Octagonal straw bale house at Castlemaine. This very interesting home is in the spectacular "nuggety" country outside Maldon and is notable, apart from the challenge of many oddly shaped triangulated rooms, for a thousand mud bricks in the central atrium adding to the great thermal mass of the polished terra cotta slab and lime rendered  straw bale walls. A conventional oblong dining room extends to the west from the main geometry. Solar and wood heated hydronic floor heating is very effective and the house remains comfortably cool through summer too. Stone or earthen walls are perfect as internal walls for the thermal mass they provide to stabilise temperatures year-round. For external walls... stick to straw bale.