Building with Straw
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Building with Straw






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Building with Straw Building with Straw Presentation Transcript

  • Building with Straw Straw bale, Cob, and Light Clay Construction Alison Ray 20 September 2004
  • An experience with straw: Bioconstruindo 2004 Heidi: Queen of the Strawbale Pile Brazilian Cerrado, Rippin’ the Curl
  • Bioconstruindo: bamboo geodesic dome, vigas reciprocas & ferrocement caixa de agua
  • Quick History of Straw Bale Homes
    • 1800s – Nebraska: Settlers
      • Lumber expensive and sod too precious but straw was extremely abundant!
    • Invention of horse-powered baler in mid-1800s and later steam-powered made home construction faster and more efficient
    • Warm in winter and cool in summer, not just a temporary thing
  • Constructing a Straw Bale Space
    • Straw bales are stacked like blocks to form the walls of a structure
      • Load-bearing walls
      • Infill for post and beam
    • Straw bale walls are highly insulative (up to R40), sound proof, and when plastered resistant to fire, vermin, and decay
    • Works great in combination with cob
  • Laying and sewing the bales
  • Binding the bales with wet cob
  • Nearing the top
  • Natural plastering: cob and clay
  • Almost done
  • Quick History of Cob
    • Cob is an old Devon word for ‘mud wall’
      • Cob has been Devon’s traditional construction material since 14 th century.
      • Traditionally, straw and dung, were added to the clay sub-soil to reduce cracking
    • Cob can last for many years so long as it does not accumulate moisture
      • Some houses in England are 600 years old and still standing
  • Cob Construction
    • Cob is a mixture of clay and sand (earth), straw, and water
    • Cob walls have no structural elements
    • Natural plaster or rendering must be applied to prevent moisture
    • Cob is favored for its freeform quality
    Our cob bird-bench Mixing the clay, sand and water takes muscles!
  • Advantages of Cob
    • Abundant, inexpensive and replenishable material
    • Free-form, creative and artistic
    • Easy to do (and fun!)
    • Structurally more stable than conventional homes to earth quake
    • Cob is a flexible material that moves with the Earth’s movements while staying together (allowing for rounded, natural shapes
    • Provides thermal mass, storing sun’s energy and releasing it at night but also cool and shaded in the day
  • Cob socials! Fun to dance and play with the earth while creating functional art!
  • Inserting a window into a cob wall Forming cob bricks from the wet material
  • Cob wall with tree stump decoration Cob Giant (oven and bench) Yes, it’s the same picture, but look at the cob this time!
  • Taipa Leve: Light Clay
    • German tradition for over 400 years
      • “ Leichtlehm” or “Wattle and Daub”
    • Timber provides most of the load-bearing structure
      • straw, earth, woodchips, sawdust or any material provide insulation and infill
    • Panels created to be independent so houses could be easily deconstructed and transported
  • Using Light Clay Construction
    • Loose straw or other material is coated in a clay slip then tamped into temporary forms for infill of a wood frame
    • The material will dry about 1” per week, an applied plaster prevents moisture from entering the wall
    • Panels are light weight, insulative, non load bearing and great sound proofing
    • This technique can also make sawable construction blocks
  • Creating light clay walls
  • Tamping down the walls
  • Building the Walls
  • Natural Building is good for the environment, for human health, and community-building, but most of all… it’s fun!!