F.A.Q.: Ask Away!
Used-tire built Homes, Consulting & Plans
Frequently Asked Questions
Q. Do you design “Earthships”?
A. Earthship® is a Registered Trademark, owned and enforced by Michael Reynolds who did popularize the name and the usage of rammed-earth-tires as thermal mass walls in a passive solar application. I have no affiliation with Michael Reynolds, Solar Survival Architecture, Inc., nor any of his/it's affiliates.
I design homes using common, public-domain, well known techniques and procedures; many times including forms that mimic “Earthships”, but no more than "Earthships" mimic earlier designs less the rammed-earth tires. I built my own home exactly in the “Earthship” format put forth by Michael Reynolds in 1989 ("Earthship", Vol. I). See: http://www.earthship.org/
I LOVE used tires as a building material; free, apparently ongoing supply (for this moment in time), practically indestructible, plentiful AND as they exist in tire dumps; a nuisance (giving the enTIRE process a definite transformational quality, to say nothing of the ecological value).
I also feel strongly that passive-solar homes, whatever mode of construction is used, are MUCH more desirable and functional than ‘normal’ houses, which today spare considerable intelligence in their design by completely ignoring the sun’s free blessing of warmth and lean heavily on such things as 'curb appeal' and electrical power provided by fossil-fueled energy sources.
Q. What services do you offer? Are you a contractor? Can I buy my solar hardware from you?
A. I draw plans, do site surveys and consultation, both email and telephone. I am not a contractor and do not serve as both the designer and builder, nor do I sell systems or hardware. I will consult on usage of solar systems, but don’t sell them. I feel the two positions are at conflict with each other and the client could suffer as a result of this conflict.
Q. What is the cost per-square-foot for tire houses? Is there a general range?
A. This is almost impossible to predict as a finished product, due to personal preferences, but not impossible to estimate if you know what you want. For the basic starting price of a closed-in shell; figure a minimum of $40/ft², somewhat less if you're able to find free logs for roof members. From there, to finish it can be up to $300/ft² for a turn-key home built by a General Contractor for that ‘particular’ client. Or, can be done quite nicely for $70/ft² by a resourceful, willing to do some work themselves, owner/builder.
Do you install that $2,500 bathtub, or make one yourself? Do you use that $450 gold plated kitchen faucet w/built-in dish-washing wand, or the stainless steel item for $59 on sale at Home Depot? Wildly different per-foot costs result when you get into choices for fixtures, appliances, flooring, finishes, etc. Especially, when sub-contracted hi-cost items are compared to self-installed economical/free/used/scrap items.
Q. Do I need to use a concrete foundation under the tire walls?
A. A concrete foundation is not necessary because tire walls are so thick (2-1/2' for rammed-earth tire walls and 5' for tire bale walls). Both the rammed-earth tire wall and the tire bale wall have just at twice (almost 4X for the bale wall) the bearing surface of a standard concrete "footer". The key to the difference is in the "footprint" of the wall. A framed wall needs more footprint to hold up the roof, a tire wall doesn't.
Q. How long would construction take?
A. Construction could be accomplished in a similar time to ‘normal’ construction. The main difference in construction times is reflected in the amount of money available to the builders. If you are going to build for cash the speed of construction will be directly connected to how much cash (energy) is available, factored by your willingness to pay others to do the work.
Tire bale walls are considerably easier to build than rammed-earth tire walls, as all that is required is to stack them in place. Plastering either type of wall will take approximately the same amount of time/energy to accomplish.
Q. Do I have to have an Architect or Engineer sign or stamp my plans? How much does that cost?
A. If a building permit is required where you intend to build, chances are that you will need to provide plans that have been approved for your application, your lot, and their requirements. In this scenario the strength of the designed structure is usually certified by a Registered Professional Engineer or Architect in the State where the building is to be constructed. I am neither a Registered Professional Engineer, nor an Architect in the State of Colorado. I just draw the plans, and in most cases they must then be stamped and approved as stated above. If you live in Colorado you can count on $150 (& up) as a separate fee, for the engineering approval. If you live out of Colorado and need a permit, you will need to secure the services of an RPE in your State.
