An engineering class at CCAT built three types of natural walls for a greenshed using cob, clay-straw slip, and cordwood methods. The cob wall used a 2:1 clay/soil ratio but had issues with bulging clay. The clay-straw slip wall maximized sunlight and insulation with a 4:1 clay/water ratio and straw, but had problems with existing beams. The cordwood wall provided insulation using local cedar with a mortar of cement, sand, sawdust and lime, but faced challenges from a lack of labor help and wood shrinkage leaving gaps.

1. CCAT GREENSHED
Reviewed by: Everett Williams,
Jacquelynn Dufour

2. GREENSHED WALLS
• Engineering 305 class –Spring
2010
• Building with natural materials/
Low embedded energy
• Shared constraints
• Breathable materials
• Minimum upkeep

3. Cob Wall
• Act as a heat battery for the shed
• 2:1 ratio of clay/soil
• Mixed materials using burrito
method
• Issues with bulging clay

4. Cob Wall
• Cracks forming along edges

5. Clay-Straw slip Wall
• Maximize sunlight and provide
insulation
• 4:1 ration of clay/water and 3
bales of straw
• Clay-straw pressed in forms
• Issues with preexisting top beam
and crossbeam

6. Clay-Straw slip Wall

7. Cordwood Wall
• Provide insulation to shed
• Western cedar used for local
availability and rot resistance
• Mortar recipe included
Portland cement, sand, saw
dust, and hydrated lime
• Big issue was lack of labor
help

8. Cordwood Wall
•
•
Apply new mortar
Wood has shrunken
causing gaps

9. THANKS!!!!
Questions/more information
• http://www.appropedia.org/CCAT_greenshed
_west_wall
• http://www.appropedia.org/CCAT_greenshed
_cob_wall
• http://www.appropedia.org/CCAT_greenshed
_cordwood_wall