Ardilla Esch

I built a straw-clay house that mostly had dimensional lumber trusses (hidden in the walls) with some exposed timber framing.

1. I think rectangular timbers would be easiest to build - especially since you want to conceal them. Also you can take advantage of smaller lumber with concealed ladder trusses. You attach the temporary forms to the trusses when packing the straw-clay.

2. Concealed framing is no problem - in some ways it is easier. You do need to prepare the joints more where the plaster covers the timber/straw-clay joint, but that is pretty simple. The wood will be fine as long as there is a good roof, foundation, etc.

3. The timbers we used were fresh felled trees (forests were closed due to fire hazard until we absolutely needed the timbers). There was more twisting and checking of the wood, but it turned out fine. The species of wood affects how timbers behave when green, but it generally works.

A lot of sand and gravel operations will have crusher fines. Some crusher fines are good for floors as is. Sometimes you may need to add sand or clay to make them perform better.

Crushed cement might work - you would probably have to add clay soil to it.

Even a stiff wood floor flexes. This will make earthen materials crack like crazy and likely spall off. It might work if the material is fully saturated with oil and fully bonded to the floor boards, but it would be a serious challenge.

I would definitely try test pieces on plywood before committing to a floor.

It's good that you taped the seams. The plaster will crack along the joints if you don't. Good surface preparation is key to any plaster.

In my experience lime plaster over earthenplaster works fine if there is good tooth to the earthen plaster (can't be crumbly or too smooth).

Mixing lime into earthen plaster is trickier. Too much lime makes the clay a less effective binder. I have found up to 10% lime (percentage of binder by volume) is generally o.k.

You could probably mix lime into the slip for light clay straw.  I have never done this.  I haven't had any issues with insects or other critters in the clay straw. You may be trying to solve a non-existent problem with this. Personally, I wouldn't do it, but It would probably work.

Type S lime is fine. For plaster I like to have it soaking for weeks before use, but that isn't necessary. Protect yourself when mixing lime.

I realize this is probably a little late to resolve your issue...

The driller was on the right track with the gravel pack but the material size was wrong.  The slot size of the well screen should be based on the sediment size the well is installed in.  Then the filter pack particle size is based on the screen size and aquifer sediment size.

You mentioned 10,000 slot screen.  I think you are talking about ten thousandths of an inch slot (0.010") which is about the smallest slot size used in wells.  So that was appropriate.  However, the filter pack size sounds like it was way too big.  The filter pack should be the smallest size that has about 95% or more retained by the screen.  So a 0.010" slot screen with very fine sand or silt aquifer would have a filter pack mesh size of 20/40 (see attached chart).  That should hold back the fine aquifer material and still let water through.  The well driller will still need to develop the well to clear out the fines and get the filter pack as clean as possible.

This is pretty basic well design.  Though some drillers only know 'the way they have always done it'.  I've run into drillers who place pea gravel as a filter pack no matter what the aquifer sediment size is.  Not only does that mean you may be pumping sand forever, it can create voids that can put assymetric force on the screen and collapse it.

For what it is worth, I am a geologist/hydrologist and routinely design wells.

5 feet of water column is not much to exchange heat with.  My guess is it would not be worth the equipment to plumb it etc.

My parents have a closed-loop geothermal system with three 200 foot wells.  It works well for the most part.  They had one cold winter where the glycol going through the system actually froze the groundwater adjacent to all three wells.

The heat capacity of a shallow well wouldn't get you that much heat. Especially if the well isn't pumped.  You get more heat if the water is pumped regularly

It could be done. I think you would want areas at different stages of completion so people could work all stages. Otherwise there is a significant amount of time between layers drying and oil applications curing.

12 inches is not a firm maximum wall thickness.  You can go thicker - particularly in drier climates.  A common rule of thumb is that the walls dry about one inch per week (6 weeks for a 12" wall).  However, I think our 12" walls dried in 3-4 weeks.  If you have decent drying conditions you could go thicker than 12" if you wanted.

Another thing is that you can change the mix to get more insulation value or more mass.  Typically, people make a lighter mix for the north walls and heavier for the sunny sides.  Also, the light clay straw walls perform better than the R-value would indicate due to the effect of the thermal mass in the walls.

I would recommend against layering the walls with dry straw in the middle.  First, it would be a pain to install with any consistency. Second you would be making planes of weakness parallel to the wall surface.  You could easily get sections that spall off.  One of the beauties of light clay straw is that the material makes cohesive, uniform density walls.  Layering the walls would disrupt the cohesiveness of the walls. You are better off making the walls thicker or using a lighter mix.

Maybe if you ran the leaves and vines through a serious chipper/shredder then dried it partially before bailing.  I don't think you could get uniform density bales without chopping it in some way.   it would be a great use if it worked.