Q. What about fire danger? Aren't tires so flammable that they can't be put out once they catch fire?
A. It's true that a pile of tires, once on fire, is almost impossible to extinguish. However, both in the case of rammed-earth tire walls and tire bale walls, there is insufficient oxygen (0% for rammed-earth tire walls and 5% for tire bale walls) contained within them to maintain an ongoing fire and can easily be extinguished. Also, when completed, they are both covered with a minimum of 2" of plaster which will not burn AT ALL. Consequently, both approaches will easily pass any fire requirements (ask your local fireman).
Q. What about used tires out-gassing into the house? Don’t tires do that?
A. Any gas produced by used tires in this application will have to go through at a minimum; a moisture barrier of 6 mil construction plastic film and at least 1" of stucco (cement) or adobe plaster, with nothing forcing it to do so (static pressure, both sides of barrier). NOTE: The surface of used tires has been subjected to years of exposure to oxygen by high speed rotation in the atmosphere. This exposure causes a phenomenon called oxidation. Oxidation 'interlocks' the surface molecules with oxygen and 'out-gassing' (fly-away molecules of synthetic rubber) is considerably limited, if not stopped completely. It's the new tires that stink/outgas, they just need to “rust” for a while, before they are suitable for use as a building material.
Q. Where do I get the tires? What do they cost and how much do they cost to fill with dirt?
A. Any tire dealer will have used tires that need to be ‘disposed of’. Most will be happy that you want to take them away without a charge. Some will even deliver them to your site. Shop around, talk to tire dealers and tire recyclers. As for filling the tires with dirt, many of my clients have paid a per-tire rate to students or day-laborers of between $6 & $10.
Q. Where do I get tire bales? How are they made? What do they cost?
A. Tire bales are where you find them. Although you can count on the fact that a baling machine has constructed them (see: http://www.touchtheEarthRanch.com/balemaking1.htm), the machines are mounted on a gooseneck-hitch trailer and can be hauled by a strong pickup truck (see: http://www.tirebaler.com/ ). This means they can literally be found anywhere.
The bales range in price from FREE to $30 each, depending on where you live, how many bales are available, regulations pertaining to tire recycling, etc. For an up-to-date reading on your local tire-baling machine/bale manufacturer, please email Encore Systems, Inc.'s Ed Drews at email@example.com and ask him where your nearest bales might be located.
Shipping the bales is a definite cost consideration. A semi-truck w/flatbed can haul 24-25 bales per load. To figure transportation costs, call your local trucking agent to find the per-loaded-mile charge from the tire bale manufacturing site to your building site. At this time you should also verify that your proposed route can accommodate a large semi-trailer rig. A tractor/skid-steer w/forks that can 'comfortably' lift 2,000# should be available at the building site to unload tire bales. This same tractor/skid-steer w/forks can be used to stack the bales in their final position.
Q. Will one of these houses really be ‘free’ of energy costs? How much heating do they really require? How hot do they get in the summer? How cold in the winter?
A. In many locations in the United States the solar insolation and climate is such that enough heat can be extracted from solar rays and stored in the inherent thermal mass of the house to make it capable of sustaining comfortable temperatures continuously, year around. Our house maintains a minimum winter temperature of 63ºF, with up to 75ºF during winter days if the sun shines that day. Standing under the sunny windows on that day would be very warm, indeed, at upwards of 100ºF. And this with an outside temp of 20ºF. We do have a small woodstove that provides a flash of heat on snowy evenings or on 'Arctic front' days.
Q. There have never been any of these built around where I live. How can I, or will I be able to get a permit?
A. There is a substantial engineering document available that makes refusing the use of rammed-earth-tire walls by building officials for structural reasons, almost impossible (Dennis Weaver Residence, Engineering Study; Rammed-earth Tire Walls; by Tom Griepentrog of Buckhorn Geotech, Inc., Montrose, CO, obtainable from Solar Survival Architecture or Buckhorn Geotech, Inc.).
If you require a building permit, both a tire bale house and rammed-earth tire house will require a Registered Professional Engineer to approve the project (stamp the drawings).
