Green Homes: The New Gold Standard (Beyond Net Zero & Passive House Design)

The newest Earthship green home design would seem to be the best performing home design overall, beating typical Net Zero or even Passive House designed homes. However, it would be even better if 50″ or 60″ thick straw bales were used instead of tires and rammed earth for walls.

Firstly, rammed earth of any kind, including pounded dirt tire walls, require either energy intensive machinery or intensive labour: both add to cost.

Major considerations for earthship design include: DIY capability, universal adaptability to many environments, excellent environmental standards, use primarily recycled or natural materials, ultra energy efficient, highly if not completely self-reliant in terms of energy, heating, cooling, water and food, and lower cost. So far, the earthship designs, up to an including the latest Encounter design, succeed brilliantly in all criteria, except for cost.

The still high cost is mainly due to high labour requirements; which must be viewed as a major design weakness, unless you are using entirely volunteer labour, or it is entirely a DIY build, and you like pounding tires.

Straw bale construction increases insulation ten-fold PER INCH of wall thickness, or 50- to 100-fold over a 2-3 foot thick tire wall; AND is a non-toxic, carbon sequestering, natural, recycled agricultural waste product; AND is simple, easy, DIY capable, strong, durable, tested and approved in many regions for building codes; AND lowers costs by lowering dependence on expensive energy-intensive machinery, or LABOUR.

No comparison, no contest.

Why continue to insist on (rammed earth) tire walls? They work. But straw bale increases insulation dramatically while greatly reducing labour and saving on cost.

Rammed earth, with or without tires, gives a thermal insulation R value of 0.2 per inch of wall thickness. Straw bale gives R-2 per inch, a ten-fold increase, even before berming, which should be done in any case.

A two foot thick tire wall gives R 0.4. A straw bale wall 50″ thick gives R-98. Do the math. And cost is lower with straw bale due to savings on labour costs. Lower cost plus superior performance means straw bale is the clear undisputed winner.

Again, compressed straw bales are cheap, carbon sequestering, highly resistant, with plaster, to fire, flood, earthquakes or storms, insects, rodents and pests, and are now largely an agricultural waste product, since factory farming has eliminated its traditional use as animal bedding.

I am sure we can use recycled tires, bottles and cans in better ways – such as soles for footwear, fabrics made with recycled plastic and rubber, or interior and exterior walls that do not require insulation or thermal resistance.

Rock wool or fibreglass insulation, mineral wool, blown cellulose (newsprint), spray foam and rigid foam, are either high in energy requirements, fossil fuels or carbon emmissions in production, or toxic to people, animals and the planet, and thus should be eliminated from building codes and norms as utterly unacceptable.

Alternately, rammed earth, tire walls, and cob, must be viewed as basically non-insulating materials, and to be avoided, or used only when combined with serious insulation of R-50 or better.

The only remaining options I know of are truly green or straw bale SIPs, and straw bale itself.

For the main exterior walls and envelope of a new green home, 50-60″ thick straw bale walls, with R 50-120, coated with beautiful natural plaster or adobe, should be considered the new gold standard.

JTR,
July 29, 2020

3 Responses to “Green Homes: The New Gold Standard (Beyond Net Zero & Passive House Design)”

  1. jtoddring Says:

    A straw bale / plaster dome, underground….. Hmmm….

    This is not straw bale; however….

    Brilliant design. I love that it’s underground, but brighter inside than most homes – and there are no hard edges or straight lines!

    Like

  2. jtoddring Says:

    Adobe home: gorgeous, natural, and 1/3rd of typical, standard stick frame construction, at $100/sq ft CDN ($60USD).

    Add straw bale/stucco exterior for R-50 insulation on walls floor and roof, then berm earth, for super-insulation. Incorporate passive solar design, and an attached solar greenhouse, as in earthship design, naturally. Then you can have an off-grid, net zero, healthy, gorgeous, natural, deep green home, which requires zero fossil fuels or electricity to heat or cool, and still costs 1/3rd of an eco-destructive, energy hog, planet cooking, toxic, boring standard stick frame house. Is there any comparison? Of course not. It’s a no-brainer.

    Like

  3. jtoddring Says:

    Why adobe? Here’s why.

    http://arizonaadobe.com/faq

    Like

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