Benefits

Fire

Most fires spread rapidly throughout a home via the wood framing in the walls. Rammed earth homes are obviously much safer than wood frame homes. Rammed Earth walls have a four hour fire rating (highest needed in most general building codes).

Fire tests to AS 1530.4 – 1985 on a 300mm thick stabilised rammed earth wall stabilised gave 240/240/240 for structural adequacy/integrity/insulative capacity.

Rammed Earth does not burn or evolve smoke or toxic chemicals as many other building products do.

There are well documented cases of old earth buildings having their roofs and fitments destroyed by fire, and the earth walls left standing undamaged and because they are simply too difficult to demolish, being used again as the solid basis for the rebuilding and refurbishing of the building.

“In Washington, DC, a formidable two-story rammed earth building, with walls 2 feet (610 mm) thick, was constructed in 1773. It stood at 1300 Rhode Island Avenue for two centuries, serving for a period as an embassy, and was demolished only when the land became more valuable for other real estate. It is said that the wrecking ball used in this effort was ineffective, the thick earth walls absorbing the shock.”

Earthquake

Rammed Earth Houses are engineered to withstand or reduce the damaging effects of earthquakes.

In Mendoza, Argentina, historical rammed earth homes with walls of 60 to 100 cm thick had enough resistance to withstand all earthquakes of the last centuries, whereas all modern buildings built of adobe or bricks collapsed.

Research in New Zealand also indicates that monolithic earth walls perform better under earthquake conditions than walls made of separate bricks or blocks.

Whatever the engineering design, each home is constructed to the highest standards of workmanship and quality control and built to meet the requirements of the New Zealand Building Code.

“The Church of the Holy Cross in Sumter, South Carolina, was constructed in 1850 of rammed earth and is still in use today. This impressive public structure, with its steeple and steeply pitched gable roof, has required relatively little maintenance over its 148 years.”

Weather

The lasting qualities of rammed earth as a construction material are apparent in the traditional buildings that have survived over two centuries of use.

As long as the soil is chosen properly with a small percentage of cement stabilising the soil, the finished walls will be as resistant to deterioration as the parent rock from which the soil came from, and in some cases even more so. We protect the majority of our walls with overhangs (eaves), as is prudent in any form of construction.

Strength

Our rock solid, durable, wall system of 350mm thick rammed earth walls give a true feeling of stability and permanence.

Rammed earth is very strong in compressive strength and can be used for multistory load-bearing construction.

Due to the elasticity of rammed earth (the ability to absorb shock) there is less need for steel in the walls than concrete as it is not so inflexible. This is evident when demolishing earth walls that refuse to crack into large blocks (demolition of earth walls is never an easy job!).

This inherent flexibility or elasticity is also the most important structural defense against earthquakes, as well as aiding in its impressive load bearing ability.

Indoor Air Quality

How healthy are the homes we live in?

The idea that commonly used building materials in our homes can adversely affect our health is a relatively new concept in New Zealand – and yet we live and work in buildings containing plastics, treated timber, paints and glues, air that is too dry or too damp and poor ventilation.

As a result indoor environments are created where the pollution levels are usually up to 20 times more toxic than outdoors leading to sick building syndromes and arguably headaches, allergies and even cancers. With as much time as we spend indoors as we do – we should be able to at least enjoy the home as a healthy and restorative refuge.

What is all the fuss about Indoor Air Quality? And what is it…
The energy crisis of the 1970′s prompted a trend towards making buildings more airtight. As a result, these “modern”, well-sealed homes have an air exchange rate of only once every five hours or longer. Problems with stale air are compounded by the thousands of chemicals from building materials that off-gas inside the house. Building Science tells us that the human body requires between one and two air changes per hour to maintain vitality, regenerate body cells and eliminate environmental toxins.

The typical modern home can contain a chemical soup of volatile organic compounds (VOC’s) like formaldehyde, xylene, isobutylaldehyde, vinyl chloride monomer, and other organochlorides, aldehydes and phenols from all kinds of manufactured products.

That “new home” smell is the telltale sign of VOCs – from many of the products used in the construction of your average new home. Glues, treated and composite timber, carpets and paints and finishes commonly have VOC’s. They are also standard components currently being used in New Zealand housing. We deliberately try to avoid materials which can off-gas dangerous particles. Healthy natural alternatives exist.

Non Toxic

TFEBC considers everything that goes into our homes for its impact on indoor air quality (IAQ).

We use natural materials like earth, sustainable untreated timber, wool insulation and plant oil finishes. We also encourage the feature of tiled or enhanced masonry floors for dust reduction (and thermal gain).

With the combination of appropriate healthy building materials and by having walls that breathe and control humidity – our rammed earth homes can reduce the total VOC concentrations, thereby providing excellent IAQ for healthy, comfortable living spaces.

Humidity

The air humidity inside rooms exerts a significant influence on the health of the inhabitants.

A relative humidity of more than 70% normally feels unpleasant probably because of a reduction in the oxygen intake of the blood in warm-humid conditions. Increasing rheumatic pains are observed in cold humid air. Earth homes have been shown in studies to have a Relative Humidity (RH) year-round of between 45% – 55%. (See breathing walls).

Fungus and moulds thrive in a damp, unventilated environment where the humidity rises above 70%. It is distributed around the house and breathed in by the inhabitants. This can lead to various kinds of pain and allergies.

There are a growing number of studies that link allergies, immuno-depression, and illness to the amount and type of fungal and mould growth in a home. By avoiding surface RH in excess of about 70%, fungus and mould will be starved of the moisture they need to survive.

Dust mites also love a humid environment (over 60% RH), so by keeping the RH below 60% in your home you will also be keeping down the dust mite population.

Allergies

Allergies such as asthma, hay fever and eczema are on the increase. About 20% percent of the general population suffers from allergies or asthma. In addition to the familiar outdoor triggers of grasses and trees, pollutants and allergens lurk indoors.

Our homes are likely to be far more comfortable for anybody who is sensitive to allergies or asthma. With little if any VOC’s, fungus, moulds and dust mites, walls that breathe and control humidity, and by offering people alternatives to interior components (ie; enhanced masonry or oiled timber floor instead of carpets) we can make a very conducive home for people who are prone to allergies and asthma. (A note about carpets: Carpets tend to hold any mould spores that have collected in the house, and they favour the growth of mould, especially if the carpet has been damp at some stage. Many methods of carpet cleaning will actually encourage mould growth by leaving the carpets slightly damp).

“Many building methods are detrimental to our environment and living standards through resource depletion, energy consumption and pollution…”

Building with rammed earth can give a boost to the planet. Our rammed earth homes are environmentally friendly and are one of the lowest environmental impact building systems that is commercially available today.

Rammed earth is an unprocessed, widely available building material with virtually no side effects associated with collection and use. Earth buildings avoid deforestation and pollution, and can achieve low energy costs throughout their lifetime – in the initial manufacture and construction, in their use as homes, and eventually in their recycling back to the earth.

Since rammed earth homes saves construction and energy resources, doesn’t pollute and lasts practically forever it is a wise investment in the future of the planet.

• rammed earth homes do not exhaust natural resources
• requires less energy to be produced or processed
• are built using simple machinery and human energy
• blends harmoniously with their surroundings
• production or processing is possible with minimal pollution
• contributes to sustainable development