Rush Cottage - Earthbag Construction — SCOTT MCLEOD

Rush RESIDENCE -

an exploration in EARTHBAG CONSTRUCTION

The Rush Residence is an ambitious and unique project located in the serene, heavily wooded landscape of Southwest Washington State. This earthbag cottage was designed for a young couple who envisioned a home that not only provided a cozy and inviting atmosphere but also harmonized with the natural surroundings of their expansive property. With a deep appreciation for sustainable living and a desire to build something truly distinctive, they chose earthbag construction—a method that is both environmentally friendly and structurally resilient.
From the outset, the project presented several challenges, primarily due to the unconventional choice of building materials. Earthbag construction, while sustainable and cost-effective, is not a widely recognized method in traditional residential building. As their architect, I embarked on a comprehensive research journey to ensure that this alternative construction approach could not only function effectively as a home but also adhere to the rigorous standards required by local building codes. This involved a thorough analysis of structural integrity, energy efficiency, and compliance with the International Residential Code (IRC), particularly given the seismic and climatic conditions of the region.
Convincing the local building department of the viability of earthbag construction was a critical part of the process. Through detailed presentations and collaborative discussions, we successfully demonstrated that the earthbag home could meet or exceed all necessary safety and energy requirements. This persistence paid off when the project was approved for a building permit in May 2024, marking a significant milestone in the couple's journey toward realizing their dream home.
Construction of the Rush Residence began in the summer of 2024, setting the foundation for what will become a one-of-a-kind residence. The design, which spans a total of 2,572 square feet, includes various outdoor living spaces that enhance the connection between the home and its natural environment. The cottage-style aesthetic, combined with the robust and eco-friendly earthbag walls, will ensure that this home is not only visually appealing but also built to last. As the project progresses, it stands as a testament to the possibilities of alternative construction methods and the beauty of sustainable living.
ARCHITECT - DESIGN AND PERMITTING
May 2024: Building Permit Approved
Summer 2024: Construction Begins

COTTAGE PLANS AND ELEVATIONS

Colored plans and elevations, which were part of basic design package

interior imagERY

Interior perspectives of various locations within the cottage.

INTERIOR HALLWAY LOOKING TOWARD LIVING ROOM

STUDIO 1, ROOM FOR CRAFT, ART AND STORAGE

ALTERNATIVE CONSTRUCTION MATERIALS AND METHODS

One of the key elements of this project was to meticulously imbed building and energy code compliance into the detailing of structural earthbag wall, while still trying to achieve the functional characteristics found in a traditional wood frame.

The wall assembly was key component to the overall design goal. An expectation, where non-traditional building materials had to achieve the rustic charm of traditional cottage architecture with the strength and energy efficiency of modern construction. Below is a detailed breakdown of the wall assembly, highlighting the various components that make this wall both durable and environmentally friendly.

The structural wall of the Rush Residence is a meticulously engineered assembly designed for both durability and energy efficiency. The exterior begins with a thick stucco finish applied over steel mesh, creating a weather-resistant and aesthetically pleasing surface. Beneath the stucco, the core of the wall consists of a 14-inch thick reinforced sandbag wall, filled with a soil mix, and reinforced with galvanized wire mesh on both faces. This is further stabilized by vertical reinforcement and masonry joint reinforcement, including two strands of barbed wire between the courses.

For insulation, 10-inch tube sandbags filled with R-27 perlite are attached to the earthbag wall using barbed wire, providing an effective thermal barrier. The wall is capped with a 2x10 top plate, which supports the roof assembly consisting of a box beam and scissor truss design, insulated with R-38 closed-cell foam in the non-vented attic space. The floor assembly below the wall includes a compacted earthen base, a vapor barrier, and 12 inches of perlite insulation, topped with a finish layer that can include stone for added durability.

Electrical outlets are integrated into the wall by staking them into the earthbags, with wiring stapled to the inner wall and covered in plaster, ensuring a seamless interior finish. This comprehensive wall structure not only provides robust support but also ensures high energy efficiency, making it a model of sustainable design.

This detailed wall assembly not only contributes to the structural integrity of the Rush Residence but also ensures that the home meets modern energy efficiency standards while maintaining the desired aesthetic of a traditional cottage. The use of sustainable materials like perlite insulation and earthbags reflects the project’s commitment to eco-friendly construction methods, making it a standout example of innovative design in the Pacific Northwest.

AI DESIGN EXPLORATION

To further enhance the overall design of the project, significant lengths were taken to thoroughly explore various options for finishes, colors, and general design aesthetics that would best suit the cottage design. This careful consideration aimed to ensure that the project aligns harmoniously with the client’s vision of their home.