Timeline - Amount of Earth Sheltering and Configuration of Earth Contact Walls

Fits and Starts over Past Eight Years

Decision on Amount of Earth Sheltering

Our original intention was to heed the advice of Hiat, Stephens and Carmondy/Sterling and earth shelter as much of the house as was practical for our site.  Accordingly, the north wall, the north half of the roof and most of the west wall would be sheltered. The 
east wall would remain mostly unsheltered because it was an attached garage and entryway.  According to the prevalent philosophy on earth sheltering, maximizing the amount of earth contact would benefit the thermal performance of the house in two ways --  by increasing the size of the thermal mass and decreasing the amount of the envelope exposed to the environment.  Less exposure means fewer opportunities for air infiltration and fewer walls needing conventional insulation.

Green roof and earth contact west wall (all concrete)

As recently as last year, after our engineer had produced the first set of drawings, based on my amateur drawings and a model of the house, it became apparent that earth on the roof was not doable because the timber frame to support it would be too expensive.  And, in the absence of a concrete roof, there was always the issue of termites.  However, the amount of earth sheltering for the west wall remained in flux until the final construction drawings when it was reduced by one-half in order to reduce cost and simplify construction.

Earth Contact Walls in Conjunction with AGS

The only practical option for earth contact walls is concrete of some sort.  If an earth contact wall is continuous with earth on the roof, as advocated for AGS (see second post on AGS) the entire wall is protected by the insulation-watershed umbrella and could remain uninsulated.  However, in our case, at least 8" of the top of the wall will be exposed below the roof (for termite protection).  So part of the wall has to be insulated and part not, creating two zones.  The bottom zone is uninsulated so heat can move freely back and forth through the wall as part of the AGS system.  The top zone is insulated and starts a foot or so under the level of the insulation that lies horizontally as part of the insulation-watershed umbrella and it ends at the roof line.

Upper area of back wall is insulated (black); lower wall is not (brown)

Advantage of a Two-Story House
Fortunately, our two-story house will have a tall back wall.  This allows for an uninsulated zone almost as large as the back wall of a typical single story with earth on its roof which should make the AGS system just a functional as the pure design Stephens advocated. The biggest challenge will be to create stick built exterior walls and a conventional roof that will not waste the precious heat after the system produces it. However, as I will detail in a separate posts, the 15" thick truss walls and 16" deep cathedral ceilings filled with rice hull insulation will more than compensate for the lack of earth contact on the east and west walls.

Complete Block System

In order to reduce costs, the design of the concrete walls went through several iterations ranging from DIY poured concrete to DIY dry-stacked cinder blocks to a new system called "Complete Blocks" (Complete Block Company) to professionally poured concrete. The most ideal solution would have been the Complete Block System in that its precision concrete blocks come both insulated and uninsulated so they could be mixed and matched as necessary to satisfy the two zones.  However, the cost was budget-busting and the test data the start-up company was able to provide for our structural engineer was insufficient. So we went to plan B -- professionally poured uninsulated concrete.

Odds 'N Ends - Carbon, Global Warming and Native Plants

Succinct Description

Wild Ones is a national organization that promotes landscaping with native plants.   A succinct description of the carbon cycle, which under-girds any environmental discussion, appears in the March/April, 2014 issue of the Wild Ones Journal.  The author, Daniel Kjar, PhD, Myrmecology, Ecology & Evolution, had this to say:

"Carbon is an element that makes up both plant and animal life on Earth.  Carbon is the backbone for most if not all organic molecules.  Through a process called "photosynthesis" that only plants can do, they use the sun's energy to combine carbon, oxygen and hydrogen to make glucose, a simple sugar.  Every other living thing utilizes the sugar molecules manufactured by plants to obtain the carbon for whatever is needed.  We humans convert the sugar into fats, proteins, nucleic acids and numerous substances that make up our bodies.  This cycle of carbon can be represented as:

Energy from sunlight + carbon dioxide + water  ->  sugar  ->   carbon dioxide + water + energy of life."

(I guess it is safe to say that some animals exist on plants (herbivores), some exist on animals that exist on plants (carnivores) and the rest exist on both (omnivores).)

Fossil Fuels  

He goes on to say that, "Organic matter.....can slowly turn into long chain carbons......that we use as fossil fuels.  The burning of fossil products that we mine from the ground.......releases far too much carbon into our atmosphere, creating the Greenhouse Effect that is heating our atmosphere."

Global Warming Controversy

When Darwin introduced natural selection, the reaction to it took several contentious decades to work through three stages that all profound truths seem to have to go through -- ridicule, opposition and acceptance -- while financial interests confuse, delay and deceive.  Do you see a parallel for global warming?

Native Plants

Native plants not only produce food for wildlife, but, by mitigating global warming, make the planet a healthier place to live.  They are easy on finite resources in that they do not need watering (water is becoming the world's most valuable finite resource) or fertilizing or mowing (both of which require the finite resource -- petroleum).  Native plants had been doing a good job of sequestering carbon for 20 million years until the Europeans came to plow them under, cut them down and burn them off.

