Hemp-Lime wall build

I’m replacing two walls in the upstairs floor of my house in Vermont, USA. The house was conventionally built in the 90s using sheet rock softwood framing and fiberglass insulation. The floors are pine. I would love to use hempcrete as a replacement. I’m wondering if anyone has experience retrofitting with this material ? They are interior non load bearing walls. I’m mainly curious about the wall thickness and also it looks like ideally there is a masonry plinth supporting from the floor which in my case it would just be pine with the frame underneath. Let me know thanks!

Hi Maggie,

If I understand your question, you want to replace two non-load bearing, second-story partition walls--presumably 2x4 stud with sheetrock on both sides and no insulation?--with hempcrete walls?  

As you explore this make sure to consider the proposed wall's weight.  The original 2x wall with sheetrock is probably much lighter and easily supported by the floor joists without sagging.  Hempcrete, while having more fire barrier, acoustic, thermal, and hygric (moisture control) benefits than typical 2x partition walls is also probably much heavier, even if installed at a similar 4" thickness.

Jim

Hi Maggie,

I am an architectural designer over in NH. As much as I love hempcrete, I don't recommend retrofits with it, especially over existing framing. As Jim said, you're likely going to run into problems with weight. Secondly you need to verify your existing fasteners, wires, plumbing are all protected from the corrosive properties of the lime. Honestly Hempcrete sorta smells as it's curing. You certainly wouldn't want to live in the house for the month it will take to dry. If you are going for that plastered wall look for these interior walls you can use your existing framing, and infill or apply over it with a hemp, coconut or wood fiber panel that you then plaster over. Much lighter weight, faster renovation, probably save you some money. You will want to use adjustable depth boxes for your switches and outlets on those walls to make sure everything comes out flush.