The Culvert House
[Presented at the Alternate Energy Association Meeting
Nov 17th at the Public Library of Cincinnati & Hamilton County
Resource links and references listed below]
SPECIFICATION TIME OR WISH LIST__________
Imagine a house, here in the Cincinnati area, ....
*whose shell was impervious to even severe weather hazards,
*whose monthly energy cost for heating and cooling was negligible,
*whose energy & water systems were designed for ease of maintenance & usage,
*whose floorplan was ergonomically designed to support your extended family´s desires for both private space and communal resource sharing including areas for their homebased businesses,
*whose landscaping was natural and suitable for experimenting in minimal agriculture,
*whose interior environmental systems offered pure air and drinking water with hazards designed out and simple hedonistic pleasures designed in,
**but whose building cost was minimal relative to standard construction....
How much convention would you be willing to dispense with to meet these specs?
For the last four years I´ve been researching possibilities, combing the libraries, talking to other experimenters and experts, as well as studying and quantifying our family´s priorities and resource usage. Some paths dead-ended but enough are unfolding that I think this time we may have it, even on a difficult site. At present, for transportation, location and economic reasons, we´re looking at an acre on a steep, north facing slope, with no water and no sewer... (but very inexpensive relative to its location)
Since this puzzle has a lot of pieces, let´s define them separately and then try to visualize the assembly afterwards.
The alternatives for extreme weather designs include the geodesic dome and the underground house. We abandoned the dome when it´s incompatibility with the monthly energy solution became apparent and began the search for an underground house to meet the construction costs requirement.
Among the underground house designs that was tried during the energy crisis of the 70s was one by Michael McGuire, Minnesota architect, which was dubbed the culvert house. The shell of the house was described as being a steel culvert, normally used for drainage systems and road work which gave the house an extremely economical and structurally strong basis. It appeared in many publications and the beauty of its geometry and the natural way it blended with the land was visually striking.
When I followed up with McGuire by phone a couple years ago, he no longer had easy access to those files, having long ago stored them and moved physically and in his work-focus to other areas. But he said the structure had actually been an agricultural building and he had only a vague recollection of the manufacturer´s name and location. Amazingly the cost of the metal building had been $700 in 72. He said the specs had been worked out by the engineer on the project but when I called the engineer he said he´d done very little.
The house itself is in Wisconsin and, according to McGuire, the owners were quite satisfied and there´d been no problems though he´d heard of someone who´d attempted something apparently similar on their own with less success. I began the search for the manufacturer and believe I´ve located the successor as well as a trail of resistance.
The *less success* must have been frightening enough that some manufacturers of steel buildings and even suppliers of steel culverts will shut you right down if you even suggest the phrase "underground house". Even the ones who admitted that they´d built exactly that for the feds... which I learned about from a salesman who had more experience and was willing to talk. Another salesman told a story of a fellow who´d used their building successfully underground but hadn´t told the supplier in advance what he was planning.
Though I never found anyone who actually knew the details on the *disaster*, I suspect it was related to a comment I read in a book on steel culverts used in road work. The book explained that these structures needed to be properly buried... layer by layer, evenly from side to side, not in some lopsided fashion. Their strength depends on the balanced pressure and the weight bearing properties of the earth they are surrounded by.
The original company seems to have been a small multi national outfit serving both the US and Canada. It underwent some form of corporate upheaval and its current incarnation is willing to supply the building but they can´t do the engineering I will need to determine the gage and specs. So my next objective became to research culvert engineering and find an engineer here to handle the ultimate calculations. I´ve been working with AEA´s John Hubbard, who looked over my calculations and approved the extrapolations I´d done on drainage culverts. It looked, based on estimates of deflection, ring compression, buckling stress, crush threshold and seam strength.... that the determining measure was the seam strength. *Assuming* the closest road culvert corrugation dimensions were *close enough*, the gage would need to be 18 not the usual gages of 20 and 22. The dimensions were not really close but we were satisfied that the calculations were doable if we just had reassurance that the parameters for the building´s corrugations resembled standard culverts. But the input data for these *more similar* corrugations was nowhere to be found in print.
The manufacturer wouldn´t consider providing that kind of support unless we´d ordered the house and it wasn´t entirely clear whether the data we needed was what they would have later provided... maybe it was, but the salesman was not certain, and I didn´t have access to their engineers directly.
Meanwhile, I was looking at the current cost of an 18 gage version. If that was the gage McGuire had used in 72, then the price of steel had risen 11% per year for every year for the last 25 years without exception. There was even the possibility that the location I would be putting this structure on would be very steep altering the calculations for the deeper culvert, increasing that component´s cost another 25%. The thought of the excavation problems and the difficulty of finding a crew with experience resurrected John and Andy´s concern about the logistics of burying this shell.
