Ok, with these unorthodox building materials it seems that you learn as you go: The mesh tubing wasn't working out quite the way I'd hoped. The bottles tended to shift inside the tube so that they wouldn't lay flat once they were moved. Also there were substantial gaps in between the top of one bottle and the bottom of the other. I needed something that would insulate better and that was easier to work with and construct. So I thought and experimented, thought some more and experimented some more, and finally I think I have it! The building process is as follows:

1. I created a 4' x 2' 4" wooden frame to keep the bottles aligned while making an insulation panel.
2. I lay a 3' x 8 1/2' sheet of 4 mil plastic sheeting in the bottom of the frame with the overlap hanging out.
3. 66 bottles fit inside the frame and I use spray adhesive to stick them to the bottom plastic as I insert them.
4. Plastic bags are stuffed between any gaps such as the gap around the cap of the bottles
5. The tops of the bottles are sprayed with adhesive and then the sheeting is folded over, sealing the bottles within.

The picture below shows the bottles in the frame.

The resulting panels are uniform, light and easy to handle. They will be tied to the earthbags and then covered with either hardware cloth for plastering or an additional waterproofing layer. I also believe that these panels will be much better at insulating the walls than the mesh bags. Who knows though: I may be changing the plan again!

Well, the school year is finished and therefore so is my collection period for water bottles. By estimation I have approximately 6,000 bottles to show for a little over 2 months. I could never have come close to that number without major assistance from faculty members, parents and students! Thank you all!

As impressive as that number is it is still less than half of what I needed for the original plan. With the 6,000 bottles I had two options (I don't have time for continued collection). I could have covered half the wall in the bottle blocks and used another method for the other half or change the arrangement of the bottles to allow for full coverage with lowered insulation value. As this cabin will mainly be a three season retreat, I opted to reorganize the bottles. I can always add more insulation later if needed.

The new plan is to take the bottles and attach them end to end in long rows. The long rows are fastened together with plastic wrapping and then they are inserted into the same mesh tubing that we will be using to build with (I should have plenty of extra). See the picture below but imagine the bottles in an eight foot tube.

This will considerably reduce the R-value (insulation value) since we are going to be laying the bottles against the side of the wall instead of pointing them out. The insulation thickness goes from 6+ inches of plastic and foam down to about 2.5 inches (the width of a bottle). Oh well.

There are some benefits to this method though. One, the use of the foam is no longer necessary so the cost goes down and the insulation becomes "greener." Two the mesh bags will allow better adherence of the plaster which will eventually cover the walls. All in all I feel very good about what we have done. 6,000 bottles and 18,000+ plastic bags out of the waste stream or without the energy costs of recycling is nothing to sneeze at! Keep checking back to see how things are shaping up.

We have gotten our second estimate or preparing the land for building and it is much more reasonable. Sometimes things just have a way of working out and this newest development is further evidence of that. While we were up logging the land a neighbor of ours stopped down to have a chat. He mentioned the name of an independent contractor, S. E. Rodich Excavations, which did road work for the community and also some side jobs for residents. Well we took his advice and Rodich came back with an estimate that was one third the cost of the first! Needless to say we are going with him. 
We also happened to mention to this same neighbor that we had a lot of trees still to cut down and he mentioned that he was in desperate need of firewood. With more than enough wood on our property we struck up a deal. I recently returned from a fishing trip and visit to the property and was pleased to see that not only were the trees that we needed cut down gone but that a simple cleared driveway had been pushed in to help haul out the lumber. This drive is quite useful for us for moving supplies in and out and general access of the site. Things are looking up!

The following link directs to a builder named Jesse Loving that is creating an earthbag house in Belize. The design involves a central courtyard with a doughnut shaped house surrounding it. This is a truly amazing structure and much more complicated that the design that we are going to build. Also different is the fact that they are using the traditional poly earthbags while we will be using the hyperadobe method with mesh tubing. Still, there is a lot to learn from Jesse's project. The gravel foundation and infill will be the same method that we are going to employ and the straight lintels above the exterior windows will be something that I hope to emulate. Additionally this is a round structure just like our plan, except ours lacks the courtyard. Check it out if you are interested in this building method. His albums are a terrific visualization aid for earthbag construction.