If you have any interest in natural landscapes,  we heartily recommend becoming a "Wild Ones" member as an opportunity for networking, sharing information and exchanging seeds.  We have already started using natives for the landscaping we can do before construction is finished and plan to maximize native landscaping post-construction. Fortunately, we will be able to tap into the broad expertise of the more knowledgeable fellow members of Wild Ones.

Construction - At last!

Straw bales for silt fence

Today is August 3, 2014 and we are finally beginning construction. The straw bale silt fence is in place and excavation has begun.

Dry Season
In Collinsville, it has not rained in over a month although some of our neighboring communities have been more fortunate.   

Silt fence on the east (close-by) and the south (downhill)

We have been hauling water from home 
to fill the 2 gal containers (discussion about water containers) that keep new trees and bushes watered as well as critical plants in the garden such as tomatoes, okra and squash.  And the dry season has limited the amount of mowing necessary, thank goodness.

However, as discussed in the posts about the excavation plan, Excavation and Excavation (Cont'd),  the dryness has allowed us to begin construction sooner.  Based upon the soil cores taken when the piezometers were installed, the concern was that too much moisture in the deeper silt soils or a torrential downpour on the excavation after the organic material was removed would be too difficult for a DIYer to manage for reasons explained in the posts on excavation.

The first bucketful!

Excavation -- First Day
I developed a few track loader skills while doing dirt work at my step-son, Keith's, owner-builder project. Today, I find them to be a little rusty after the layoff of a year.  However, they not only came back after the first couple of hours but I gradually added efficiency. 

The goal is to create first a north-south profile of the excavation about 15' wide just east of the footprint of the house that will accomplish two purposes.  The first will be to provide a ramp in and out of the excavation for carrying the soil for storage on the flat area north of the building site.  The second goal is to validate the elevation for the eventual floor before actually carrying the excavation westward into the footprint of the house.  

First half days worth of hard digging

Hardpan
The ground is so dry that I have spent an inordinate amount of time with the toothed bucket on the loader trying to penetrate and separate the topsoil from the soils below for separate storage.  As I continued deeper, the soil below the topsoil was also bone dry and hard to pry loose down to a depth of four feet or so.  (Makes one wonder how shallow-rooted trees survive in droughty periods.)   Below that, digging was what I would consider normal for compacted soil.

Unexpected Debris
The area of the first dig was once the site of a very large barn, according to the sons of the original owner.  Supposedly, the foundation was removed and the cavity closed with fill dirt.  Sure enough, below the topsoil I encountered a layer of clayey soil with numerous bricks and stones to a depth corresponding to the frost line.   And an iron pipe, presumably a water pipe leading from the house, added to the fun.  As is apparent in the accompanying photo, the silt topsoil in the near pile has a different color than  the underlying soil in the far pile (click on the image for a clearer view).  

Second Day -- Not so good
After 10-12 bucketfuls, the loader stopped dead -- seemingly with no power from the battery.  Most of the day was spent solving the problem because my mechanical skills are almost non-existent and it wasn't until Keith, with his  trouble-shooting abilities, came to the rescue that the problem was fixed.  Although it was not the cause of the problem, we found a fuse-link that should be replaced before the jury-rigged, "penny-behind-the-fuse", situation had a chance to cause a fire.  An opportunity to upgrade the track loader at this early juncture is a good trade-off for the loss of a few hours of digging time.

Design - Excavation (Cont'd)

This post was written at an early planning stage whereby I intended to minimize cost by doing most of the work myself.  When it came time actually to do the trenches for the French drains and the AGS conduits, we were in the midst of the rainiest Spring in history. It became necessary to get as much work done as possible between rains so we enlisted professional help for the trenching as well as for grading for the slab floor.   It took several posts to cover the installation of the French drains and AGS conduits. Here are links to those posts:  First post on French drains, Second post on French drains, Last post on French drains,  First post on AGS system, 

French Drains
The typical French drain is a trench about a foot square in cross-section with a perforated drain pipe it it.  The pipe is laid on a 2" bed of coarse gravel then the trench is filled to the top with more gravel.  Usually, a "sock" made of geotextile fabric surrounds the pipe.  The same fabric completely lines the trench before any gravel goes in, then is folded across the top of the gravel before back-filling with soil.  (Information on French drains.)  A French drain is depicted by the lower black line in the nearby sketch of an early concept of hour house.  The drains will lie several feet below the conduits for the AGS system (red) so as to keep the soil above them dry year around for proper functioning of AGS.

Our French drains will be slightly different in that we will need a geotextile fabric that is designed for the type of fine silt laid down on our bluffs by the wind after the glaciers receded.   The type of fabric that is available in retail outlets would quickly clog and make the French drains useless. (Comparative study on geotextiles.)  



