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These construction techniques are chosen because they are low-tech and low-cost. Combined with good quality control, they can create buildings and site structures strong enough to survive hurricanes and resist earthquake damage. Good quality construction includes:

•  plumb and level walls

•  adequate tamping

•  strong bags

•  correct soils

•  appropriate building dimensions

•  maintenance of exterior plaster layers and roofs

These are all necessary to create hazard-resistant buildings. More information on these topics is available at www.earthbagstructures.com.

These details and notes are general and may not apply in all situations. Engineers or expert earthbag builders may be able to make specific recommendations better suited to your site and building.

Earthbag is especially inexpensive if soil can be found on the building site. If you plan your building, you can slope the yard to drain or build a cistern to save rainwater while you are digging enough soil for a small house . It is important to locate the building floor level correctly to allow enough soil to be dug out without leaving low areas that will not drain well.

A single minimal 2.4m x 3.3 m (8' x 11') shelter room can take 8 cubic meters (10 cubic yards) of good subsoil. If it is located on a gentle slope, the ground level may have to be lowered 0.8- 1 m (32 – 29 inches) at the uphill side of a 4m x 5m (13' x 16') area to provide enough soil for this tiny building.

A 3m x 6m (10'x 20') building can take 21 cubic meters (700 cubic feet) of soil. These figures are without buttresses or benches.

In some parts of the world people begin house building with a sturdy cistern beneath the floor. This saves precious space in the cities, and can provide soil for earthbags. But this makes walls higher and requires stronger buildings. To keep earthbag walls strong to resist earthquakes without using a lot of cement, cisterns are best located a meter (3 feet) away from earthbag building walls.

Do soil tests to find out if you have to add sand or clay to your soil. If your soil is rocky, estimate how much of it is rock. You will need to dig up a larger area to get enough soil.

If you have to buy soil for building, some discarded material may be less expensive. Reject sand or ‘crusher fines' are soils left over from making gravel and/ or washed sand sold for concrete work. Test a small amount to see if it will work well for building before you order a truckload.

These figures are for the standard 22 kilogram or 50 pound bags. Adjust for larger or smaller bags.

Bag size: 38 cm wide x 12.5 cm high x 60 cm long, holds almost 30 liters, compacts to 670 cm 2 of wall space when tamped.

15” wide x 5” high x 2' long, holds about a cubic foot, compacts to about 0.70 square foot of wall space when tamped.

Soil is not needed for openings like windows and doors, but about 10% extra is a safe factor to cover mistakes or small changes. Better to have too much than not enough… But for heavy clay soils you should dig up at least 10% more, because clay compacts more than other soils.

If cement and/ or gravel are available you can dig out a cistern to save rainwater and use the soil to build the house. This is how much soil a cistern can provide. (Dimensions are to outside of cistern walls.) Less soil will be left over if earth-filled bags are used to build the walls, more if gravel or rubble from other locations is used to build with:

6000 liter (1600 gal.) cistern yields 6.5 - 12.2 cubic meters (3.8 x 2.3 m, 1.5 m high) or 8.5 - 16 cubic yards ( 12'-6” x 7'-6”, 5' high)

Before building, land may not seem to have a water problem. Rain soaks into the open ground.

After building, rain runs off immediately from the roof, and quickly from the yard. If the earth was made firmer by machines or a lot of people walking, it won't soak up the rain as well. And there will be a lot less of it left uncovered to soak up the rain.

Saving rainwater in a large enough cistern can give you drinking water and help solve damage from runoff problems.

Very flat land can end up with soggy areas that breed mosquitoes. Very steep land can have streams that run into your house or wear away at your walls.

Buildings resist earthquakes best if the ground level floors do not step up or down.

They also resist earthquakes best if they do not have a lot of soil heaped up against the building walls. To be safe in earthquakes it is better to dig some soil out of the higher side of the hill and use a separate wall if necessary.

A house on a slight mound is less likely to have water entering the home. The ground should slope down in all directions for at least 3 m (10'). This slope should be at least 1:50 (1 inch in 4') for rain to run off well. A swale (gently sloping drainage ditch) on the uphill side of the house should start 6 cm (2.5 inches) lower than the level outside the door if it is 3m (10') from the house. Leave enough room for the swale to fit around future buildings or additions.

To get enough soil to build with you will need to dig out more soil on the uphill side. When you choose where the house will go, the floor of the house will need to be a little higher than the ground level on the downhill side. If there is loose rock or rubble nearby, you can use that to fill inside the house to raise the floor level up.

Additional rock or rubble can be used for benches or retaining walls separate from the house.

Materials: Rubble, stone, gravel

Tranchée/ Trench: The bottom of the trench must be level and at least 20 cm (8”) deep on the downhill side of the building. It must be dug down to firm, undisturbed subsoil. The trench must be 45- 50 cm (18- 20”) wide, as wide as the bags and the plaster layers both inside and outside.

Gravier/ Gravel: Use finely crushed rubble or gravel to fill 3 courses of doubled poly bags for a footing.

Sol/ Floor: Fill the interior of the building with rubble or clean fill and earth.

Décombres/ Rubble: Use a 12 - 15 cm thick layer of rocks and pieces of rubble mixed with gravel for the trench footing.

Ouverture/ Opening: Make sure that two courses of bags fit beneath the floor level at the door.

