Left Hand Hemp knows there is a better way to build. Through hempcrete building workshops, they teach how to work with the renewable plant of hemp. Community members, students, hemp industry professionals and interested construction groups came together to help build an architecturally rendered, CO2 sequestering and fire-resistant building from “Hempcrete”.
Hempcrete consists of hemp hurd, lime and water. Here is what we did:
First, Architect Bob Escher with Escher Designs in Vermont and Homeowner Eric McKee came up with the design for the 16 x 20 workshop building.
Next, McKee talked to the city building code office about the properties and benefits of hempcrete and got an approval to build a 16 x 20 workshop space! A concrete base was laid and in three weeks, we would be ready to begin putting up the structure!
The General Contractor, Sawmill and Builder, Mark Cover from Forbes Road Sawmill put together the post and beam structure with wood from McKee’s family land in Pennsylvania. Beautiful 8 inch thick beams were milled and shipped to Denver. With the help of right hand man, Onefree Foster – the post and beam structure was up in just 2 and a half days!
Then the forming fun begins! We adjust the forms to the size you wish to have to the wall. and ceiling. There are some ares (such as the peak in the roof) that will need special size forms, just make sure it a consistent measurement. For this case, the forms were 8 inches wide on the walls and were made for 12 inches of hempcrete insulation on the roof. According to the book, an 8 inch wall could have an r-value of 5 per inch. By building in a monolithic way, we are able to close any thermal gaps.
Then, we MIX! The simple recipe of hemp hurd, lime and water is used in this hempcrete insulation material. In a mortar mixer (not concrete mixer) we mixed together Saint Asterie Hydraulic Lime, Ole Dominion Hemp Hurd and water.
We had teams mixing and packing in the forms. The mixing team tested each batch to ensure we reached our medium density goal. Once the batch was ready (about 5 minutes in mixer) we gave it to the packing team. When packing in the forms with the hempcrete mix, it is important to remember to firmly pack every corner and crevice.
We replaced fiberglass and other noxious insulation with hempcrete.
We replaced the need for drywall which eventually will off-gas by using hempcrete instead.
We replaced the need for toxic paint with an Earth-dye and natural plaster.