Back-filling to the Level of the AGS Conduits
The conduits for the Annualized GeoSolar system will comprise ten 4" diameter mostly flexible pipes ( red in the sketch) running between the solar collector (blue) and the solar chimney (green).   (See discussion of AGS conduits.)

After the fabric is lapped over the French drains, we will back-fill with soil until we get to the level necessary to support the AGS conduits.  The backfilling will have to be done in "lifts" (layers) of 8" or less then compacted with a rented vibratory drum roller, either the kind the operator sits on or walks behind and controls wirelessly from a lanyard around his or her neck.  

Compactibility of the Soil
The silt that we have is not as compactible as gravel or soils containing gravel and sand, or even clay. Therefore, it is necessary to amend the soil with something like agriculture lime in order to reach the level of compaction necessary to support the footings and the slab floor (input from retired civil engineer).   If so, we may have to rent a tiller for the track loader to stir the limestone into the soil before compaction.

Completing the Back-fill
After the conduits are laid -- two to a 6' wide trench positioned as far apart as possible -- filling will proceed in compacted lifts until it reaches the level necessary to support the gravel base under the concrete.

Finishing the Floor Excavation
The slab and its gravel base need to rest on undisturbed soil.  Since the loess silt is so easily disturbed, we will deliberately not excavate initially to the final depth for the floor. Then, after the track loader and other heavy equipment has stirred up the top layer of soil during excavation and back-filling for the French drains and conduits, we will carefully remove additional soil until the exposed soil is either undisturbed (between trenches) or thoroughly compacted (over trenches).  We can probably remove most of the loose soil with the track loader if done in a controlled way.  However, we will be removing some the hard way -- by hand. 

Ground-breaking Schedule
Because of the peculiar nature of our soil, the long time it will take us to excavate and our limited budget, the soil engineer recommended not starting excavation until the late summer dry season.  Then, if it rains, it will not likely be torrential and, with tarps, we might be able to keep the critical parts of the excavation from eroding or becoming saturated. 

Wind Blown Loess
Based upon the four core samples, our soil seems to be mostly wind blown loess, a type of fine silt with an interesting history.  It began as out-wash from the glaciers as they receded, then it was picked up from the Mississippi River flood plain and deposited on top of the bluffs by the wind.  Our deepest piezometer hole was 20' deep and the soil core from the bottom of the hole looked very much like the soil beginning just below the topsoil -- no clay, sand, rocks, etc., just silt.  The soil engineer says that it is 50' deep in some nearby locations.  

The particles are extremely small and elliptical-shape such that the wind action aligned them parallel to one another before rainwater locked them tightly together. Today, cuts have been made through these bluffs for interstate highways and the resulting vertical surfaces have remained uneroded as long as the organic cover has not been disturbed.  If the cover is disturbed, like we will be doing, heavy rain not only erodes the soil very quickly, but, where water pools, it becomes totally unmanageable even for seasoned contractors, much less a DIYer.

Design - Excavation

This post was written at an early planning stage whereby I intended to minimize cost by doing most of the work myself.  When it came time actually to do the trenches for the French drains and the AGS conduits, we were in the midst of the rainiest Spring in history. It became necessary to get as much work done as possible between rains so we enlisted professional help for the trenching as well as for grading for the slab floor.   It took several posts to cover the installation of the French drains and AGS conduits. Here are links to those posts:  First post on French drains, Second post on French drains, Last post on French drains,  First post on AGS system, 

Excavating to Floor Level

Since the building site slopes about 15 degrees, the excavation for the house will be 

Building site -- 15 degree south-facing slope

about 6' below grade at the back wall and at grade at the front wall, which means it will involve cutting but no filling.  I estimate that the excavation for the house and garage will take four or five days with the track loader having a 6' long bucket and carrying the soil for storage 50' to the north.  The back wall will be two stories high which will eventually require an additional 6' of backfill on top of the original grade.

Excavating Below Floor Level
The excavation would be rather simple if it weren't for the need to bury the conduits for the Annualized GeoSolar (AGS) system (previous description of conduits for AGS). The conduits will be ten in number and range from 5' below the floor level at the front wall to 3' below floor level at the back wall.  To make things even more complicated, the piezometers that we placed and monitored for three years, told us that a French drain system* would be necessary to keep the AGS system isolated from the rainy-season water table.  It will comprise seven separate drains 15' - 20' apart east to west, about 10' below floor level, canted southward by 1/4" per foot and reaching daylight downhill where they will drain into a rain garden.

Excavation Equipment
Remember the adage, "When your only tool is a hammer, everything looks like a nail"? Well, our track loader is our hammer so I need to devise unorthodox excavation methods to stretch its functionality.   Even then I anticipate having to rent a mini-excavator (small backhoe) for a few days for final shaping of the French drains.

