Tenets of a healthy home
This stunning Oratia home was built in line with the principles of building biology and ecology.
When the Building Biology and Ecology Institute (BBE) set up shop in New Zealand in 1990 it added another dimension to the existing eco building approach, taking into account the biological effects of the buildings we live in. So what is the distinction between biology and ecology all about? In a nutshell it is about the twofold impact of building on the environment (ecology) and on the health of people (biology).
The principles of building biology and ecology have been incorporated as much as possible in the Oratia house featured here. The challenge in the design of this home was to enable three generations to comfortably share the space by providing a 3-bedroom home and a minor dwelling to be used separately and/or communally.
With regards to creating a healthier indoor environment the fundamental design choice was passive solar design with large, north-facing joinery, provision of thermal mass (concrete) and a high level of insulation (140mm thick walls, double glazing) as it helps create a relatively balanced ambient temperature level throughout the year. In order to prevent overheating in summer shading devices are incorporated in the roof design to the north and the use of clerestory windows facilitates a good air flow and ventilation by using the stack effect where rising warm air draws in cooler air from a shady side of the house. The double garage is positioned to the south of the house as a buffer to the prevailing cold southwesterly winter winds.
With the design providing for natural solar heat in winter, natural air flow for ventilation in summer, ample natural light and a dry and warm interior the basics of healthier living conditions were in place. Minimising the generation of pollutants remained to be looked at.
Low VOC interior finishes for walls and flooring are the major items in respect of cutting down on toxic out-gassing. The use of PVC items has been minimised.
The continuously warm and dry interior during winter means there is no suitable environment for the growth of mould and mildew.
Exposed timber flooring (plantation grown eucalyptus saligna) has been used in addition to the concrete floor slab, which cuts down on dust and makes for easy cleaning.