Straw-Slip Wall with Lime Plaster
This wall was built to support a pre-fab greenhouse for the Campus Center for Appropriate Technology on the Cal Poly Humboldt campus in Norther California. During my tenure as Co-Director of the facility I worked with my team to set the foundation and build the supporting wall while demonstrating the use of straw-slip insulation and lime plaster. Uniquely the “straw” used for this project was replaced with the invasive European beach grass that is constantly being removed by volunteers along the coast. Over 10 years later the wall has maintained its integrity and continued to support educational natural gardneing for countless students.
Complete Greenhouse before Colored Lime-wash
Students learning to set up a hydroponic system.
"Truth Window" provides an educational peak inside the wall and allows monitoring of the experimental material.
Straw slip insulation, also knows as light clay insulation, utilizes the natural shapes of straw to reduce heat transfer through a wall.
Straw is coated in clay before being packed into a wood-framed wall between two temporary forms. These forms hold the mixture in place until it dries. Once dry, what is left is a rigid form of insulation that can directly be plastered with either a cement, lime or clay plaster. This material is extremely cost efficient in terms of materials but takes longer to install than conventional insulation methods. However, the final result is a wonderfully textured and sturdy wall that will allow the building to breathe while also holding heat due to its relatively high degree of thermal mass.