French Drain Trenches
After the basic  house excavation is complete, it will be necessary to trench down another 10' for the French drains.  It is too dangerous to work in a narrow trench even half that depth so, if it needs to be wider, why not use the hammer I have and make it 6' wide (which is probably not a whole lot wider than is necessary for safety?).  I will be moving a lot more dirt than a professional would but I have the loader for putting it back in the hole and all it will cost is a few extra tanks of diesel fuel and a few days time.

At the bottom of the 6' wide track loader "trenches", I plan to dig proper trenches for the French drains approximately a foot wide and a foot or so deep using a rented mini-excavator then finishing with selective hand-digging.

For the rest of the story, go to more details on our excavation.
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*  Information on French drains.

Timeline - Annualized GeoSolar (Cont'd some more)

This is the third in a series of three posts on Annualized GeoSolar, the passive system for heating and air conditioning that we will use for our energy neutral house. To view the previous posts, go to Annualized GeoSolar AND Annualized GeoSolar (Cont'd)

I became acquainted with the system 7 years ago when stumbling upon an online paper by Don Stephens*.

Insulation-Watershed Umbrella
Carmondy/Sterling and Hiat seemed to have been the first to advocate extending the insulation and waterproofing horizontally below grade, as opposed to attaching it directly to the outside of the roof and walls of the house as was prevalent at the time of their writings.  Hiat called the arrangement the "Insulation-Watershed Umbrella", which is the terminology that I have adopted (as opposed to Stephens' "Moisture-diversion membrane/insulation cape").

Copied from p. 41, Hiat's "Passive Annual Heat Storage" (click on the image for a larger view)

Our iteration of the umbrella will comprise (from top down) the following layers:  (a) plus or minus two feet of backfill; (b) two layers of carpet with the top layer shingled upside down (per Stephens) to protect the umbrella from physical damage from burrowing varmints, garden tools, roots, etc. as well as keeping the carpet out of the waste stream; (c) two layers of 6 mil plastic sheeting; (d) foam board insulation; (e) 6 mil plastic sheeting; (f) with a thin bed of sand between each layer.

Why a 20 Foot Umbrella?
According to Hiat, it takes six months for a unit of heat to travel 20 feet through dry soil. During the summer, the solar collector heats the soil under the house as well as under the umbrella.  Then it takes six months of cold weather for any heat next to and under the house to travel the 20 foot distance to the periphery of the umbrella.  By that time, the solar collector is already recharging the system.  The distance can be shortened by slanting the umbrella downward from the house.

Critical Design Consideration for AGS
For the system to work, however, the soil under and around the house must remain dry for two reasons. Water passing through the soil carries heat away to the water table faster than the collector can manufacture it.  Damp soil, much less wet soil, is more thermal conductive than dry soil and, not only robs heat from the thermal mass, but pulls heat out of the house as well.

Four white pipes are piezometers for monitoring the water table

The umbrella protects against surface water but not from the water table. In wet climates such as ours, several test holes equipped with piezometers** should be used to monitor the water table through several seasons, if possible, to be sure the table remains several feet below the level of the AGS conduits.  If it does not, a French drain system*** must be installed well below the conduits, otherwise heat will be lost to the water table.  Our piezometers (four) told us that we needed a French drain system that, unfortunately, would complicate the excavation and drive up costs for the AGS system.

By having an earth bermed back (north) wall two stories high and half of the west wall, our project will take advantage of AGS without earth sheltering on the roof nor against most of the east wall. The reason is that the floor and tall north wall provide enough earth contact for heat transfer and the house will be super-insulated to retain the heat.   Otherwise, our adaptation of AGS will be pretty much like Hiat and Stephens describe it. The exact design of the all-important north wall and the solar collector is grist for a future posts.
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* Although Stephens' paper, www.greenershelter.org/TokyoPaper.pdf, is no longer available, it can be accessed indirectly via Stephens' definitive paper.

**Information on piezometers
***Information on French drains

           *          *          *          *          *          *          *          *          *          *

Update:  Autumn of 2016
By the autumn of 2016, the AGS system was nearly complete, lacking only the umbrella for the north side of the house and the functioning parts inside the solar collector. Consequently, additional discussion on AGS and the details of construction can be accessed through the following links:

Amount of earth sheltering and configuration of the earth contact north wall
Final decision on the amount of earth sheltering

Design of the insulation/watershed umbrella - first post
Design of the insulation/watershed umbrella - second post

Installation of the French drains - first post
Installation of the French drains - second post
Installation of the French drains - third post

Construction of the solar collector - first post
Construction of the solar collector - second post
Construction of the solar collector - third post

Installation of the insulation/watershed umbrella - first post
Installation of the insulation/watershed umbrella - second post

Installation of the insulation/watershed umbrella - fourth post

Wikipedia's description of AGS  is also a good reference.

