Updated: May 16, 2020
Hempitecture and Americhanvre spray apply 1,100 cubic ft of hempcrete in 5 days.
Ereasy Spray Applied Hempcrete Building, Warrenton, MO - May 2020
As construction is reopening and deemed essential across the US, construction projects are beginning to resume. Hempitecture had been consulting with a client in Missouri to complete a spray applied hempcrete project before spring. Due to coronavirus, this project was delayed until construction was permitted and all safety precautions could be put in place. In a rural location, this project was the perfect opportunity to complete the first hempcrete build of 2020.
The homeowner client, also a builder, self built the entire project with the help of local contractors, readying it for a hempcrete spray installation. This involved considering the mass of hempcrete, in this case, on average 10 inches, and framing accordingly. The interior walls are clad with interior finish magnesium oxide boards; a vapor permeable wall cladding that is fireproof and not susceptible to mold. When secured to the studs on the interior side of the house, hempcrete can be spray applied directly to the boards, encasing the studs and creating an envelope without thermal bridging.
The backside of the house presents a clearstory basement, spanning 24' from foundation to top of hempcrete wall. This presented a few challenges that scaffolding and good teamwork with Americhanvre made possible. Despite significant rain that made the job site muddy, as well as working through the learning curve of production installation on this size building, the team managed to complete the project in 5 days. Some of the equipment used to complete this included Hempitecture's skidsteer bucket mixer system, the Ereasy spray applied hempcrete system, a 375 CFM air compressor, and lots of hard work!
Spray applied hempcrete requires a substructure to be sprayed around. The client installed a geotextile mesh that worked very well for spray applying hempcrete, but it did rely on some specific techniques to install successfully. The Ereasy hempcrete system, invented in France by Damien Baumer, has only been used on projects twice in the US; both times by Hempitecture. As more people look to spray apply hempcrete, Hempitecture is happy to explain the challenges, limitations, and opportunities of using this system. Hempitecture is a distributor of the Ereasy system and Americhanvre is one of the first owners of an Ereasy system in the US. While it may not be for everyone, spray applying hempcrete can yield productive projects.
The client, seeking the healthiest home possible, opted for HempWool insulation for the ceilings. This project used about 10 pallets of Hempitecture HempWool insulation. The interior magnesium oxide board walls will be rendered with Limestrong plaster, with the outside hempcrete being rendered in Limestrong Build Plaster; a heartier, more rustic version of Limestrong Artisan. Special thanks to the client who did a great job executing the details to make the project hempcrete ready, Cam McIntosh from Americhanvre for joining us, and Bryson Peter who worked on his first hempcrete project ever with us.
For more information on hempcrete and HempWool materials and installation, reach out to firstname.lastname@example.org.