So even though the simple metal shell might be ideal for the monthly energy solution piece of the puzzle, I couldn´t get over the ease of burying the shotcrete-sheathed metal-webbed designs that I´d explored while looking for the mysterious metal building. At that point John Hubbard and I began discussing reducing the gage of the shell till it was merely adequate to support the application of shotcrete or gunite. We´re currently investigating concrete additives that would make the gunite both lighter and stronger. John recommended flyash, reclaimed from generation facilities, based on work of a colleague of his. So now I´m trying to get up to speed on workability, cost, strength, reinforcement possibilities and the chemical properties of concrete, as well as studying application equipment and looking for possible crews.
THE INSULATION UMBRELLA________
Randy was the one who introduced me to the concept of passive annual heat storage or PAHS. The concept came out of the Rocky Mountain Research Center in Missoula MO in the mid 80s. By that time it was too late to benefit from the energy crisis momentum of the 70s and emerged, unfortunately, after underground houses had acquired the reputation for leaking and a lot of related expensive solutions.
Following Randy´s recommendation I began accumulating publications of PAHS creator, John Hait. Quite a creative character, John Hait is currently consumed with computer innovations. His clients during the days when he was personally promoting PAHS were primarily survivalists, one of the few groups to sustain an interest in underground houses after the energy crisis curiously faded.
Via the internet I got a chance to discuss some questions I had with John and he gave me the address of the only one of his clients willing to share their experience. Survivalists tend not to be chatty. Speaking to Lin Bleeker of South Dakota was very helpful, particularly the fact that there had been no water problems, no plant or animal complications with the umbrella or the earth tubes and his heating expenses for the last eleven years were under $100 total... an average of less than $9/year over 11 years of Dakota winters. Since his home is one of Pearcy´s underground concrete-over-metal-web designs of fairly substantial size, his satisfaction was particularly reassuring.
So, you´re asking, what is an insulation umbrella? What´s PAHS? Hait reasoned from some of the thermal performance data of research and experience in the 70s that he could, and did, create a dry, thermal storage area around an underground house by layering plastic sheeting and styrofoam insulation board in a sandwich about 4-6 inches thick, at a depth of about 2 feet beneath the ground surface and extending about 20 feet beyond the perimeter of the house. At that depth it´s clear of roots, frost, light and is non-biodegradable. The earth beneath the umbrella stabilizes at a new temperature creating a sort of heat-sink in which the house is embedded. In the summertime the heat entering the house dissipates into the sink, reaching the 20 foot perimeter by the time the season changes to cold weather and then providing warmth for the house to draw on as the winter above draws heat from the house and secondarily from the storage... creating a year-long flywheel effect. The layers of plastic, the appropriate slopes and escapes at the edges divert surface water from entering the heat storage area, including sheltering the house from everything but errant watertables. So we´ve been consulting the catalogs of soil types from the soil conservation people. Anyone ever used a dowser?
And the earth tubes? The earth tubes are PCV-pipe systems that circulate tempered air between the house and the outdoors, beneath the umbrella, facilitating heat transfer and airflow.
To our advantage, this system is better installed by the owner for quality and savings. The materials are inexpensive but they require attention to properly layer them like a system of shingles, taking some care while covering them. Among local underground home builders, AEA´s Chaz Kaiser closed his own underground dome in with his bobcat. Some author/builders of underground homes recommend investing in a backhoe and taking your time to do the work. The ´hoe was said to be operable by a novice and to retain its value so you could recoup your investment when the work was through. I have a line on one but it´s in Virginia... so I´m looking at transport options...
THE FLOORPLAN, ENERGY, WATER AND ENVIRONMENTAL SYSTEMS_______
Ergonomics, maintainability, economics and health are the main criteria for decisions on the interior systems and design. To date the main decisions have been more a matter of creativity than conflict so we haven´t had to test alternatives against our defined priorities.
The key to keeping the size, required for an extended family group house with enough space for home based business too, from conflicting with the economics of the shell was to design the floorplan within the confines of 25 ft diameter shells. (Cost escalates much more rapidly than diameter.) To do that we laid three culverts side by side, with their open ends east and west, and mimicked a floorplan we had good experience with. With sunrooms at each end of the longer culverts and berming the ends of the middle culvert for the business/utility areas, the solar requirements to run the flywheel should be met.
