Why should 'I' use Earthbag ?

SUSTAINABLE

Energy efficiency is a strong plus in favor of building with bags. The massive earth walls stabilize interior temperatures in hot climates. In cold and hot climates, earthbags can be filled with an insulating material, such as lava rock, pumice, vermiculite or perlite. Some builders are experimenting with rice hulls for insulation, which are often free for the taking. In general, lightweight insulating materials (such as those just mentioned) require far less labor than those of tamped earth and provide comfort through the harshest winters or hottest summers.
Earthbag buildings are sustainable since they are made primarily of earth from or near the building site. Earthbag domes do not require wood, thereby reducing pressure on our forests. Expensive concrete foundations are not required if you use gravel-filled bags. In addition, these structures are safe, quiet, nontoxic, rodent proof, and fire, hurricane and flood resistant.

SIMPLE

Earthbags are ideal for owner-builders. The necessary skills for each step of construction can be learned in a few minutes. It boils down to simply filling bags with an appropriate fill material (typically subsoil or gravel) and tamping them solid. It doesn't get much simpler than that. Also, few tools are required - shovels, buckets, garden hose. The few additional tools needed (tamper, slider) can be made cheaply and easily.
Earthbag building can be designed to suit a wide variety of climates. Since the woven polypropylene bags are virtually rot proof, earthbags are an excellent choice for underground structures: root cellars, storm shelters, bermed homes and greenhouses. In climates where wood is scarce, whole houses can be built exclusively with earthbags including the foundation and roof, as is the case for corbelled earthbag domes. Earthbags also combine well with other natural building materials that can be combined together to create hybrid structures. Straw bales can be interlocked with earthbags to build sturdy arch entryways or to add thermal mass to the interior wall of an attached sunroom. Or we may choose to use earthbags for the sunken first level of a structure and then switch to strawbale, post-and-beam, cob or adobe brick for the rest of the wall above grade to make use of an available resource or add aesthetic variety.

AFFORDABLE

Earthbag is surely one of the lowest cost, most practical building methods. It has the advantage of being able to use a wider range of filling materials. A simple earthbag dome, for example, using recycled grain bags and earth can be built for around US$100. A larger, more comfortable home can be built for around US$500-1000. It is more durable than tarps and more comfortable than tents, earthbags work perfectly since even unskilled workers can build their own shelters - all without destroying local resources.

Roof Construction

Having taken such a natural approach to our wall construction, it only seemed logical to incorporate this approach into the design of our roof. The roof can be the cause of great internal heat loss in winter and rising temperatures in summer from the penetrating sun rays.

Traditionally a conventional roof system is put in place with insulation batts to improve thermal efficiency. However our approach was to use a fairly new a currently uncommon method of Green Roofing.

Environmental Advantages of Green Roofing

Reduce Urban Heat Island Effect (UHIE):

Built up urban areas experience increased temperature during warmer months, compared to rural areas. One of the major culprits are Commercial Office buildings, whose construction materials consist largely of glass, steel and concrete – most of which have high thermal mass properties, meaning they heat up and re-radiate heat back into the atmosphere during the night.

Green roofs can help lower ambient air temperatures. Studies have shown that temperatures in built up areas can be reduced by up to 2 Degrees Celsius if just 8% of buildings have green roofs.

Storm water management:
One of the more significant problems facing Melbourne is its underground storm water infrastructure and capacity to service the city’s growing development. Green roofs reduce storm water volume and calm water flow, thus helping to ease the pressure on storm water infrastructure.

Green roofs also filter and cool water runoff. They can help prevent nitrogen, phosphorus and toxins from entering waterways.

Sketch(up)s V03! - Final Wall

Some tweaks to make the wall a bit less wide.

VERSION 03 - Final

Still retaining an air gap, but letting the earthbags do the work on their own. This allows for only 1 stud frame.

Profile depth - 400- 460mm. (will depend on how wide we want the air gap (40-100mm)

Thoughts - A reduced profile makes for a more usable wall. Think we are on the money with this now.

What now?

Well we have the Earthbags filled and the frame constructed. So we now need to identify what we still need to complete the wall, and start putting all the elements together. Still required:
- Window frame
- Window glass*
- Plasterboard
- Render*
- Wire mesh
- Flashing
- Foil

Then we need to look at the roof!...

Build Day 01 - Videos

Along with the Photo diary we are keeping, we have taken a selection of short videos to explain and show in a bit of detail some of the processes involved in creating the Earthbag wall.

VIDEO DIARY:

Earthbag - Sourcing the Soil:  Joel explains what Dan is up to loosening the dirt and gravel with a pick.

Earthbag - Filling the bags:  Dan explains what Joel and Leah are doing.



Earthbag - Stacking the bags: Joel explains how the team intends to put the earthbags together.



Earthbag - Preparing the Frame:  Dan cuts some of the timber for the frame to length.



Earthbag - Building the Frame: Shakiba nailing together the frame ready.

Frame complete and bags filled, construction to begin very soon.

Build Day 01 - Photo Diary

The group has been quite busy with life in general over the last few weeks, so getting the blog posts up haven't been highest on the list of priorities.  Unfortunately its taken almost a month to put up one of the more important posts.  Build Day 01!

With Build Day 02 quickly approaching, its important for us to show how much we have done so far.  With the design 80% locked in when we began the day (16th April) we headed to Bunnings to pick up a few items we would require to begin the build.

PHOTO DIARY:

Before any shopping could begin Joel introduced Shakiba, Leah and Bao to their first ever Bunnings Sausage Sizzle. YUM!!

Leaving Dan to scout ahead and find some of the timber we needed for the frame.

After about 30minutes we'd picked up the required timber, nails and other items we were short on and headed to Dan's house.

Some quick discussion of who would shovel and who would hold bags we started filling up our earthbags with sand and a rock/dirt combination.  Leah & Joel filling some rock/dirt bags.

Dan & Bao filling up some of the sand earthbags.

After filling up a bunch of full and half full earthbags we put them aside and started looking at our wood framing.

Dan, cutting to size some of the studs.

Frame starting to take shape with studs and top and bottom plate cut to size.

Frame pieces all cut to size and placed together, just needs some nails now.

Bao & Shakiba tapping away with the hammer.

And the finished frame.

So after Build Day 01, we have all of our earthbags filled, and our main frame created.  Build Day 02 we will focus on putting the earthbags into a wall supported by the timber frame behind.  

Video: Video's of this Build Day will be posted in a separate post shortly.