Where are new zealands cob houses usually at?

Answer 1

If by cob, you mean the houses made of material variously called 'adobe', or 'mud brick' or 'rammed earth', then these styles of construction tend to be confined to areas where suitable materials are available, and where the climatic conditions are suited.

For this technique of building, the locally available soils have to include fine sands or clays that readily bind well. And that the climate does not have much driving rain. Near the coast for example, the rain is often driving - driven by strong winds, and this near-horizontal rain will quickly damage a cob building. In less windy locales, it is merely necessary to have sufficiently wide eaves on houses as to protect the walls from more-vertical rain.

Obviously, if the wall is surfaced with a weather-resistant plaster, then the above objection no longer applies. This now is also the case for 'straw bale' house construction.