We poured the upstairs concrete floors today. We’d originally planned on using poured earth (the “dirt floors” mentioned in prior media coverage), but the installation cost proved to be much higher than concrete and therefore prohibitive. They both serve the function of thermal mass – storing the sun’s heat from the day and releasing it slowly. From an embodied energy standpoint the concrete is less desirable than the earthen floors, but on the other hand concrete is a more durable surface (because it is harder, which some will say makes it harder on the feet than earthen floors). There have been a few things throughout the project where cost has forced us to compromise on our ideals—it’s definitely a bitter pill to swallow.