Frank Senter

I want to build a two-story shop, preferably from materials found on the land. Right now, I'm considering a little 5x5x6 well house just to get experience.

If I give the well house a tall footing and a broad roof, will a lot of moisture enclosed in the small space cause any issues? Being filled with cold water, the pressure tank and pipes do sweat profusely in Missouri humidity, and a well house usually gets closed up and forgotten. It will have a gravel floor to the depth of the rubble trench, so drips won't create puddles. I'd like to also experiment with clay-slip as insulation on the inside, and a lime plaster on the outside.

So I dug down about 3' at my sight and tried another soil shake test...I still can't find a line differentiating the silt from clay (see my jar picture).
Playing with it to make balls and "worms" I noticed a couple of things. No matter how deep I go, I'm going to have a lot of fine roots in the soil mix--I can pick out big stuff, but will little 1/16th inch diameter pieces broken roots matter if left in the cob mix? Straw is organic, right? The next thing I noticed is that this soil is sticky only when there's enough moisture to give it the consistency of fresh play-dough. If it's drier, it will still mold into solid shapes, but it rubs off my hands fairly easily. In the play-dough consistency, it holds finger prints somewhat, and will roll out in a pencil-thin or smaller worm, and usually hang over my finger in a 4-5" strand. I say "usually" because when it does break off, I find that it does so where there's organic or small gravel. The pinch-a-ribbon test is more challenging--I can occassionally get the ribbon to hang almost 3", but more often it breaks, again where there's root and tiny gravel/large sand particles. If I sieve this soil to clean out the trash, will I lose the real-soil condition in testing?

I also packed a couple of 1.5" cylindars (PVC pipe) so I can measure shrinkage. The photos were after the samples sat overnight. The very thin layer on top of the shake test sample is liquid, not a clay layer. My county's soil survey calls this soil "silty loam." Shouldn't I see a line between the silt and clay? Can the silt to clay transition be so evenly graded that one can't see a difference?

Glen, what is the right way to attach flashing to an earthen wall? I can't picture an adhesive being able to stick anything, whether EDPM or coil stock to a "dirt" wall. I've already learned from modern connstruction that nails rarely create a water-tight penetration (I've always wondered about the thousands of holes in house-wrap that are created when you staple or nail it on).

I'm still unsure what soil I have. The county soil survey calls it silty-loam, meaning the equal proportions of loam (sand/silt/clay) are a little lean in the sand/clay proportion and a little rich in silt. It's slick when wet, like clay, but drains well. A jar test shows a little less than 1/3 sand, but the remaining stuff settles out so evenly that I can't distinguish a line between the sand and silt. It doesn't "rope" or ribbon that well, but a dropped ball sticks together pretty well.

I pounded out three 9x18x3.5" RE blocks. The first wouldn't compress because the soil was too moist, the second was a lot harder, but 7 days later crumbled at the corners a bit easier than I think it should, and although I mixed lime into the third batch, it delaminated at the level where I'd added more soil to the form. I haven't added any straw or sand into the mix yet.

I've read a lot about cob and rammed earth, seen a lot of pictures detailing ways to attach the roof to the TOP of the wall, but none showing how to connect something like a porch roof to the SIDE of a wall. Here in central Missouri, that's an important detail in modern construction methods--I assume it's got to be even more important with earthen walls. How do you make that connection water resistant, particularly if it is a free-flowing (rounded) vertical wall? Modern construction techniques insist that stucco plaster is somehow supposed to overlap a metalic flashing...but how do you get a metal flashing to conform to and adhere to a cob or RE wall? Also:
1. Wouldn't a plaster finish simply crack horizontally where it flows over the flashing, and just fall off?
2. Will the plaster (and yes, I know it can't be portland cement based) just wick water back up into the wall?

A little background:
Somewhere I read 'look out your window, and build with what you see." Well, that would be silty loam, anywhere from 5" to 5' thick on 25% north-facing slope under a mixed oak and hickory canopy, sliding down to a little creek with a moderate amount of coarse sandy gravel. I would love to build a two-story workshop: a lower level for grungy work, like a one-bay garage, and an upper level for fine woodworking and art studio (no dirty-handed mechanics allowed). Outside, I envision a shed roof (attached like a porch roof to the tall vertical exterior wall) for a little saw-mill operation.