Final Cost
With sporadic help from volunteers, I did most of the installation of the AGS system except for digging the hole for the solar collector and trenching for the conduits, so our cost was mostly for materials -- foam insulation (biggest item), concrete blocks (second biggest), sheet plastic, fibercement parging, gravel/sand and piping for the conduits. Without the French drains, the cost for installing the AGS system probably would have been less or about the same as for a conventional HVAC system. However, the professional help with the collector and conduits raised the cost to at least to that of a minimalist HVAC system that would suffice for a home that is south-facing, super-insulated, partially earth sheltered and protected by an insulation/watershed umbrella.  It could be argued that the French drains were necessary anyhow for a partially earth sheltered structure in a site with potential water table problems. If they are factored in, the cost clearly exceeded that of a conventional HVAC system.

However, the story is not complete.  It remains to be seen whether our grand experiment performs as expected.  We will be monitoring and reporting here on the thermal performance for several years after occupancy.  If it performs as expected, the pay-back for the extra cost will accrue over time as we avoid the cost of energy and maintenance on heating and air conditioning equipment.  Also we will be insulated from future spikes in rates, be free of furnace and compressor noises and can take winter vacations without worrying about frozen pipes from furnace failure.  And best of all, the environment will benefit once we begin breaking even with the utility company.

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Update:  Summer of 2021

The summer of 2021 was the first opportunity to check out the efficacy of the AGS system.  We found that spontaneous flow of warm air from the collector through the conduits and exiting from the individual conduits behind the house did not occur.  It was necessary to bring the conduits together into a solar chimney and add a fan to pull the air through them.  Here is a  link to the post that describes in detail the modifications that we made and a thorough critic of our design including suggestions for a similar system without a solar collector. 

Timeline - Annualized GeoSolar (Cont'd)

This is the second in a series of posts on Annualized GeoSolar, the passive system for heating and air conditioning that we will use for our energy neutral house.  To check out the first post, go to Annualized GeoSolar.

I became acquainted with AGS 7 years ago when stumbling upon an online paper by Don Stephens*.

The Father of AGS
Before discussing AGS, I would be remiss if I failed to give credit to John Hiat who, in my opinion, is the father of AGS-like concepts.  He self-published his spiral bound "Passive Annual Heat Storage -- Improving the Design of Earth Shelters" in '83. Stephens subsequently improved Hiat's PAHS and called it AGS but his detailing of the whole system is much sketchier than Hiat's. In fact, I think anyone contemplating building or buying an earth shelter would be remiss in not reading two books -- Hiat's book and that of Carmondy and Sterling, "Earth Sheltered Housing Design", (Hiat gives much credit to the latter in his book). (Both books are out of print but, as of this writing, were available on EBay.)

Hiat's Influence
Until Hiat and Carmondy/Sterling came along, I am pretty sure passive solar heating was universally synonymous with solar energy from the winter sun (irrespective of earth sheltering). Stephens refined their work and named it AGS to differentiate its year-long cycle from the spasmodic daily, or even hourly, cycle of conventional passive solar heating that depends on the whims of winter sunshine.  

Hiat's iteration of the insulation/watershed umbrella

How do PAHS and AGS Work?
Both writers advocated using concrete for at least the floor of the house, installing lots of south-facing glass and earth sheltering the roof as well as most of the west, north and east walls. Both advocated keeping the soil around and under the house dry and insulated by extending waterproofing and insulation horizontally from the house below 

grade and outward twenty feet in all directions, thereby maximizing the thermal mass available to absorb, hold and dispense heat.  I have chosen to adopt Hiat's terminology for the horizontal insulation and waterproofing --  "Insulation-watershed umbrella".

Solar collector (blue), conduit (red), solar chimney (green)

Stephens' important upgrade was to use a homemade solar collector downhill from the house with conduits, tilted slightly upward, running under the house and exiting to daylight behind the house in a solar chimney.  The collector is designed to maximize solar gain from the summer sun and the conduits are designed to carry heat passively to the soil under the house before exiting via the chimney.

Managing the System
When cool weather approaches, the chimney is closed so that cold air does not drop into the conduits.  The heated thermal mass (concrete floor and walls plus the soil beneath the floor, under the umbrella and behind the earth contact walls) then maintains an even temperature within the house during the winter, independent of passive solar gain through the windows. Spring arrives, the chimney is opened and the collector begins to recharge the system before enough heat has escaped around the edges of the horizontal insulation to lower the temperature in the house more than a few degrees, if any.

Year-round Comfort
The year-round temperature can be slowly (over a couple of years) adjusted to, and then maintained at, any desired temperature, say 74 degrees, plus or minus two degrees. In addition to providing heat during cold weather, the massive heat sink plays the role of air conditioning by absorbing any summer heat penetrating the envelope of the house and storing it for the next winter.

CLICK HERE to access the last post on AGS
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* Although Stephens' paper, www.greenershelter.org/TokyoPaper.pdf, is no longer available, it can be accessed indirectly at Stephens' definitive paper

Timeline - Annualized GeoSolar

Six Years Ago

This is the first of three posts on the subject of Annualized GeoSolar  that, according to Wikipedia, makes our green building project almost unique for the US .

