Earth walls have been around for thousands of years and successfully stood up to everything the elements threw at them.
Walls made of earth come in different forms: from clay bricks (fired or sundried), over rammed together with large hammers (in the middle of a timber sandwich or in between old tires as so-called Earthships) to clay being mixed in sand, straw, and water pressed together to form the walls. We have all seen them.
Earth walls in New Zealand are required to adhere to the following standards:
NZS 4297:1998 Engineering Design of Earth Buildings (Specific Design)
NZS 4299:1998 Incl Amendment#1 1999 Earth Buildings Not Requiring specific Designs
NZS 4298:1998 Incl Amendment#1 2000 Materials & Workmanship for Earth Buildings
Note: All standards are available on the Standards New Zealand website.
What can we do with earth walls?
Interestingly, though earth walls have proven themselves over thousands of years in earthquakes and all possible weather conditions, earth walls are not very common today. Further, the base material clay is often comes with the site. Environmentally earth walls are fantastic, if the soil from the site is used and no mining, production or transportation process is necessary.
Earth walls can also have several different shapes; round, square, small nooks built in for storage and even furniture like a couch can be built in. The look of earth walls is not everyone's cup of tea, however for lovers of natural materials, earth walls are only matched by log or straw bale homes.
Advantages of earth walls:
The material is often free of cost available on site
Much of the work can be done by the owners if they wish to
Natural materials used which are healthier for the occupants and assist regulating temperature and moisture
The walls are fire-resistant
Resistant to termites
Disadvantages of earth walls:
Time intensive to build
An overhanging roof is needed to help the walls stay dry
Additional insulation may be needed to stay warm recommend
Walls are very thick with a minimum of 280mm required by standard NZS 4297:1998 Engineering Design of Earth Buildings (Specific Design)