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WOFATI, an acronym for Woodland Oehler Freaky-cheap Annualized Thermal Inertia, represents an innovative approach to sustainable building, coined by permaculture expert Paul Wheaton. This building technique combines the affordability and simplicity of Mike Oehler’s earth-sheltered designs with Wheaton's focus on cost reduction and integration with the natural environment. WOFATI structures prioritize the use of readily available, natural materials, such as wood and earth, minimizing reliance on manufactured products and reducing the building's environmental footprint. Annualized Thermal Inertia, a key principle of WOFATI, utilizes the surrounding earth as a thermal mass, storing heat in the summer to warm the building during winter and retaining cool temperatures from winter to moderate summer heat, thereby minimizing energy consumption for heating and cooling. WOFATI designs typically feature large windows on the uphill side to maximize passive solar gain, further reducing energy needs. WOFATIs are intended to be situated on or near a woodland, embracing the concept of harmonious integration with nature. Notable examples of WOFATI structures, including Allerton Abbey and Wofati 0.8, can be found at Wheaton Labs in Montana.

WOFATI structures are characterized by a thoughtful design that prioritizes passive systems and natural, locally sourced materials. The "two-skin" system, composed of a double layer of polyethylene membrane, encapsulates the earthen roof, providing a durable and waterproof barrier. The lower layer hugs the structure, while the upper layer defines the thermal mass surrounding it, with at least eight inches of dirt between the layers and sixteen inches on top. WOFATI designs emphasize a harmonious integration with the surrounding woodland, incorporating the "soil on wood" building technique. This method eliminates the need for a conventional concrete foundation, making construction faster and more affordable. A distinctive feature of WOFATI houses is the large gable roof on the downhill side, often incorporating glazing to allow light penetration, while at least 35% of the uphill wall features windows for optimal passive solar gain. This strategic placement and sizing of windows is crucial for maximizing natural light and regulating internal temperature, contributing to the effectiveness of Annualized Thermal Inertia.

The berm shed, a hallmark of permaculture design, is an eco-friendly, earth-sheltered structure renowned for its unique construction techniques. Earthworks are fundamental to its creation, as the surrounding landscape is carefully shaped to form the berm that will encase a portion of the shed's sloping roof. This berm serves a dual purpose, acting as both a natural insulator and a source of thermal mass, effectively regulating the internal temperature. The structural framework of the berm shed is often built using round wood timber framing, a technique that prioritizes using logs instead of conventional dimensional lumber, further enhancing its sustainable appeal. However, the longevity of these logs, especially when in contact with soil, is a crucial consideration. The sources recommend peeling the bark from posts before burying them, a technique born from experience and aimed at minimizing the risk of rot. Another technique for ensuring the durability of the structure involves incorporating gravel into the post holes. The gravel facilitates drainage, preventing water from pooling around the base of the posts and contributing to premature decay. These carefully considered details, combined with the innovative "attic" cell design at the termination ends of the shed, as described in source, showcase a commitment to sustainable building practices that go beyond mere functionality, exemplifying the core principles of permaculture.