Slip and Chip is another form of natural insulation that incorporates a mixture of wood chips coated with clay slip to bind them together. This infill system compares to light straw clay, but is faster and requires less drying time. The chips are roughly 2” in diameter and can be either dry or green. Our ratio of woodchips to clay was 3 to 1. Although a barrel mixer can be used, we mixed using tarps, tossing until all the woodchips were evenly coated.
This project was a bathroom retrofit at Aprovecho. To prepare the wall for insulation, we exposed the studs, and built out another frame, so that the thickness of the wall was 12” in total The two frames were connected together by attaching pieces of wood (3 per stud vertically). Once the wall is constructed, lathe was attached on the outside to create a cavity. Using a nail gun, we spaced them about an 1.5“ apart, so that there was just enough space that the woodchips wouldn’t fall out, but only attached it in increments. Next, we poured in the mixture until it reached the top part of the lathe. Then, we attached more lathe and repeated until the wall was complete. Before considering plaster or closing off the wall, wait until the wood chips are completely dry.