The Thick-Skinned Regional House is a prototypical prefabricated 400 square-foot house for 2 adults, to be adapted to dense urban settings in various climates. The house consists of two distinct systems: a universal starter frame (structure) and two “plug-in” walls (skin) to manage daylight and thermal exchange within various climates. The starter frame is composed of ribs which are CNC routed from local renewable wood and the “plug-in” walls consist of cubic modules, half of which are filled with a local and readily-sourced regional material, and the other half act as shelves for personal belongings in addition to allowing daylight and views. Adaptability of the house is core to its success, as it is meant to respond to any climate it may encounter with ease and grace.The thickened structural frame composes the floor, ceiling, and two of the walls. The kitchen, bathroom, storage, and services fit within the thickness of the wooden frame, to free up the interior space which maximizes flexibility in the compact space. The thick and varying frame creates an interior landscape which subtly allows for domestic behaviors such as sitting, eating, writing, lying, and bathing. The ceiling also varies to suggest spatial divisions and allow for storage. By providing the minimum division of space via the slightly sunken alcoves, the occupant has the freedom to change the program or function of each area depending on varying needs, time of day, and seasonal changes. Each alcove follows a uniform module based on a typical unit which accommodates a sleeping area for two. This unit is then used to set out the rest of the interior space. Thus, the fluid plan allows the lifestyle of the occupant to dictate the use of floor space, rather than vice-versa.