Vacation with a Hidden Agenda

Early in my research on earth sheltering, I came upon a posting by Don Stephens* describing what he called "Annualized GeoSolar (AGS), which was incredibly intuitive and a game-changer for us.  So much so in fact that, about six years ago, we deliberately vacationed in the northern high desert in hopes of wrangling a visit to a house he had designed.

Fortunately, Don arranged a visit to an earth sheltered home just south of Spokane that he had designed for a retired veterinarian and his wife who built it themselves.  The unique feature, in addition to being a straw bale house and fully earth sheltered, was that it harvested the heat from the summer sun for its year-round comfort without conventional heating or air conditioning or depending upon passive solar from the winter sun.

Concrete structure with earth roof; no A/C but notice the chimney

Broad Picture of Earth Sheltering
My current understanding of earth sheltering is that, by the time of our visit out West, most of earth sheltering was still 1970ish concrete walls with either concrete or wood for earth contact roofs, sophisticated waterproofing and insulation fastened to the outside, passive solar during the winter supplemented by non-fossil-fuel heating such as wood, corn or pellet burners -- usually stoves, furnaces or masonry heaters. Actually, there were even many "earth homes" left over from earlier times that had little or no waterproofing and sometimes less-than-sophisticated insulation if they had any at all. Even the 1970ish homes had several drawbacks in varying degrees that gave us pause: (a) being at the mercy of 50 to 60 degree ground temperatures in winter, (b) in humid areas such as ours, condensation problems in summer, and (c) water problems during the wet season. However, with or without insulation and waterproofing, they still had a leg up on conventional homes with respect to energy conservation.  In summer they needed little or no air conditioning and in winter they were easy to heat so long as the occupants did not mind cold floors.

The Mueller Earth Sheltered Home Was Different

Here in the high desert we were standing in a house in a cold 6,000 heating degree zone with less mean percent of possible sunshine than we have in our less-than 5,000 heating degree zone in Metro St Louis.  It was a house that had not yet required help from its back-up electric baseboard heaters in the three years that Marilylenne and Joris Mueller had lived in it and a house with pleasantly warm floors during their long winters.

The Mueller's construction methods, which faithfully followed Stephen' recommendations (a summary paper by Stephens), gave new meaning to "minimalism" and "sustainability", which is to their credit but also contributed to their misfortune. Their iteration of AGS included a tad more minimalism than was good for long-term thermal performance of the AGS system.  They used straw bales for the insulation in their insulation-watershed umbrella (which we will soon define), some of which got so wet and non-insulating as to necessitate a wood burning stove.  In our view, their misfortune is not a knock on AGS but is a warning not to get too simplistic with it.   (The Muellers' "Mica Peak Residence" is the first example in Stephens' paper.)  

CLICK HERE for the second post on AGS.

CLICK HERE for the third post on AGS.

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* Stephens' original paper -- www.greenershelter.org/TokyoPaper.pdf -- is no longer available on the web.  However, it can be accessed in a round-about way via Stephens' original detailed paper .

Realistic Assessment of Our Environmental Impact

The book, "Eco Architecture", is one of the Opposing Viewpoints Series published by Gale Cengage Learning and has 21 contributors.  It explores the pros and cons of the green building movement and sustainability/environmentalism in general. A recent re-read of the book reminds me that we need to keep our project in perspective, especially now that we are out front blogging about it.  

Why are we doing it?
The reasons fall into two categories.  The first is simply economic -- to save money on the construction of a customized home and on future energy costs.  This reason would hold more water if we were younger, but at our ages, only the savings on construction is a factor; future savings on energy not so much.  So there must be other more transcendent reasons.  

Salvaged lumber will help to minimize carbon footprint

A view from below the stacks

Build vs. Remodeling

However, thinking that we are having a significant direct positive impact on the environment is not one of them.  As far as a carbon footprint during construction is            concerned, we could do more for the                        environment if we were to buy an existing house and remodel it.  Pouring 
a concrete floor for our house will probably release more carbon than whatever we would do to remodel an older home whose carbon has already been sequestered.  This carbon imbalance would especially be true if we were using conventional building methods.  However, because we are intentionally using non-standard methods and materials, our effort may have a small positive impact on the environment over remodeling.  The real benefit to the environment, though, will be through little or no energy consumption over the life of the house to an extent not possible with a remodel or with standard new construction.  But even then, we have no illusions about our minuscule contribution to sustainability.

Demonstration Site
As a dental educator, I always felt that I had a greater impact on dental disease than would be possible by merely practicing dentistry.  In the same vein, when we blog about our home and open it to anyone who is curious, there is a potential for a greater impact on the environment than we could have alone. To quote Jo Scheer in "Eco Architecture", "Though extreme eco-architecture may not be a solution to a thoroughly sustainable building industry, it certainly provides ideas.  It is a model of ideas and concepts that beg to be assimilated".  

