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).