength against the weight of the berm?  At the point where the sides meet the small curved bathroom stall walls is this a weak point?  Should I not design it this way but have the 2 stalls curve back into the hillside as well (See drawing with shape question).

2. Does your book show diagrams of how to connect a water barrier (and if you have a specific plastic / ply type you recommend let me know) around the walls before you berm it in?  And how far down should the water barrier extend over / below the foundation slab?  I haven't gotten this deep into it yet but assuming there will be a gravel trench of some depth around the perimeter and that's where the plastic would end, over the gravel, and then we'd backfill the berm...

3. If I want to build the stairs to the loft "into" the the earthbag wall (appealing as could get more storage underneath with less support structure I am imagining) should this be treated wood to protect against moisture/rot from the bags as they dry out?  Would it make more sense to just build a simple stair-ladder from the loft without involving it in the wall building process?  Guessing the latter.  There's just something so elegant about having the stairs come out of the wall in a little partial spiral.

4. Same question with the lofted area-- if the loft plywood is resting snugly between courses of earthbags around the edges (with other beams for support toward the middle simultaneously framing the closet and kitchen counter area) does that plywood need to be treated or would wrapping a plastic barrier around the wood where it is squeezed by the earthbags below and above it be a suitable solution?  If this is stupid and the loft should only be supported from below without extending out into the wall let me know... I'm NOT a building expert of any kind, just a DIY figure-outer type person.

5. Have you ever built an earth-tube for ventilation (PAHS system type concept or nowadays Earthships are incorporating them combined with venting skylights for bringing cool air through in summer) in one of these?  I assume I would just build the tube right into the earthbag wall between bags near the floor level, any particular type or size tube you'd recommend using for this part since it'd have a lot of weight on it and would need to conduct temperature of the earth?

6. How might we go about building walls with anchors built in to hang shelves and cabinets on?  I know having storage in such a small 'pod' is key and I'd love to have shelves or cabinets over the kitchen counter area at least.

7. I'm planning to bury a cistern for rainwater catchment to the side of the kitchen behind the shower stall... ideally we could even have a gravity fed tube from the cistern through the wall to a faucet over a sink, and we could fill a Berkey for drinking / cooking water, fill our sun shower bag in the sink to hang outside to heat, etc. Let me know if there's a standard way to build in areas for bringing things like wiring from solar systems or water pipes in through an earthbag wall please!

THANKS!  I hope I didn't ask too much or too much, I know this ends today but I just saw it and thought "WOW great opportunity to get some expert advice on my project!"  Even if you just respond to one or a few of the above Q's I'd be so thankful.
best,
Sarah

This never got a reply somehow, and missed the zero replies catcher I think...seems like these questions could be helpful to others too.  Any chance you can come back for one more post, Kelly?  thanks for all you've shared with us!

Copying from Kelly's post on the "welcome Kelly Hart" thread:

quote:

I have quite enjoyed hanging out at the Permies forum over the last week, and expect to check back in periodically.

I would encourage anyone who has questions about natural building and sustainable architecture in general, not just regarding earthbag building, to check out http://greenhomebuilding.com/ask_the_experts.htm. I have been directing questions to over 30 experts in virtually all aspects of this since the turn of the century. Many of these questions and responses have then been published on the website, organized according to topic on the appropriate pages. There is a true wealth of information available here!    

One point I would offer is digging the structure into the hill slope like that tends to cause water issues. Mike Oehler describes this as the "first thought" house in his book, and the issue is that gravity will pull water down the hill and off your roof, to the back wall of the house where it will work its way through the wall and cause you problems. Instead you want to slope the soil so that it always has a path off the house to drain away.

Mike uses what he coined as the uphill patio, having the windows facing uphill towards a patio where you can grow food or decoration, and the patio allows you to direct all water around and away from the house. The green roof then continues to follow the hill slope which allows you to have a hidden little retreat, and you can use dormers and different options for providing windows on all 4 walls without causing water to back up anywhere.