Two Major Techniques
There are two terms I’d like to introduce to the earthbag home building public. One is the saddle bag. The other is the shim bag.
Okay. Fair enough. These are terms used to describe two specific earthbagging adjustment situations. Probably no one else uses them, but they work for me…so let’s see how they apply.
If you’ve cruised other earthbag web pages, you may have noticed that they make everything seem pretty simple and straightforward. Fair enough. It is…sort of. However, I’ve noticed a couple of situations that arise regularly but are simply not discussed anywhere else:
1. The constant need for partially filled bags to make a wall’s length come out right.
2. The occasional need to level up the corners due to “corner droop”. (More about that later.)
About wall length: An occasional random, unpredictable row of filled bags is going to come out “just right” every once in a while. Not that often, though. Empty bags are uniform, but shovel or pour them full of dirt and they just…aren’t. Slight differences from bag to bag to bag in length, width, and depth do tend to add up. For those all too frequent situations, I use the shim bag. If a reader would like to point out that shims are not usually 25 pounds of dirt in a polypropylene sandbag, I agree. But it’s my house and my hub and…so there!
There’s really only one point that needs to be made about the shim bag: After the right amount of earth is in the bag, it’s just fine to slam it into place any old which way with the flap simply tucked under rather than tied off. That is, fill the hole and move on, no big.
Why doesn’t anybody talk about (gasp!) Corner Droop?!?! With a straight-walled earthbag home, it’s inevitable, yet there seems to be another wall…of silence. Have all the other builders figured out a magical way to avoid this phenomenon? Doubtful. If they had, wouldn’t they be bragging instead of quietly editing–or maybe photoshopping–their graphics before putting them up on the Internet? I’m thinking the answer is, “Well, Duh!”
It may be remotely possible that the folks who sew their bags shut rather than tying them off…nah. The ends would still tend to be shaped differently. The problem might be less, but it wouldn’t be nonexistent. With the tied-end bags, the problem is relatively huge. Every bag comes out a little “flatter and wider” at the bottom end and “narrower and thicker” at the bunch-tied end (the end which was open before being filled with dirt). Board-slapping or tamping the bags as flat as possible does reduce the difference…but does not completely eliminate it.
Add in the fact that each corner can only be composed of “wide flat shallow tails”–because the bunch tied (formerly open) end could burst open and spill all the dirt–and the corner must droop as the layers add up. My solution to Corner Droop, then, is the saddle bag, so named because its shape reminds me of a (rather small) saddle bag of the type seen on western saddles belonging to working cowboys. In a way, it’s simply another shim bag. On the other hand, there are differences: The saddle bag is working to fill vertical space while the shim bag addresses “reach” or horizontal space. It is also designed to drape over the drooping corner (on the underside) while coming out level (on the upper side).
Today, our home walls received a first set of saddle bags on the corners, placed between the 6th and 7th layers of earthbags. Each unit received no more than two shovels worth of earth, sometimes a bit less. The bags were folded at about the halfway point so that there was plenty of room to tuck the bottom corners and then massage the contents into the desired shape.
But first came the 4 point barbed wire. The walls would fall down without that stuff. A special, short chunk of wire was cut and then formed into a sort of “ribbon loop” to grab the saddle bag firmly. On one corner, I spaced off and started to place the bag without first laying the barbed wire loop–and immediately found out why we (earthbag builders) use the stuff: The saddle bag tried slip-sliding away for real. With the wire in place, it was as solid as the proverbial Rock of Gibraltar.
Shaping the saddle bag properly is definitely an art, not a science. It does work, though. In our home’s case, it looks like most likely two or possibly three sets of these will be needed to reach all the way to the top of the wall…and the wall will be relatively level when we get there.