The Philosophy
Natural (or sustainable) building appeals to people who are concerned about climate change, affordable housing, energy costs and resource availability. Natural building provides solutions in all these areas plus allows you and your family to live in a healthy chemical-free home that you may have built yourself.
If it's not affordable ... it's not sustainable!
What's the Difference between Green Building and Natural (or Sustainable) Building?
Natural Building Choices
The building materials used, the building’s design and how systems are integrated are all based on the buidling’s site, geographic location, and climate information. Systems may include power generation, water collection and re-use, heating, passive solar design, resource recovery, house shape and space design. By assessing what you have on a site-specific basis, you design an appropriate home using the most cost effective and natural materials.
Designing a Natural Building
One of the most important aspects of natural building is designing a structure that reflects the needs of its inhabitants. By identifying needs and space requirements one can combine function and beauty. Building small is the biggest step towards a sustainable and affordable home for your family.
Structural Lightweight Insulated Cob (SLIC)
Structural- Testing is done by crushing test cylinders in the same manner as concrete
- Our samples have come in extremely high with a value of 1.25MPa (mega Pascal)
- Test samples fractured in a perfect cone. Even after failure no visible cracks could be seen. This suggests that
even after failure from an earthquake the cob may maintain the structure and still hold up the roof.
Lightweight
Insulated
SLIC System
- All cob was mixed with a rototiller using only 24 l of gas
- Increase in efficiency (speed) of 500% over traditional foot mixing of cob.
- No sifting of materials
- More straw can be added to cob
- Mix is 30% clay, 30% sand, 30% pumice and lots of straw
- Cob pit is a slight depression in the ground with two sheets of thick plywood in the bottom.
- Rototiller
- Ours is a 1962 5HP Gilson with dull blades (very important)
- Our rotating blades are on the front of the rototiller and we took off the wheels and put the tilling bar down in the rear. This tilling bar allows the entire beast to be pivoted up and down to allow the straw to be left behind as it builds up and to facilitate turning and rotating.
- Basic Method
- Add straw first to cob pit
- Add clay and sand on top of straw
- Mix dry
- Add pumice and mix some more
- Add water
- Add more straw
Engineering/Seismic Wall System
Seismic Walls systems developed by our Engineer Kris Dick from Building Alternatives- Method for using diagonal tension members (cables) to tether the foundation to the concrete bond beam
- Compressive strength of cob can easily be measured (see below) but the tensile strength is more difficult to measure. Tensile strength is how strong the cob is when being pulled apart from an earthquake.
- Engineers need numbers in order to stamp the plans. We are hoping that with the very strong pumice cob (see below) that future engineering of load bearing cob structures will not require as many tension cables or perhaps something like bamboo instead.
- The diagonal tension cables force the cob into compression rather than tension during an earthquake. Cob is very strong in compression.
- Bond beam is 4 inches of reinforced concrete that sits on top of the cob walls all the way around. Purpose is to distribute the load of the weight of the upper story and the roof and to provide attachment for the cables from the foundation.
Rain Water Harvesting
Composting Toilets
Grey Water
Natural Plaster
High fly-ash concrete
click here for engineering dataFabric Form
see fabric form- Less waste
- Less wood for forms
- Easy to make curves
- Save money
