Brandon Smith (Redwoodtwig)
From a permaculture point of view, the house is home to people, animals and insects that harvest various kinds of crops in the rest of the garden. Most permaculture operations make a big deal out of natural building materials, citing the lessened impact on the global climate since large factory operations are not required. Straw bale houses for example, only require the tractor that plants and harvests the straw and bales it. A stick built house requires cutting trees, a brick house requires a brick factory, and so forth.
However, since there was already a house here, it seems to me that tearing it down and replacing it with something more permacultury adds more pollution that simply keeping what's here in decent shape. In any case, going "off the grid" is not an express goal in this permaculture project, so perhaps it's not really permaculture.
The contractor who built the studio addition had previously built various kinds of alternative homes in California, including straw bale. In his experience the costs in dollars is about the same in the end, balancing labor and materials across the different methods.
In any case the entire exterior of the house provides various kinds of environments for plants. However, plant desires and the requirement to maintain the house means that some plants, such as the English Ivy that was planted long ago on the west side has to go. And on the south side, there is a wonderfully warmer and calm place in the winter. The study of those areas is in the respective yard area folders.