According to Hait, the east-west window arrangement, with glass about 15-25% of the floor area, or half of the usual amount of solar design glass, should be ideal because we want the influx of heat into the building to be spread throughout the day so the earth has sufficient time to absorb the input and we won´t experience the swings of traditional solar designs. In addition we will be soaking up the heat in the summer when it´s plentiful and drawing it from ample storage when solar heat is in short supply. The target is to maintain the summer indoor temperature a couple degrees higher than your planned annual average earth-system temperature. The adventure of fully climatizing the earth-system is said to take about three years and you want to plan your open-earth phases at construction time so the ground is closed up before the end of September. Hait recommends shutters and louver systems for controlling the finetuning process and we plan to include them.
Another key to the economics in spite of size is the fact that the assembly of the shells is claimed to be doable by a team of novices with wrenches. Checking with some, including AEA´s own Greg Meyers, who have assembled these kits or similar ones for above ground projects, has provided valuable logistics suggestions for delivery and scaffoldwork to keep handling doable. Even the passageways between culverts are standard components so expensive custom engineering is avoided. The endwalls are my next concern. Combining solar gain, overhangs and the insulation umbrella´s edges without leaving any ´energy holes´ in our armor is the challenge.
The simplicity of Japanese decor, the appeal of the inherent geometry and the beauty of utilitarian logic keep the expenses of finishing the interiors to a minimum. The goals of ergonomics in enhancing the pleasures of everyday activities such as bathing a baby and routine washing led us to replace the enclosed tiny basins that pass for bathroom sinks with more generous but not uncommon kitchen basins. It remains, though, to find the right table to support this objective. Maintainability, safety, comfort and economics were factors in moving all electric outlets to switch height or in a central overhead track for lights and fans. Simlarly, the plumbing will be planned for access as well as keeping the routes compact.
Utilization of the space along the curved walls was a consistent challenge that had me worried but so far seems doable. The site we´re looking at should work with a standard septic system. I´m open to doing some grey water concepts such as for flushing use but not at the risk of the excessively delaying the program and I haven´t found any adaptable standard system or components for just flushing. My current fascination is the possibility of using the swimnspa water as the source for flushing. Solar hot water is practically a certainty... economical and more than adequate for our needs if I can figure out where to put it. PVs though are likely reserved for critical systems only like the well pump, because they´re still too expensive for me compared to our rural electric co-op option at the site.
The environmental systems under consideration include zoning, dehumidification, aircleaning, and heat exchanger. We´re still trying to estimate the amount of water we´ll need to remove from the air. Marty Davis of Davis Caves claims his underground houses were dried enough by using a humidistat to govern when not to run his air-to-air heat exchanger and I´ve gotten different estimates from suppliers of other equipment. Dehumidifier data with numbers like 100 pints per day capacity... or heatpump hot water assists with numbers more like 10 pints per day...
NATURAL LANDSCAPING, MINIMAL AGRICULTURE & WATER QUALITY___
The sunpit (in-ground solar greenhouse) with wellpump, cistern, swimnspa with ozonator, hydroponic-broccoli/lettuce trees,
For the sunroom, a built-in solar cooker/oven, solardryer & sprouts, solarstill/ceramic/UV water purification...
Alternate Agriculture: chicken tractor, onestraw barley, composting, bush orchard for cherries & kiwis, no-mowing creeping red fescue, snowfence/hedge, pavestone or rammed earth retaining walls with cucumber vines, hillside terracing
Refinements: cold storage drapes for airlocking the garage and the sunpit
Energy independence, secure compatibility with the ragged edges
of natural beauty... ergonomic ease to promote the joy of living...
space age balanced with appropriate technology... and all inventively
Those are our goals and progress to-date. If you know of resources
I should consider, drop me a note
and if the puzzle pieces fit,
this presentation will grow and bloom with your contribution and
attribution recorded so we can give a better idea a chance to spread.
And the first to bring us news... and, what news it is, are the Fahrnows... come see their wonderful dream house in Montana´s BigSky Country.
The Latest News in the Hobbit Clubhouse
More experimenters to connect with, and exciting work in progress.. let´s review the log of recent responders.
A feature of
Letters, via snail-mail, should be sent to
J. H. Raichyk
PO Box 54050
Cincinnati OH 45254
Resources & References__________
Alternate Energy Association
John Robbins, CEM, Robbins Alternate Energy
Randy Sizemore of Entropy Limited, 8927 Blossom Dr, Dillonvale, OH 513-891-7620
John Hait, PAHS, Rocky Mountain Research Center, Missoula MT, 406-728-5951
Gene Piercy, Performance Building Systems, 800-247-0090
Dale Piercy, NestEgg Systems
Pat Yentzer, Miracle Steel Structures, Minneapolis MN, 800-521-0386
The One Straw Revolution: An Introduction to Natural Farming by Masanobu Fukuoka
Gaviotas: A Village to Reinvent the World by Alan Weisman
The Hydroponic Hot House by James DeKorne
earth sheltered housing design by the underground space center, university of minnesota