Jesse Loving's Picassa Album

So we got our estimation back from the first excavation company and unfortunately they quadrupled our projections. I won't post their name but I found their prices beyond reason. The following is what we had required:

1. Clear and level a 50' x 50' area (tearing up stumps and moving to the side of the property)
2. Dig a 2' wide x 2' deep foundation trench in a 100' circumference circle
3. Put in a 10' x 20' gravel driveway.
4. Deliver 40 cubic yards of compactable soil and 18 cubic yards of stone.

As I previously wrote the land is rather sloped and that accounts for some of the cost. Also the delivery of that large an amount of soil and stone requires arrangements to be made for the large trucks to move onto the property. Still the cost of those materials was outrageous. Quality soil is generally around $20 - $30 a yard. Their cost was around $70. Stone is somewhere around $40 a yard around here. Their price was close to $122! We did not deal with this company on burying the rear of the cabin in the slope since this initial estimate came back so high. 

Unfortunately this highlights the cost of doing business in remote areas. There are less qualified companies available for labor and the delivery of common building materials can be expensive or impossible. We have another private contractor to get an estimate from on May 7th. We'll see what happens but since he is an individual rather than a company I expect a much cheaper quote. Also we are going to contract the soil and stone separately from the excavation. I post those results.

Last weekend three of us took a trip up to the land to do some cutting and clearing. We began with a densely wooded and overgrown patch and after two days of work ended up with a fairly clear 50' x 50' area. I say fairly clear due to the fact that a giant granddaddy of a triple trunk tree is left smack dab in the middle of the site. This monster must be 110'+ and it splits into what would be three fairly large size trees on their own You can see it in the picture above on the left side of the clearing. Obviously they have to come down but we just ran out of steam.
The plan is for a 30' diameter roundhouse, so 50' gives us about ten feet clear all around. The trouble with the piece of land we are working on is that it steadily slopes to the back of the property giving us very little working room. Regulations state that the building must be 100' from the road and we are currently at 90'. We therefore need to push the cabin back but are faced with some substantial sloping the further from the road we travel.
We are looking into two options right now to tackle this problem:

1. We spend the money to have an excavator build up and level the site toward the back.
2. We spend the money to have an excavator dig a semicircle down into the slope thereby burying the back of the cabin and leveling out to the front. I've made some models of this using Google Sketchup and Skitch for labeling.

Either way... we spend the money. Ugh! At this point though I'm hoping to go with option 2. This way we can leave the property behind the cabin still fairly natural and make the cabin less noticeable from the road. Also earth sheltering helps to moderate indoor temperatures due to the fact that the ground tends to remain a fairly constant temp a few feet below the surface. This helps even out heating and cooling requirements even more. The problem of course would be with managing the moisture but we've got a pretty solid plan of how to deal with that. If we decide to go this route I'll definitely do a post on it.

I have been playing around with the idea of using hyperadobe building method rather than earthbags for a few months now but I am facing a supply problem. Hyperadobe is a building method that is a relatively recent find by alternative builders. As a constuction method it is similar to earthbags that I have described but the retaining material for the soil is different. Instead of slippery poly bags, hyperadobe uses a strong mesh tubing similar to what is used in produce packaging for onions or potatoes or erosion control booms. The tubing is filled with soil and tamped down solid just like earthbags but each course has greater adhesion to the course below due to the mesh openings. The dirt becomes a monolithic structure and achieves great stability with less effort. The most appropriate tubing material in the US that I have found is called Raschel Mesh or Leno Mesh. The Leno Mesh is pictured above. 

The difficulty I am facing now is where to purchase the materials. Since the material is so thin and lightweight it comes in lengths between 1000' to 3000' which is more than enough to build one cabin of the size that I am planning. However, most manufacturers of these types of tubes will only deal in large quantities like shipping containers or skids. And the few suppliers that I have found are imposing a huge markup on the products. For example, a manufacturer of erosion control booms in Canada lists the product at $300 - $350 per roll, while their supplier wants double that.