Décombres/ Rubble: Set the floor level 10 cm (4”) below the top of the third course of footing bags. If a concrete floor is added later it will still be below the earthbag walls.

Note: In areas that are subject to frost, the rubble foundation should extend below the frost level.

Materials: Tubular bag, cement, rebar, metal for fasteners.

If reinforced cement footings cannot be used in earthquake prone areas, metal can help to reinforce the wall base.

Sac/ Bag: Earth-filled bags are laid on top of the three footing courses of gravel-filled bags.

Barre/ Rebar: Hammer 35 cm (14”) lengths of rebar into each bag at the second course of earth-filled bags to hold the corrugated strip below in place. Bend the tip of the rebar over.

Bande/ Strip: Place 15- 20 cm (6-8”) wide strips of corrugated metal on the center of the entire first course of earth-filled bags. Overlap strips 30 cm (12”) minimum at ends. Use 7.5 cm nails to pin at overlaps and at corners to the bags below.

Gravier/ Gravel: Three courses of gravel-filled bags will prevent dampness from damaging unstabilized earthbags. If soil is to be backfilled higher against the walls, use enough courses of gravel bags to keep earth-filled bags 15 cm (6”) above finish grade.

Materials: Bags and/ or tubes, gravel, cement, #4 (1/2”) minimum rebar, galvanized metal mesh, poly or nylon fishnet, latex waterproofing, pipes, strong poly or nylon cord, and lid.

Locate any cistern 1 m (3') or more from any proposed building walls. Be careful to not disturb the soil where the building will be placed.

These designs are only intended for frost-free climates.

Left: Cross-sectional view

Bags filled with only earth are not recommended for underground use. They can be damaged by high water levels or by leaking from the cistern itself. This can cause the walls to fail.

The first 3/4 meter (30”) can be built with bags filled with angular gravel if it interlocks well enough to be stable. Bag and test your gravel to be sure. The upper courses must be filled with rubble or gravel mixed with a slurry of cement, or earth mixed with enough cement to fully stabilize it.

The curving top is built of ferro-cement tied to a thick interior cement plaster reinforced with mesh.

Left: Use a pole compass to build round walls

Pound a 60- 90 cm (24- 36”) pipe into the ground at the center of the cistern location. Put a 1.6 m (5'-3”) height round stake or smaller pipe inside. This must be perfectly plumb. Slide a pipe clamp or clip onto the stake. This will be adjusted to the height of the bag course you are measuring. Then add a ring or a short piece of pipe above it. Tie a sturdy rope or fasten a metal arm to this moveable ring or piece of pipe.

Note: Provide bracing if necessary until the cement plaster interior is completed.

Sac/ Bag: Doubled poly bags filled with gravel. Angle bag ends to center of dome to accommodate curve. Fasten interior layer of metal mesh to exterior layer of fishnet every 2 courses and 60 cm (24”) horizontal.

Fil de Fer/ Wire: Use 2 rows of barbed wire between each layer.

Tube/ Tube: Tubes or bags filled with stabilized earth or with gravel or rubble in a cement slurry. Test to find the best ratio of cement and/ or lime needed for your fill material.

Terre/ Soil: Place bag walls on undisturbed subsoil.

Barre/ Rebar: Hammer rebar for ferro-cement framework through upper courses of bags or tubes before cement sets.

Ciment/ Cement: Bend vertical rebar and wire horizontal rebar to it to form top. Attach mesh for top following best practices for ferro-cement. Place reinforcement of mesh or rebar for tank floor.

Add rough cement plaster to exterior.

Bâtiment/ Building: A cistern should be located at least 1m (3 feet) from an earthbag building wall.

Pipe/ Pipe: Build a ferro-cement pipe with an overflow spout, sloping up from the tank to 30 cm (12”) above grade. This pipe must be larger than the gutter downspout, and be screened. Add a second pipe for a water supply line.

Citerne/ Cistern: The cistern walls and roof must be backfilled and covered.

Trappe/ Hatch: Provide a hatch of 2.5 cm (1”) thick cast concrete or heavy metal that overhangs the scuttle beneath it. The hatch should be at least 30 cm (12”) above grade to prevent contamination of the stored water.

Do not backfill until ferro-cement structure has completely cured. Use scrap cardboard or straw to protect bags from damage if backfill material contains rocks.

Note: Locate overflow spout above stone water spreader in swale.

Bâtiment/ Building: A cistern should be located at least 1m (3 feet) from an earthbag building wall.

Pipe/ Pipe: Build a ferro-cement pipe with an overflow spout, sloping up from the tank to 30 cm (12”) above grade. This pipe must be larger than the gutter downspout, and be screened. Add a second pipe for a water supply line.

Citerne/ Cistern: The cistern walls and roof must be backfilled and covered. This oval cistern will be stronger if the straight wall section includes a pier on each side.

Trappe/ Hatch: Provide a hatch of 2.5 cm (1”) thick cast concrete or heavy metal that overhangs the scuttle beneath it. The hatch should be at least 30 cm (12”) above grade to prevent contamination of the stored water.

Do not backfill until ferro-cement structure has completely cured. Use scrap cardboard or straw to protect bags from damage if backfill material contains rocks.

Locate overflow spout above stone water spreader in swale.