Sustainable building used to be the norm in our society, before the advent of cheap and readily available transport and finance. It was an essential aspect of everyday life, using cheap or free locally available materials and labour. These materials were usually obtained, processed and constructed without any adverse effect on the local environment or the global carbon footprint. Straw thatch, Wattle and Daube, local stone, mud and horsehair (though it was usually cowhair) plaster - all these materials were local, sustainable and an endless supply.
The people who finished the houses were often relatively unskilled and usually the owners. You can see examples of professional plasterers' work where they have been instructed to 'make it look rustic'. The result is often obviously fake. What they should have done is either employed a novice or had a go themselves, as the finish they were looking for was that achieved by an unskilled person doing his or her best! It is these characterful houses and cottages with all their imperfections that the tourists photograph, not the perfectly finished house on the estate.
The self-builder can often save a lot of money by 'having a go' - as a very wise man once told me "if you really do your BEST, it won't be that bad". Start in a place where no-one will notice and practise! If it goes wrong you can always do it again or call it a 'Cottage Feature'!
The main factors that can be used to judge whether a material is sustainable or not today:
Most local builders will also not be familiar with working with sustainable local materials and may not even understand why you want to do so? They may not even have the skills required, so make sure that you see examples of their work using the same materials BEFORE you contract them. One Straw House build I know finished up doing most of the work themselves as the builder made such a mess of the adobe/hemp plastering. It looks brilliant by the way.
Again, ask at your local Council for recommended contractors.
Some of the best features we have seen have been made using recycled waste materials - and imagination! That spare York stone flag and cut-off oak beam end could make a stunning pedestal for a free standing bathroom basin? The possibilities for creativity are endless - just think 'Outside the Box'.