Timber is a low pollution material - in felling, processing, use and disposal. Preservative treatment with copper salts are needed for timber in some cases. The treatment is carried out under properly controlled conditions. But in contrast to other building materials it does not contribute to the "sick building" syndrome. This is often caused by moisture penetrating and staying in the walls of houses with masonry external walls.
Life cycle and burden on the environment.
The expected life length of the house - and the time before major repairs are necessary - is an important environmental as well as economic issue. A house that works well over a long period of time will naturally be a lesser burden on the environment than one that needs frequent overhauls. An ordinary house using plastered concrete blocks as the external skin will need repainting with very short intervals if it is to stay looking good. A timber panel of dense Scandinavian timber that is treated with tung-oil would need maintenance every 4-10 years mainly for visual reasons. The concrete wall usually needs major repairs after 30 - 50 years. The effects of water and frost can cause cracks and movements of the concrete blocks, which makes the plaster fall off in places. The pressure treated timber cladding is made of close-grained pine with high levels of natural resin. It is generally estimated that the cladding will last for 100 years in a maritime climate.
The fact that different types of materials, such as brick, PVC, aluminium and wood shrink and expand differently is important for the maintenance and the life span as well. In a house built of a mix of different materials, such as a regular cement-block house, the following happens: Different parts of the house contracts and expands variously. Problems with cracks and leaks will occur. A timber house won't develop these problems because the whole structure moves in the same way when temperature and moisture levels change over the year.
Peak-oil is looming - Energy savings in the running of a house
By far the most important environmental aspect is the enormous saving on energy that living in a passive . Houses consume almost two thirds of Irelands annual energy bill. If regular houses were insulated to current Swedish standards, heating bills would be cut by 90%. The average outside temperature in Ireland is +10°C. The desired inside temperature is about +20°C. The difference is only 10°. In a well built house it does not take much energy to make up this difference. In Sweden, the difference between inside and outside temperature is often between 30° and 50° and people manage - because they just had to develop better houses. With better built houses, less waste of fuel and money would take place simultaneously with reduced air-pollution and increased standard of living. (all rooms habitable and relatively warm at all times) .
2003 Irish building regulation. The 2003 regulation improve the energy performance standards considerably. It remains to be seen if the concrete-building industry can achieve the new required standards in practice! Scandinavian Homes Houses perform twice as well as the new building regulations in theory and in practice.