Building a tire house in your neighborhood may not be possible for other reasons, however. If there is an Architectural Committee and/or Codes/Covenants & Regulations in place, there will probably be a plans review and there may be an arbitrary denial by the enforcing committee (Used TIRES!! Laying around!! No way!!). I have, however, made three applications for clients to Architectural Committees of Owner's Associations, and all were accepted. But be aware, the chance remains, that they might refuse your application.
Q. Why couldn’t I use poured concrete walls instead of used tires?
A. Well, you can use anything you like. Used tires and dirt are free, so there is substantial potential for $weat-equity using them, to say nothing of what using the alternative (‘normal’ building techniques) does to our environment during construction and for fifty years into the future. Then, there is the eventual outcome on our society of building without regard for future energy sources.
"Why chemically alter heavy materials with heat and great consumption of energy and then transport them long distances in order to construct buildings, when most of the structural material is underfoot at each site?" --David Wright, AIA - Environmental Architect, in his book "Natural Solar Architecture, a Passive Primer"
You can make 30 adobe bricks with the energy it takes to make one (1) concrete block.
Q. Do I have to use a ‘kick-up’ roof like Michael Reynolds’ “Earthship” designs, in order for my passive-solar home to work?
A. No, a properly designed and executed single-plane roof design will work better, in my opinion. This shape promotes both a leak free roof and unobstructed inside heat convection/air circulation, using all standard roofing hardware, i.e. standing-seam metal and gutters, as seen at: http://www.touchtheEarthRanch.com/Unruhroof.htm
The M.R. design creates a 'crease' for water to run East to West in a South facing roof. Thus, causing the water to change direction by 90º in the middle of the roof. Any roofer will tell you this causes 'leak stress', and considerably more chance of leakage than a roof that drains straight off, to say nothing of adding considerable complexity to the framing (drainage cricket is required with M.R.'s design) necessary to properly drain such a roof.
Q. What is “earth-cliff”? Can I use it on my house construction?
A. Earth-cliff is a term ‘invented’ by Michael Reynolds to describe a mode of construction whereby a wall (tire-wall) is built above the edge of the excavation for the home. As these homes are ‘dug-in’ to the hillside, there can be considerable savings in pounding of tires by using this technique.
NOTE: Earth-cliffs can ONLY be used where site soil is very stable (soils test recommended, if not required), as this ‘cliff’ holds the weight of everything above it and if it were to slump or cave-in, it would be a very difficult calamity to adjust, being as the whole house, roof and all, would fall in. An 'earth-cliff' can be seen in this picture, behind me where the wall I'm leaning on meets the 'cliff'. A tire wall is built on top of this cliff, thus saving the use of tires to build the wall below.
Q. Can I use unsawn log timbers on my roof like in the “Earthship” books? Where can I get them? What do they cost? What are my alternatives?
A. Un-sawn logs can be hard to find, or easy. When you do find them, they may range in price from FREE to $7/linear foot. Most saw-mills will have access to good logs. Forestry permits can be had in affected areas, for beetle-killed trees. If you are lucky, you live in a forest like we do. Remember, that logs used as roof members are ALL subject to UBC requirements on “structural lumber” (holds up the roof); “graded”, in other words, certified and stamped by a lumber/timber inspector. If your residence construction will require building permits and inspections, graded structural lumber is a must before the aware inspector will pass your roof framing. Many of the homes I have drawn plans for use "I-joists" as roof members, instead of logs; see: http://www.umass.edu/bmatwt/publications/articles/i_joist.html for the history and a lead-in to I-joists. In the I-joist roof, fiberglass batts are used between joists. I believe these joists to be a much better alternative than regular sawn lumber or unsawn logs, if the logs aren't available economically. Roof structure and passive-solar success are mutually exclusive.
Q. I live in a warmer, more moist climate, can I still use tire-wall construction? Will I be able to passively cool my house?
A. Tire-wall construction is valid anywhere you might build a house, especially in warmer climates. The thermal mass of tire-walls keeps the home inherently cool, much like a cave would. Windows are faced away from the sun in this application and buried perforated pipe(s) leading to floor registers in the house while skylights provide excellent vent convection and natural cooling is the result.
Q. I live in a colder, snowy, more Northern latitude, can I still use tire-wall construction? Will I be able to passively heat my house?
