The mass wall of the earthship did not survive the Tennessee winter mud season. I covered it as best as I could but there was just no way to keep all the water out. Where the water got into the wall, it slumped and began leaning forward into the building and became unusable as a building component. I believe if I would have amended the soil with sand and lime and installed it into the bags with a more consistent moisture content, it would have worked out better. I've also discovered that I did in fact order non UV treated bags. I had no choice but to take it down as it was making me nervous just to stand near it.
The failure of this building was a large time sink and direction change for the project as a whole. I've been hesitant to release the video partly because I wanted to have a more clear direction of what I was going to do moving forward and also this video was made during a stressful time of uncertainty and does not reflect my usual optimism.
Unfortunately, I do not have the resources (time,money) to put into another experimental building. Since the making of this video, I have pushed the mass wall into the ditch to form a dam wall with a fairly large body of water. I re-graded the site and have concrete forms up for a pre-fab steel shell building which will be well insulated and have radiant floors fed by solar water heating panels and will still incorporate the cooltubes and a solar chimney effect with clerestory vent windows. I may revisit being off grid with electric power at some point in the future.
In this part I talk about the landscaping and the back berm, show the progress on the mass wall, explain the foam and vapor barrier, describe the bond beam and banding, water and moisture control, and some future aesthetics.
I have the metal straps which will hold the bond beam down installed with a course of bag over them. The roof logs will be attached to the bond beam and the straps will prevent the roof from coming off in a major wind event. I also show the final course of foam insulation installed and talk about the method I've been using for "easing" the weight of the dirt onto the foam. I discuss the materials and methods for dealing with the vapor barrier. I show the excavation and the front yard taking shape and discuss the importance of having access to machinery.
Some pics and an update. I'm up to the course of bags where I need to start putting in the hardware for the bond beam which ended up being at 7'. I'm going with stainless banding wrapped around the last 2'6" of bag wall to hold the bond beam down. This is important because the roof will be attached to the bond beam which will hold the roof down in the event of a major wind storm.
The 300% rain that we received here in Tennessee this summer finally dried out enough where I was able to finish burying the cooltubes out into the forest. It turned out to be fairly labor intensive the way I did it as I was unable to use a machine to bury the tubes directly. The clearing I had made in the forest for the ditch was fairly well surrounded by trees making it impossible to get my backhoe in there. Also, the ditch was only 3-4' deep which required me to be very particular about getting the fill directly in contact with the tubes just right to maximize heat the transfer from the tubes to the earth.
There is no "industry standard" as yet for the installation of this system. I had to take into consideration the soil type, topography, available equipment, and budget to design my earth air heat exchange system based on the knowledge available to me at the time. I put the tubes 3-4' underground and had them exit the ground horizontally to maximize drainage. The fall in elevation from where they exit the house is 15' which made me decide use a solid, non perforated pipe as any water due to condensation would drain out of the downhill end eliminating the need for a perforated pipe. I did not want to use perforated pipe as the holes are an entry point for underground moisture. With the solid pipe making any condensation drain out only at the end of the pipe, there is no need for gravel in the ditch around the tubes. The dry-ish crumbly clay I packed around the tubes has much more surface area than gravel maximizing the contact with and heat exchange from the air through the wall of the tubes and into the earth.
Dirt has .1R value per 1 inch. I buried 2" of white beadboard insulation (the cheap stuff) on top of the 6" of dirt on top of the tubes. So the math: 2" of insulation at 5R value per inch= 10 Rvalue/.1 Rvalue per inch of dirt = 100"/12 = 8.3'+3'deep burial = 11.3' deep
I thought about and researched what bag material would be the best to use and what would be the easiest way to fill it with minimal help. Most of what I saw on the internet for earthbag building was a large group of hippies with coffee cans filling earthbags (in my opinion) very slowly or people using various stands to hold open and fill individual bags and place them one at a time. Neither one of these options would work for me as I have only a few people helping me and the idea of lifting and placing individual bags for a wall that will be 130' long x 2' wide x 10' tall seemed impossible. I decided to go with woven polypropylene rolls which I got in four 1000' rolls. I had to make my own invention for loading up to 70' of tubing on, holding it up for filling and releasing the filled bag into a form. I will be a bit vague as to the exact specs for building the thing as I may offer a set of plans for sale if there is any interest.
In my travels on the internet, I tried to find an industry standard working model for installing a ground coupled heat exchanger that I could copy and found that it doesn't exist. Everyone seems to have a different opinion on how this system should operate which led me to the conclusion that the design is very site specific.
In my situation, I have a hot, humid climate that I most need to mitigate, a limited budget, a bulldozer, fairly easy to dig clay subsoil, much slope in all directions (both away from the house and towards), all connected to a home which will be off grid and will not have the power required to run a dehumidifier at night.
I went with 6" non perforated corrugated flexible pipe and chose to bury them 170' from the house. From various studies, you get diminishing returns after 130' so this should be adequate. There is 20' of drop from the house so I am not concerned with the pipes not draining properly. I used corrugated because in the flat walled pipe, the air separates into layers and a slow moving layer forms on the inner surface of the pipe and the hot, humid air flows through that layer of slower moving air directly into the home. The goal of this system is to have as much of the air as possible come into contact with the inner surface of the pipe which is directly in contact with the ground to create the greatest amount of heat and humidity transfer so a bumpy inner wall over distance helps this process .
The wall is up to the second course of bags and the first course of foam insulation with vapor barrier is up. In the video, I discuss the geotextile and where I plan to run the cooltubes.
Now that the farm is running nicely, fencing done, pigs trained, chickens ducks turkeys and rabbits doing well, it's time to work on the house again. In this video, I show the installation of the rubble trench foundation and the geotextile which will make the main mass wall of the house monolithic and explain why that is a good thing. I talk about the method for filling the earthbags (which is now somewhat different and better) and show the materials used in building an earthbag earthship with no concrete, which is likely the first earthship style building to be done this way. Credit for the engineering and innovative design ideas must be given to the Architect, Howard Switzer from earthandstraw.com
In today's post I talk about logging, hugelkultur, putting wood on the downhill side of a swale mound, build site leveling, and road building.