1.) Grab bag by
neck with one hand & grab seam on bottom of bag with the other
keeping bottom seam of bag parallel to ground.
Invert bag, letting dirt run down towards tied-off
Shake bag, distributing dirt uniformally.
3.) Fold top of bag under
& lay in
place (butting this end up against the seam edge of previous bag).
4.) Give bag a good shaking
to ensure even
distribution of dirt (bag should be roughly rectangular).
5.) Continue laying bags,
every 3-4 laid bags & checking your work with a level.
Part of what makes this
fun is that this is an organic process. Shaking &
your dirtbags is something that comes easy. You'll
master an almost intuitive ability
make corrections when
irregularities pop up. Once it "feels" right, use your levels
start tamping (you'll find you can use your tamper to make
3 or 4 foot
2 - sturdy
ladders & planking
for hoisting &
as walls rise)
There is some controversy over whether or not the soil in your bags should be wetted before tamping. Moistened dirt generally
achieves a higher degree of compaction
after tamping, and - when allowed to cure in hot weather - dries like
soil is clay-rich, pre-wetting will cause the clay will swell (expand).
This could be a good thing.
The principle argument against wetting is
that if your structure isn't quite vertical, or if you work too fast
& get ahead of yourself,
or if the weather isn't quite hot enough (or is
too humid in your part of the country)for a quick cure, your
underlaying bags can
"ooze" (read: become distorted) from the weight above them.
Wetted bags are, perhaps, best achieved by
mixing the soil with water in a wheelbarrow and then filling the bags.
Messy, but this
the best control over your mix. Two or three people can set up an
assembly-line that's fast & efficient, and each person
can trade off. This may be the best technique.
Since we provide pre-filled bags,
we've experimented with a couple of different techniques to wet the
dirt after it's bagged. (This
refers to the water-resistant polypropylene bags; burlap bags,
obviously, are in a different category.)
One technique is opening the bag, adding a
pre-determined amount of water, tying the bag closed, and then mushing
it about (fun!)
till if feels suitably squishy.
Another technique (still in
development!) is building what might, at first glance, look like a bed
of nails - a piece of plywood, about
12" x 16" (the same size as our tamped
bags), liberally embedded with nails. The board is placed on a
horizontal bag on the ground,
nail points down, and the tamper is used to impale it. Since our
pre-filled bags tamp down to a solid three inches, 16d nails (3 ½")
can pierce both sides of the bags in one fell swoop.
A good soaking with the garden hose,
or placing the impaled bag in a tub of water, allows the dirt
within to become uniformly
moistened, without compromising the
bag's integrity. Exercising judgement as to 'how much water is the
right amount' is crucial
here; overly-soggy bags won't tamp, they'll just splat &
mush. Remember, this is an organic, tactile process (labor of love!).
The bottom line? For small structures
(garden walls, raised garden beds, etc., we think it doesn't really
matter. However, for larger
structures (most especially anything you can walk into, much less
live in), we believe that safety & structural integrity are better
by using wetted
dirt & allowing it to cure or harden, and ensuring that tangential
pressure as your structure rises doesn't cause your
uncured bags to ooze.
There are no universal "one size fits
all" answers. Your dirt, its clay content, your region's climate
& humidity, your prowess with your
tamper, your speed of construction - all these
& more can impact your results. Let us know your experiences and/or
Check your work in all 3 dimensions... is the course running straight
(end to end)? Are the bags starting to slant inward
(towards you) or outward
(away from you)?
If they are, do you really want them to be doing that?
When building a wall, don't rely on
left-to-right (course) leveling and the back-to-front leveling.
Check the wall itself periodically
with a beam level to see if it's
starting to cant
towards or away from you. If you stay on top of it, you can
self-correct with the next bag
(or, worst case, pull the last tamped
bag & re-do it). Just don't get ahead of yourself.
wire: As mentioned elsewhere, start using 12" - 14" wire
strips between bags if your wall or structure is above 3 feet.
We recommend two strips of barbed wire
After laying a bag, firmly twist the bag to "seat" the barbs
before moving on.
Think of these as reinforcing pillars every 6-10 feet or so along the
length of a wall. Don't underestimate the importance of
of buttressing long, high walls, and
on a plaster / stucco overlay to give such a wall the significant
structural strength you'll
want when the kids are
climbing on it. Rule of thumb for buttresses is 6" perpendicular to
wall for every foot of wall height.
bags: Using these bags
requires working quickly, under dry conditions, and then
plastering them as soon as possible.
It's advisable to utilize a stem wall
them above ground level to prevent moisture from
up. Being willing to work
parameters will reward you with a structure that
is as natural (and as close to true adobe) as you can get.
Because our New Mexico sun is so hard on our polypropylene
materials (UVI, or ultra-violet inhibitor, notwithstanding),
it's a good idea to tarp &
secure your work as
much and as well as possible. Some people spread the work on
bigger structures over
a year or two (also allowing
them to spread
the cost out). Also, some bigger jobs will call for bigger
(allowing for better curves);
remember that we can supply
pre-filled bags up to 3 feet long. On the other hand, we
weather, insects, etc.
any longer than absolutely necessary.
2006 New Mexico Earthen Building
Material Code: click here.