If you have any leads on where I might purchase the type of material pictured or listed above please leave me a clue in the comments. Thanks!

Craigslist is my best friend! For the cabin I am attempting to either build or purchase second-hand all of our necessary materials. Again this is making our cabin not only cost efficient but also environmentally sound. It is amazing how many serviceable and good quality items are replaced by homeowners and builders. The saddest part is that these items are often not replaced for lack of functionality but rather for aesthetics. And the aesthetics could conceivably be achieved with just a little elbow grease. The following list details the items that I have already purchased and the price I paid for each:

• 20 small double-hung, double-paned, vinyl windows: $10 each. These windows were picked up from a window dealer as models yet they are fully functional. (There may be a trade off in efficiency versus more modern windows, yet the small size and the other thermal properties of the building help to offset this.)
• 1 Steel Exterior Door: $50.  This door was replaced after a few years of use with a fancier design. It came prehung and predrilled. At this point it needs a coat of paint and a knob/lockset.
• 175 feet of flexible drain pipe: $50. This pipe will be used to construct a french drain at the foundation of our cabin. We needed 150 feet approximately but it is always good to have a little extra. This was purchased from a landscaper that had some left over from a job. New price is usually $1 a foot.
• Bathroom Sink, Base Cabinet, Mirrored Medicine Cabinet: $30. Completely functional and well maintained set. This was purchased from a person "flipping" a house and upgrading the kitchen and bath. It is tiny but perfect for the tiny bathroom that we have planned.

An inherent quality of building with earth is the tendancy of the material to resist rapid changes in temperature. Cold earth wants to stay cold while warm earth wants to stay warm. It takes a great deal of energy to force the temperature shift in one direction or another. However, once you have, it will stay that way for quite some time. This can be both a benefit and a curse depending on the prevailing climate.

Our cabin will be mainly used in the spring and summer but there will be times that we need it during the colder months. In the mountains of Pennsylvania this cold can be quite extreme. In an uninsulated earth cabin we would be faced with a constant need to burn fuel for heat as our interior temperatures attempted to win out over the prevailing exterior temperatures. Two solutions are possible for this problem. The first involves filling the bags themselves with insulation such as scoria, vermiculite, rice hulls, etc. The second involves insulating the outside of the earth structure. Thereby seperating the two temperature extremes and allowing the walls to retain their heat longer. There is a great blog post and related instructable created by Dr. Owen Geiger on this process.

We will be using the exterior insulation method since scoria (lava rock) is rather expensive here in PA and lightweight insulators like perlite would require a wooden frame of some sort. Our unique insulation will be mainly built out of plastic "trash". Specifically, massive amounts of plastic drink bottles and plastic shopping bags are the prime materials. The basic process is outlined below:

1. Stuff a 16 - 20 oz. plastic bottle full with plastic bags (usually 3-4) and screw the cap back on.
2. 20-25 of these stuffed bottles are squeezed tightly into a form. I use a milk crate-style container with the bottom cut out.
3. Squeeze small amounts of expanding spray foam in between the gaps of the bottles. If you have compacted the bottles enough in the form this doesn't take much. Also I use the Great Stuff Big Gap Expanding Foam which really fills the space well.
4. Allow the foam to finish expanding and setting and then remove the "brick" from the form. See the photo below.
5. These bricks can then be mortared together with a natural soil based mortar.

The plastic bricks will be attached to the walls with nylon twine and covered over with plaster. This design reuses thousands of bottles and bags and I hope that it will do an adequate job insulating the walls. The entire job is a lot of work! Collecting the materials alone is a huge job. Luckily for me I am a school teacher and everyone (faculty, students, and the families) at two of our district schools is being such a help and support. I even have my eco-conscious students voluntarily giving up recess to help me stuff bottles full. Certainly without this help I would never be able to do it.