Cutting-edge High
The 40 years I was in dentistry was a unique time.  I was fortunate to have gotten in early and ridden the cutting edge of a new discipline until it matured into a sub-specialty.  We were often pushing the envelope to an extreme and sometimes uncomfortable degree and made a few bad choices.  But we also got an undeniable, reinforcing high from our preponderant successes.  I will have to admit that this past experience has made me eager and confident to be an early adopter in another arena. I know that not all of our non-traditional and untested methods and materials will be entirely successful.  But I also know that our diligent planning and preparation, combined with a ridiculous amount of perfectionism during construction, will lead to a successful outcome overall that might influence mainstream eventually.  (Recent update:  As if the end of 2016, the number of visitors to our blog surpasses my fondest dreams.  So just maybe, its impact could be considerable after all.)

Bucket List
Long before I began to think environmentally, I had the totally impractical itch to take a year or two off and DIY a home.  Well, late in life when I finally got the opportunity, Dottie made the mistake of saying "yes".  All of the foregoing reasons for doing our project are worthy, but without sticking so tenaciously to the bucket list, I doubt it would have happened.

Odds 'N Ends - Dottie's Garden

Critter Problem
Our property lies in the heart of the Mississippi River bluffs.   Not many streets in our town are continuous for more than a few blocks due to a network of ravines and "hollers" that are characteristic of river bluffs.  (In fact, rumor has it that Collinsville holds the worlds record for "No Outlet" and "Dead End" road signs.)  The ravines are forested with typical edge cover between peoples yards and the trees -- perfect wild animal habitat.  And living with wildlife is great except when it comes to gardening. Ground hogs, rabbits and deer are the four-legged critters that can be most destructive but can be deterred by a proper fence.  Insects, birds, squirrels and raccoons are another matter, although the latter two so far have not been a problem.

Critter-proof fence
We installed a typical 5' livestock woven wire fence around the 30' x 50' garden. Under the bottom of the wire, we buried pressure treated 2 x 6s on edge to discourage moles, gophers, ground hogs and digging rabbits.  Next we attached rabbit fencing along the bottom of the woven wire fence and stapled it to the tops of the 2 x 6s as further rabbit proofing.

Obstructions and torturous pathways to discourage jumping deer.

Outwitting the Deer
But what to do about the deer who have no trouble clearing a 5' fence from a standing start?  As a result of surfing the internet, Dottie laid out the pathways and plantings in mini-maze fashion so as not to give jumping deer clear-cut landing areas.  But just to make sure there were no safe landing areas, she hauled in all matter of junk metal, such as bed frames, rebar and big things that defy 
description, and positioned it in such

a way that no self-respecting deer would risk a broken bone or a concussion by jumping in.  Then she strung brightly colored streamers from the tallest piece of junk outward to the corner fence posts.  Finally, she strung heavy translucent fishing line from post to post 6" or so above the top of the woven wire. Apparently, curious deer are repelled by contacting the line with their noses at night. Judging by the fact that the line has been broken a couple of times with no signs of deer in the garden, either the junk or the line or both are working.  Or maybe they are repelled by the dill plants around the periphery and the Marigold plots within -- both reputed to be offensive to deer and other invaders.

Junk appears soon after the initial tilling 

Insect Patrol

Dottie grew up in a big rural family that depended heavily on its garden. Being the eldest child and, as such, a surrogate mother to her younger sibs, she was only too happy to spend time gardening in order to get some personal time. Hence, her green thumb today.  Those of us who have never gardened fail to appreciate its nuances beyond tilling, planting, weeding and harvesting.  Insect patrol is one of these.  I swear she can spot an aphid from 20' away.  She opens into the squash stems to excise a borer that kills the plant otherwise.  Her major effort last year was against the Egyptian beetle (stinkbug) that bloomed in these parts.  The methods she used are too complicated and off-the-wall to address here except to say they did not involve store-bought insecticides.

No-till
The garden was tilled initially to kill the turf.  Since then, it has been no-till which not only cuts down on the amount of work but is more sustainable.  She starts saving cardboard boxes in the early Spring.  When planting season arrives, she flattens the boxes and covers the ground with them.  To plant seeds in a row, she cuts a narrow strip out of the cardboard or leaves space between boxes and plants through the hole.  With plants, like tomato plants, she makes an "X" shaped cut, folds the flaps back, plants the plant and closes the "X" around it.  Then she covers the cardboard with wheat straw.  The cardboard keeps the weeds from sprouting and keeps moisture from evaporating from the ground.  The straw also helps hold in moisture but, to my way of thinking, it covers up the ugliness of the cardboard until the plants get tall enough to hide it.  (So far, the neighbors have been very understanding about the junk, the streamers and the cardboard, although it probably helps to have shared the veggies with them.)

