The Earthship at the End of its Life
What happens to an Earthship when it dies? All buildings do
eventually. What will be left is a flagstone floor (in most cases), glass panel
windows, some concrete filled with
cans and
bottles, wood framing
and beams, cabinetry, plumbing, cisterns, metal flashing and roof, and the earthen tire berm.
The flagstone will be reusable. It will just need chiseling
out. The glass could be reused intact for other projects, or recycled outright
if it is broken. The metal flashing of the greenhouse and the metal roof system will most likely be reusable or recyclable.
Plumbing probably will not be recycled due to health
concerns and deterioration of the PVC. The concrete filled with cans and bottles will not likely be good for
anything. The bottles and cans will likely break or be too encased in the
concrete for salvage or even recycling. The cabinets in all but the most
sophisticated Earthship are plywood, so there is no point trying
to save them. Those materials – about 10 dump truck loads worth – will most
likely be taken to the landfill. Footings and buttresses, if they are present,
will add another 5-10 dump truck loads. There is some possibility they can be
reused in non-structural landscape walls, though the presence of
exposed rebar, which rusts and causes the concrete to spall, will likely render
those unusable.
Concrete cisterns will also be discarded - another dump truck
load or two for the landfill… as will the raised interior planting beds –
another 2-3 loads. If the cisterns are plastic, chances are no-one will want to
reuse them because of deterioration, but maybe by the time they are abandoned
we will have figured out how to manage recycling them.
Maybe some of the wood that was covered with metal can be salvaged,
though likely not from the greenhouse, as it will likely be
rendered unusable due to moisture damage. The vigas, and the roof decking if it is solid wood, should be reusable.
Tires have a life of 30,000 years, so the berm, while it may deteriorate,
will likely be left to degrade and become a mini dumpsite of toxic materials
that may threaten the water supply. Or, the tires can be returned to the landfill.
We talk about aspects of the life cycle cost of Earthships throughout this book, breaking
down embodied energy and cost, including maintenance. We do not provide an
accounting for regional differences, as there are too many to calculate. We use
the U.S. dollar and local costs in New Mexico as the basis for our
calculations.
Life cycle cost is a comprehensive assessment, and since that
is not our purpose, we did not want to include a whole book about it here. What
we did want to do was offer an overview so that our readers could focus on the
parts of sustainability and life cycle cost that matter to them. If you do not
care about embodied energy, skip those sections.
What follows was the easiest way we could put the cost of the Earthship into perspective for
ourselves. We hope it works for you too!
Comparing the Earthship to a traditionally built home:
A three bedroom home of the same size as the Global Model Earthship
requires approximately 13,000 board feet of lumber for framing. If laid out end
to end, this would make a line of wood nearly 2.5 miles long! We would need 14 tons
of concrete. Sheathing would add up to somewhere around 6,000 square feet, as would
drywall. Roofing material, exterior siding, and insulation would cover an area nearly 10,000 square feet.
We would need 15 windows, 12 doors, toilets, kitchen sinks, bathroom sinks, cabinets,
fireplace(s) or stoves, and garage
doors. We would also need food, water, electricity, fuel,
and household products.
The Global Earthship still requires thousands of board feet
of lumber and vigas for framing. It needs 9 tons of concrete. The roofing
material, exterior stucco, and insulation would still cover an area nearly 7,000 square
feet due to extra levels of insulation required at the berm’s cisterns, thermal wrap, and tubes. We
would need 40 windows and 9 doors - double that of a normal home - since there
are two layers of windows and doors at the greenhouse, plus the same toilets,
kitchen sinks, bathroom sinks, cabinets, fireplace(s) or stoves, garage doors, etcetera…
as a regular house. We would pay a premium charge for the systems and their
maintenance and require backup power and backup heat, plus we would need special
soils for the greenhouse, soil amendments, and insect control. We would also
still need food, water, fuel, and household products.
Does the Earthship model actually end up increasing
financial and material requirements? The math suggests that the answer to this
is yes.