A. The concept is valid wherever it is applied. Depending on what the outside climate is; changes can be made in the design application that will make a tire house the best choice for almost any location. Passive solar can always add to any application, providing there is a daily sun exposure. In many ‘cold winter’ applications there will be no additional heating required.
Q. What do your plans tell me about photo-voltaic and other alternative systems?
A. All I suggest is where to put them. Otherwise, design of these systems is a separate responsibility. I can consult/opine on their usage and installation, however.
Q. Can I see a tire-bale house?
A. Several that I’ve designed are under construction by owner/builders, one is completed ( http://www.hagartirebales.com ). More pictures will be posted as construction continues. To see some pictures of a sequential tire bale house build, click here. NO RESISTANCE, what so ever, has been experienced by owner/builders from building officials/plan check, when they have applied for permits (the boys 'downtown' seem to like the concept).
Q. Tire bales are just rubber and steel belts, are they as massive and will they work the same as rammed-earth tire walls?
A. Manufactured rubber has exactly the same weight per cubic foot (95 lbs.) and specific gravity (1.52) as packed earth. Hence yes, tire bales (compressed rubber and steel belts w/less than 5% air) will work the same, have virtually the same thermal mass as rammed-earth tire walls, only are twice as thick while taking roughly 10 times as many used tires from the tire dump.
Q. What are the floors made of? Do I need to insulate under them?
A. The floor of a passive-solar home is the largest potential for thermal mass storage, naturally available at every site. Floors should be made of a thermally conductive material (as opposed to insulative, i.e. no W-W carpets w/foam pad) such as flagstone, slate, or Saltille (Mexican) tiles over poured concrete or adobe. I recommend a 2-3” layer of ¾” river-rock over the sub-floor with a 6-mil plastic film between rock and concrete pour or adobe. The idea being to keep sub-soil moisture from wicking up through the concrete/adobe and leaving mineral deposits (white chalky blotches) and muddy spots. In colder climates, vertical insulation should be installed around the sub-surface perimeter of the exposed foundation walls.
Q. How does electrical wiring and plumbing work in a tire house?
A. Tire walls (either rammed-earth or tire bale), before they are filled-in with plaster, have lots of grooves, slots and spaces for conduit runs, J-boxes, stapled-in Type UF wire (if no conduits are used) and switch boxes. In other words, wiring is done using standard electrical practices, before finishes are applied. Same way with plumbing drains and supply lines, which are installed before floors are poured. Any other features would be exclusive to each design.
Q. How big can the rooms be?
A. Room sizes are more-or-less arbitrary. The success of a passive-solar home is based on a larger group of variables than the size of rooms. One of the largest variables being personal comfort levels.
Back to room sizes, they can vary widely, esp. using the tire bales. This being because the structural stability of tire bale walls allow the entire place to be free of internal walls used as bearing walls, i.e., their 5’ width/thickness, allow free-span roofs. They don't need the roof framing to support the E-W stability of the 'finger' walls as necessary with the rammed-earth tire-wall structures (as seen in "Earthship" Vols. I, II, & III). This makes the tire bale houses more easily and inexpensively framed.
In my experience, the maximum room width practically attainable in a rammed-earth tire-wall residences (as seen in "Earthship") with reasonably priced, available building materials, i.e. using 16” I-Joists with a 50# snow load; is 26', wall center to center. Maximum depth of rooms is a function of climate, solar gain (days of sun) at the site, "sunscape" available at the site, thermal mass storage directly available to heat from the window array and lastly; window size to available floor space ratio.
Q. What about hail? Won’t the slanted glass break?
A. Wherever large sheets of glass are exposed to wind, ‘small’ projectiles and the elements, they should be tempered glass and in most places, it's required. Tempered glass is very difficult to break and when it does, it doesn’t break into shards of cutting pieces, but rather into thousands of small, almost ‘granular’ pieces. The slanted glass indicated by many passive-solar designs must be tempered glass. Our window array has withstood 2-1/2” diameter hail, so far [crosses fingers, knocks on wood].
Q. I'm not sure I understand how you vented between the top of the insulation and the roof sheathing. In the “Earthship” book, it shows the 2 layers of stiff insulation, then the roofing material. How can that be vented?