Irrigation
Dottie's farmer-brother-in-law accumulates an obscene number of PVC 2 gallon containers after mixing the surfectant with his Roundup for crop spraying. He suggested we drill a holes at their bases, fill them with water and set them next to plants needing irrigation.  Accordingly, by trial and error, we found that a 1/16" hole will require 2 hours for 2 gal of water to irrigate the base of a plant.  Also at his suggestion, we covered the bottom of each container with an inch or so of pea gravel to stabilize against the wind and, in case the can does not set level and some water is retained, to keep from breeding mosquitoes. The containers kept us from loosing bare-rooted seedlings during the 2012 drought and since have come into play in the garden, for new seedlings and for the new blueberry patch.

Native Plants and Therapy
Amongst the veggies, Dottie is growing several varieties of wildflowers that will eventually to be part of the native landscaping after the house is built.   Meanwhile, they add interest to the garden and are safe from construction activities.

The garden is Dottie's sanctuary -- her relief from her multitasking world.  And it is a great way for her to squeeze in some strenuous exercise that's good for her sciatica.

September 2015 Update
We are happy to report that the deer still have not invaded the garden but the groundhogs have.  Dig under the fence, you say?  Nope, they climb the fence high enough to get over the secondary rabbit fencing then jump off.  As bulky-looking as they are, who would have thought that they could squeeze through a woven wire fence?  Japanese stink bugs wreaked havoc last summer but have not been a serious problem this year.

Timeline - Education on Earth Sheltering (Cont'd)

About 7 Years Ago

This is the second of two posts on the subject of Education on Earth Sheltering. The first post can be found at first ES post..

A Game-Changer

Even before latching onto the Carmondy and Sterling's book, "Earth Sheltered Housing Design", I ran onto a web posting that made overwhelming sense despite my limited understanding of earth sheltering at the time.  I put it on the back burner but kept going back to it.  The posting was by Don Stephens, an architect from Spokane. The long title was ""Annualized Geo-Solar Heating as a Sustainable Residential-Scale Solution for Temperate Climates with Less Than Ideal Daily Heating-Season Solar Availability". Unfortunately, all of Stephen's postings -- such as www.greenershelter.org/TokyoPaper.pdf. --  appear now to be  inaccessible.  However, the following link is a round-about path to the Original Paper.

Annualized GeoSolar

I will have at least three posts upcoming regarding the details on  AGS.  (Recent update: You can now click on the "Featured Post" in the column to the left to access the three posts).  At this juncture, just a brief description should suffice.  Instead of typical passive solar heating that depends upon the whims of winter sunshine, AGS uses a homemade solar collector to harvest heat from the summer sun and pipe it under and around the house for storage in the earth for wintertime heating and summertime cooling.  And, unlike the Rob Roy type house, the waterproofing and insulation are not in intimate contact with the house but are laid horizontally a couple of feet below grade, thereby keeping dry and warm a thermal mass that is much larger than the footprint of the house.

Passive Annual Heat Storage

As it turned out, Stephens was merely improving on the groundwork laid by another out-of-the-box thinker, John Hiat, who had established the "Rocky Mountain Research Center" and self-published a spiral-bound book, "Passive Annual Heat Storage -- Improving the Design of Earth Shelters".  As he says on the cover, his concept "takes solar energy out of the dark ages".  Unfortunately, the book is out of print; I checked it out through our inter-library loan then bought one on EBay.  I would give anything to talk to John Hiatt before we start our project and but my attempts to connect with him have failed.

Just like AGS, PAHS is earth sheltering protected by the horizontal waterproofing and insulation but does not use a solar collector.  The thermal mass under and around the house is more gradually heated to a year-round stable and comfortable temperature by summer and winter solar gain through windows as well as heat generated by merely living in the house such as water heating, cooking, clothes drying, light fixtures, even human body heat.  

Our Commitment to AGS
Stephens writings about AGS are not loaded with how-tos whereas Hiatt's book is all about them, without which I would probably be reluctant to go with AGS for us.  (His book, in my opinion, is a must read for anyone contemplating building or buying an earth shelter and Carmondy and Sterling's book is a close second.) In a sense, Stephens planted the seed for us and Hiat and Carmondy and Sterling did the fertilizing and watering to the extent that I feel like we can follow, with minimal deviation, the prescription for AGS-PAHS and get it right the first time.

Later, when discussing AGS in detail, I will tell about an interesting visit to a home near Spokane that Stephens designed.  Google searches have not turned up any other homes that followed Stephens' design precisely -- most of the chatter is about modifying and adapting it instead of buying the complete package. There is one mention of a couple of homes that seemed to have faithfully followed Hiat's design: PAHS in Missoula.  (Recent update: The latest description of AGS in Wikipedia references two current projects in North America -- Drake Landing in Canada and our project in Collinsville, although its link to our blog doesn't work.)  Unlike that of Stephens and Hiat, earth sheltering for our iteration will be limited to the story-and-a-half back (north) wall and half of the west wall instead of the roof and east wall being sheltered as well.