Foundations for conventional building have, to a large extent, a one size fits all approach regardless of the type of ground you are building on i.e. a concrete and steel foundation that works equally well on all types of earth and varies only slightly in its design. It requires little thought and has been proven to be effective. The cement in concrete provides the compressive strength, and the steel tensile strength to resist cracking. It does however come at a cost to both your pocket and the environment.
When building with earth your foundation needs to be well considered as the integrity of your building rests here. Decisions you make about your foundation depend on the materials you have available, the type of ground you have to build on and what carbon footprint you want to leave. The goal should be to create foundations that are hard enough, move uniformly and resist cracking for the walls above it. Foundations will always have a higher Mpa value than the walls, however it does not need to be excessive. A 4 Mpa foundation is sufficient for a 1.6 Mpa mud-brick wall, which most types of foundations are suitable for. Furthermore, if after levelling the site the undisturbed earth is hard enough, foundations may well be unnecessary.
There are several strategies for foundations depending on the type of ground that you are building on. In this blog post, I discuss the four types of ground, (1) uniformly hard, (2) uniformly soft, (3) hard and soft, and (4) clay, their challenges and several strategies you may incorporate into your design. The discussion is quite technical in some areas so I recommend that you read my three-part series on understanding earth first. Continue reading →
Passive solar design is the starting point of sustainable building. Once one understands the basic principles of using the abundant natural renewable resources at our disposal we become more creative in our approach to design, more in tune and observant, reconnecting us with the natural rhythms that surround and sustain us, if only we would pay attention. Sustainable buildings save money, reduce your carbon footprint and provide a healthy living environment, transforming buildings from consumers of energy to producers and forging buildings that meet our needs.
From a permaculture perspective, incorporating these aspects into the design of your home are excellent examples of several permaculture design principles. To mention the most obvious: Observing and interacting with your environment to make the most of the sun’s migration, catching and storing energy, using and valuing renewable resources and services, integrating functions and elements rather than segregating them and obtaining a yield from the planet’s most abundant energy source, the sun.
Passive Solar Design uses the energy provided by the sun and stored in the earth. First we need to look at how this energy is utilized by defining insulation and thermal mass and then look at the strategies of how to incorporate them into our designs.