A. The ‘hardboard’ insulated section of the roof, as seen in "Earthship vol. I", needs no ventilation. That section is constructed like a ‘normal’ commercial roof, with no air in the roof assembly. Whereas; in a ‘normal’ residence (where there is air in the roof assembly) the air below the roof and above the insulation, is vented with outside air via the ridge vents and soffit vents (under the eaves).
As in; the ‘greenhouse’ portion (“kick-up”) of the typical “Earthship” roof, is what needs ventilation. Michael Reynolds tries to avoid this by attempting to fill cavities with fiberglass batts. This design in a cold climate, is doomed to eventual failure, as fiberglass batts collapse and compress with time, causing micro-climates between the roof sheathing and the insulation. When this happens, on a cold day (<20F), condensation forms in them due to the cold surface next to the warm, moist air from inside. This condensation may freeze, but eventually thaws and drips, causing further decay of the fiberglass insulation, thus increasing the size of the micro-climate, on and on. Any gap causing an air-pocket is a problem unless it's either vented or insulated from cold outside.
Q. How do you feel about the Solar Toilet in an "Earthship®" designed by Michael Reynolds?
A. I think it was a well-intentioned idea that smells bad. Otherwise, if you live where there is adequate soil and percolation for a standard rural septic system, the standard system makes a lot more sense to me. Especially when you have your in-laws as guests and the sun isn’t shining. Unless, of course, the "solar toilet" is outside the house.
Q. What about composting toilets?
A. Many have National Approval for usage in any residential structure, but expect some hoops to jump through. As an example; in my county you can install one in a new residential construction, but you have to plumb-in and install a ‘standard’ solids separator tank and leach-field system, even if you never use it; for the convenience of "future owners”.
Q. Is it possible to have an Earthship that doesn’t smell moldy and musty?
A. Yes, if you don’t have many/any plants that require large amounts of wet soil be in the house. That "earthy" smell is molds and bacteria busily decomposing soil.
Q. Are the tire bales attached to the ground, are they free standing, how are they held together?
A. The bales are stacked "free-standing", alternate lay like bricks, wherever possible, with no connection to the ground or each other, other than gravity (each weighing ~2,000#). Aside from this, all exposed bales are wrapped with 1) moisture barrier [insulation in some places], 2) stucco-mesh (hi-density chicken wire) and 3) a minimum of 2" of stucco plaster, mud plaster, adobe or shot-crete.
Q. What happens when a tire-bale wire breaks?
A. In tests on a single bale, the first wire break usually occurs at around 150,000 lbs. The tests I have seen have been performed in the unrestrained-bale state, allowing the bale to flex in four directions, but still works out to roughly 6,000# psf. In a residential application, as seen in my drawings, bales are stacked end-to-end, wires running with the length of the wall, thus preventing flexure in the direction of the wire-lay and removing much of the stress from the wire(s).
Further, as a note of interest: Once a tire has been compressed into its position in the bale for a couple of weeks, it "forgets" that it was ever a tire, hence, if a wire did break, no "explosion" of rubber occurs as a result. All exposed surfaces of the tire bale walls will be wrapped with moisture barrier, screwed on nailed-down metal stucco lathe and at least 2" of adobe mud/mortar filler/plaster and/or stucco finish. Finish can be applied by machine (as in shotcrete) or by hand. All/any ends where bale wires might be exposed (but still stucco & stucco-mesh encased) are non-structural.
At each termination of a framed wall and a tire bale wall (both horizontal and vertical), there is an 8" thick x 2' wide (minimum), reinforced concrete bond beam that has been poured in place, contiguous with the tire bale wall. <see: http://www.touchtheEarthRanch.com/baleconc3.jpg>
Q. What do you cover the tires with?
A. The tire walls are covered with any plastering technique. "Shot-crete" may also be used, if you can afford the initial cost. A considerable difference in time required should be considered here. Filling the spaces between tires is MORE WORK than filling the tires in the first place, in my opinion. Where the tire-walls face the outside elements, i.e. water & freezing; the wall should be be prepared and stuccoed. I.E., first a moisture barrier (2-layers 15# felt, or equivalent) is attached, stucco-mesh or metal lath over that (with screws or nails through aluminum roofing disks), then stucco finish in three layers. Stucco should be applied when temperatures don't go below freezing for 36 hours after application. If this procedure isn't followed, eventual cracking will occur.
