Stage 3: Stem Wall

As mentioned on the Foundation page, frost depth is 90cm. So our stem wall is planned at 1 meter. Each level of bags is about 12-13 cm in height. So we estimated about 8 levels of bags to do until we’re ready to berm.

The first level of bags begins. Until this point, only bookwork, and a few test bags have been done. There’s some nervousness as we start the real thing. But hey, you’re never going to learn if you don’t try. So, we got to work, improvising and improving along the way.

Starting the first layerFirst layer 3/4ths finished

At first, we went with the large coffee can bag-filling method mentioned in the Earthbag textbook. However, we found that things sped up a lot more when we used large plastic buckets instead. They’re heavier, of course, but they cut the transport and fill time in half. We found that with a staff of four people (two mixers/transporters, two bag fillers), we could do one layer, or 28 bags, in about 2 hours. That’s approximately one bag every 9 minutes. Of course, after you get the hang of it, that time drops considerably. Current fill times are just under 5 minutes. But there are other technical factors to contend with, so it comes out even.

After a level is completed, and the last bag fitted in, the bags are compacted with concrete tampers, becoming rock-hard earthen bricks. Of course, hardness varies with soil composition and moisture content. There is a wide range of efficacious soil possibilities. Although you can’t see from the pictures on our first level, it was raining and, correspondingly, our soil was a little soggy. But it compacted well and, once cured, was like rock.

Tamping the first layerWe skipped lunch to get the first layer ironed out. Though a little tired, we are pleased with our accomplishment. 28 bags in all.

First layer complete

The following pictures chronicle our progress as we work up to the one meter mark. First we fix two rows of barbed wire and secure them with bricks. Just as bricks are mortared with cement, earthbags are mortared with barbed wire. It is the glue that unifies the entire structure into one solid mass.

Laying the barbed wire for the second layer

close up of 2nd layer barbed wire prep

Then the second layer of bags goes on, same as the first. On this day, the local children came out to experience earthbag building. It was very unique opportunity for them, and it seemed like they had a lot of fun.

tamping the 2nd layer

On goes the third layer. Notice the difference in thickness before and after tamping.

3rd layer barbed wire prep

3rd row last bag3rd layer completed

And the 4th! Having two baggers made for speedy work on this day. Notice the switch to the big buckets instead of the cans for pouring dirt into the bags.

4th layer halfway

And the 5th layer goes on. We also had two baggers this day. This layer also marked the beginning of the dome. In other words, the radius will gradually be decreasing from this layer on. Of course, this change will be very gradual at first, barely a centimeter per layer.

5th layer 3/4 finishedAnd the 6th layer.

6th layer half way

6th layer 3/4ths complete6th layer complete6th layer complete and restingAnd with that, we actually hit our meter mark. Our bags ended up compacting a little thicker than anticipated. But it’s always good to overestimate. That way you don’t come up short.

Now it’s time to bury, berm and cap the stem wall.


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