But I can tell you that it does concern-

• how the building connects or impacts on the site and the sensitivity of the project to it's surroundings
• the choice of materials, how are they manufactured, and their continuing use after this building (sometimes known as 'embodied energy')
• the use of energy, is it renewable, is it generated on site?
• how well the building relates to the landscaping
• has the garden design considered shading and solar gain, is it water efficient, does it grow it's own produce?
• what is the long term impact of the project on the site and surrounding sites?

It is a difficult task to determine whether a home is sustainable or otherwise, it might rate well for certain aspects but not on others. With an existing building some of the above criteria will have already been taken out of your hands. The building may be poorly located, or have been constructed with materials that do not provide good thermal mass.

When looking at your own home I would suggest addressing at the areas that you are most passionate about first, or that your budget can handle. Is it the garden, a lack of insulation or shading, or adding water saving features? The list could go on and on...
Accept that there may only be so much that you can do, but do what you can, and enjoy the process. Know that as well as adding to the pleasure you get from your dwelling you are also reducing your impact on the earth.

More soon on sustainable construction materials- yes, we'll be looking at bamboo, glass, timber and even bricks, as well as strawbale, cobb and mudbrick.