Q. Can I get financing for my tire house?
A. Financing a tire-house construction is difficult if not impossible. Financial institutions aren't in business to take risks. To them, a tire-house is an unknown quantity. It doesn't show-up on their mathematical models, and there are very few comparables, so they have no way to evaluate it. Hence, it won't even fall into their realm of consideration. They may, however, finance one that is complete or partially complete. Actually, this fact is a hidden BONUS!!
Why? The fact that this house is built (mostly) of trash, 1) secures that it won't be stolen during construction, 2) it makes it affordable for the average person/couple to build as an alternative 'hobby', 3) it's buildable by anyone for cash, making the resultant home and its owners, 4) free from a mortgage; hence giving the owners 5) time to spend gardening and playing with their children and grandchildren 6) without pressure to make enough money to pay the heavily profit-laden mortgage, thus 7) allowing the owners freedom of expression and comfortable lifestyle they'd only dreamed about before. Dirt cheap houses; built for cash with trash!!
It takes a while to get off the "I want it now" train. It looks like a good ride; after all, 'everyone' takes it (don't they?). But the price for the ticket is more than 'they' tell you when you sign-up for the ride. It took me getting on board and riding for a while before I realized that I couldn't get off; to say nothing of the three times as much energy required of the passenger(s) simply to support the train itself (huge banking overhead/profit). They didn't tell me before I got on what that extra energy requirement would do to my family/lifestyle/culture/civilization, either.
Q. Can I get insurance on a tire house?
A. Yes, you can. Ours is insured for fire damage and theft of contents, etc. No problem. I have Farmers Insurance Group fire, theft, etc. homeowner's insurance, and its even reasonably priced.
However, I far prefer fire prevention to insurance. After all, insurance doesn't protect your house, really. It only does its job after your house is burned. For REAL PROTECTION, i.e. fire prevention, have a look at www.firegel.com
Q. Can you use drywall over the tires?
A. No, drywall would require a space between the tire-wall and the dry-wall surface. This space, and the drywall itself, would constitute an insulator between the tire-wall and room-air. The tire-walls inherently provide thermal mass storage and insulating them from the ambient air temperature of the interior could result in the house being too hot in the summer and too cold in the winter.
Q. Can I have a two-story tire-built home?
A. In short, no. Attaching a between-stories floor is not practical for numerous reasons: First, there is the thermal problem. Solar window arrays collect very large amounts of heat, 2-3 times what is required in a "normal" house, so if there isn't sufficient thermal mass storage in the room(s) they face, it will become extremely hot therein. Not having the floor as a thermal mass sink for this heat will cause the upper story to be too hot whenever sun is shining, and too cold when its not. In other words: It would be thermally unstable. Secondly, although the lower story will/could function properly, thermally speaking, it too has a problem: That of ventilation. Passive ventilation would be difficult to achieve, as the normal path is obstructed by the upper level floor. Thirdly, the attachment of the intermediate floor structure to an ongoing tire wall is problematical. Lastly, a tire wall of the height necessary for two stories is unstable. The maximum number of courses in a rammed-earth tire wall is ten courses (8' 4" maximum).
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"When I began my earth rammed tire home journey in 1994, I was daunted by the cost of plans from the "experts". Then I heard about Michael Shealy and that was my first big step in the "right" direction. Not only did Michael do up plans for much less cost, he personally came out to my site and gave me and my helpers a lesson on tire pounding. He continued to be at the other end of the phone when I needed advice and his encouragement and enthusiasm was contagious and provided much inspiration. It was a special honor to have him attend my open house in 2006 in my "finished" tire home."
by: Pascha M., Home Owner/Builder
About Michael Shealy
As an Architectural Designer, Michael provides residential designs using hybridized practical building techniques. These methods are beneficial to the Earth and the end user, employing used tires that are a highly durable, easily obtainable/free building material that removes problem waste from the eco-cycle.