construction is the method we chose for the interior walls on our bathrooms. The walls will absorb the heat from the sun during the day, and give it off at night. This is the same concept as the pounded tire interior walls, but the earthbag walls take up a lot less space.
Here are some of the pros and cons of earthbag construction as we see it:
It’s fairly simple. Not a lot of building experience required.
The materials are readily available.
The tools required can be simple hand tools.
The finished wall is quite substantial, unlike a framed wall.
A great wall for thermal storage.
Not real hard to run utilities through, if you plan ahead.
Easy to stucco over.
A lot more work then a framed up wall.
A lot more time to build then a framed wall.
May be slightly more expensive then a framed wall.
It gets a little monotonous filling and stacking bags.
Barbed wire is no fun to work with.
This comparison is between an earthbag wall and a common framed wall. However, there are lots of ways to build interior walls. We looked at several different ways and chose earthbag construction due to it’s lower cost, ease of construction, and thermal storage properties.
Note that this information is for the interior walls we did. Exterior earthbag construction my be a little different, such as the use of a wider bag.
So take a look at how we did it.
Before we started we dug down deeper in the dirt that we were going to pour our slab on to thicken it for the added weight of the walls (a footer). We added extra rebar in the areas in the slab where the walls would set. We poured the footer ourselves and extended rebar to be poured into the main slab for attachment. It’s better to pour it all at once as a continuous slab, you just need to know exactly where the footer is after the pour (1).
Water and Drain Lines, Framing.
The PEX water lines and plumbing vent pipes, which ran buried below ground, came up in some framed plumbing chases in the wall near the fixtures they would connect to. The door framing and plumbing chases were framed up first and anchored to the floor. (2)
Then the earthbags were inserted between the framing (3). The earthbags are staggered on each level so the joints are not in a single line (4). This is the same way that bricks are laid, and makes for a much stronger wall. Staggering the joints was accomplished by adjusting the length of the bags.
Just add the amount of dirt you need to the earthbag to obtain the length you need, fold the excess length of bag over and pin it shut with some nails. Sounds easy, right… not exactly.
Lets take a look at the earthbags we were using to better understand the whole process (5).
We got our earthbags from a company called Uline (www.uline.com). They are just polypropylene sandbags, 12”(30.48cm)wide by 38”(96.52cm) long. The Uline order number is S-13896, but you can find these bags everywhere. These bags will hold 90lbs.(40.82kg) and are very tear resistance. The cost was $59 US for 100 bags (2014).
Prior to putting dirt in the bags the bottom corners were tucked in so they would not stick out when the bags are installed in the wall. The way we filled the bags was one person held the bag up with the bottom resting on the floor, while another person used a plastic coffee container to dump dirt in the bag. Small rocks in the dirt do not matter that much, but I removed the big rocks so I didn’t hit them with the nails when I was shooting them in. The dirt should have some moisture content, but not so much that you end up with muddy hands. Make a small ball of dirt in your hands. If it stays together, and doesn’t stick to your hands, your good. Ours was a bit drier, but worked fine.
We added two coffee containers of dirt to the bag and then gently packed it down with this homemade compact tool. Don’t hard compact the dirt in the bag. Then the bag was laid on it’s side and some nails were inserted into the tucked in corner to hold them in permanently. The bag was lifted and filled further, compacting after each second coffee container load.
Now comes the tricky length operation. The bags are 12”(30.48cm) by 38”(96.52cm) flat. Filled with dirt they become a round tube. When laid down and pounded flat our bags were 10”(25.4cm) wide and 4”(10.16cm) high. This can vary depending on compaction, but we were able to maintain this measurement with not much trouble. The length of the bag is a little harder to figure. When pounded flat the bags can stretch by as much as 5”(12.7cm) for a 27”(68.5cm) long bag. And the shorter the bag you need, the less stretch you’ll get. We got good at figuring just how much compacted dirt we would need to get a certain length (22”(55.8cm) of dirt for a 27”(68.58cm) flattened bag). It’s just a matter of working with the bags to figure out what length they will end up.
After the bag is filled, the remaining bag length is folded over and pinned to the side of the bag with nails (6). Note that even though the bags are 38”(96.52cm) long flat, about the maximum compacted dirt fill you will get into the bag is 22”(55.8cm) and still be able to fold over the top and pin it. Flattened out to 4”(10.16cm) high, this gives a 27”(68.5cm) long earthbag. We found that if you sharpen the nail points and put a little bend in them, they go in a lot easier.
After the bags were pinned shut, they were laid in position and flattened to the 4”(10.16cm) level. When the first level was complete (7), connector plates were added on top of the bags which connect the bag to the door and chases framing. Barbed wire was stapled on top of the plates (8). Plates were added every fourth row after the first. The plates were made of scrap lumber and OSB or plywood. Note the black 6mil plastic and stucco wire on the framing (8). This is for the stucco surface.
Connector Plates, Barbed Wire
Here are some photos that show the connector and barbed wire process (9+).
The large staple pneumatic gun came in handy for the barbed wire, and it should be good for stucco wire (netting) (10). It uses 16 gauge staples, 1”(25.4mm) to 2”(51mm) long with a 1/2”(13mm) wide crown. We used the 2” staples. The gun is a Dewalt D51431 (11).
I took the staple clips apart to hand staple the barbed wire directly to the bags (12-13). The staple gun would have ripped the bags due to the force it exerts inserting the staples.
Add barbed wire between every row. It keeps the rows from slipping apart.
Be aware, barbed wire will cut the living hell out of you! Wear eye protection and do not let the wire spring back on you.
Look at the gloves I used to work with the wire. Use duct tape to prevent cuts, and extend the life of the gloves (14).
Homemade barbed wire gloves (14).
You can do rounded corners with earthbags. Here are some photos of how we did it. (15-17)
On the inside of the bend put some pleats in the side of the bag and pin the pleats with nails. It takes some practice to get the angle right with the right number and length of pleats. It works best to fill, pack, and flatten corner bags in place.
Some tie wires were add every 4th level to hold on metal lath used in the stucco process. Wrap the tie wires around the barbed wire and hung them out (18).