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By Dan Gunderson

Minnesota Public Radio

FARGO, N.D. (AP) 鈥� Two small houses are going up on the back half of a lot near a busy street, not far from downtown Fargo.

鈥淭hese homes are identical in blueprint,鈥� explained Grassroots Development President Justin Berg, the man behind this one-of-a-kind construction and research project. 鈥淭hey鈥檙e 13 by 23, with 12-foot ceilings 鈥� there鈥檚 a loft in each of them.鈥�

One of the houses is being built with a traditional wood frame and fiberglass insulation. Currently, it鈥檚 covered with a shiny, white wrap.

A second house a few feet away also has a wood frame. But the walls are filled with 12 inches of hempcrete, giving it a brown, textured look inside and out. The raw material is called hurd. It鈥檚 the inner woody core of the hemp plant, chipped into small pieces.

The hurd is mixed with a lime binder and water.

鈥淎nd you blend the mixture to a consistency, a nice sort of chicken salad 鈥� is our joke 鈥� consistency,鈥� Grassroots Development sustainability consultant Sydney Glup said. 鈥淎nd we hand-packed, physically hand-packed, this entire house.鈥�

They were guided through the process by Bismarck, N.D.-based Homeland Hempcrete, but the process was easy to learn, Glup said. It was a lot of work schlepping buckets of the material, dumping it into forms and packing it so the walls would be even after the forms were removed.

The hempcrete walls need to cure for six weeks before they are covered inside and out with a finish layer of plaster.

These homes might become short-term rentals, but the primary purpose is research.

鈥淲e鈥檙e just trying to get that concrete, non-biased research to contribute to the industry so we can troubleshoot and figure out how to do better,鈥� Glup said. 鈥淲e want it to be so that anybody who wants a healthier dwelling can afford it.鈥�

To collect data, sensors are tucked into the walls of both houses to monitor moisture and air temperature. Energy consumption will also be closely monitored.

鈥淭his, from my knowledge, is the only study of its kind,鈥� said Riley Gordon, principal engineer with the Minnesota-based Agricultural Utilization Research Institute, a partially state-funded nonprofit that helps develop new markets for Minnesota crops.

鈥淲e鈥檙e just looking to 鈥� leverage the opportunity of having these two buildings built side by side,鈥� Gordon said. 鈥淭hey鈥檙e identical; it鈥檚 perfect for a controlled study.鈥�

Gordon is working with Minneapolis-based Center for Energy and Environment, which will analyze the data collected from each home.

These hempcrete walls don鈥檛 provide structural support. Two-by-six wood studs give the wall strength.

Hemp is touted as a healthier alternative to insulation, reducing mold by creating walls that breathe, providing excellent insulating properties and serving as thermal mass, storing heat. The material is also flame resistant.

But there鈥檚 a need for data to validate some of those claims, Gordon said.

鈥淯p till now, a lot of the talk has just been a lot of claims that haven鈥檛 really been backed up by a whole lot of data,鈥� he said. 鈥淪o I think this is going to, for good or for worse, provide some answers to questions that I鈥檝e heard pretty often about this material. So I think it鈥檚 a very important study, and timely.鈥�

The cost of construction is about 25 percent higher for the hemp house. That鈥檚 partly because raw materials are still hard to find and expensive. But Berg believes this research will show hemp construction can save money long term.

鈥淧aying more up front and getting those savings over time by energy usage, you know, having a biodegradable structure,鈥� he said. 鈥淵ou start measuring out the materials and its impact and I think that鈥檚 where we鈥檙e hoping to help shine a light on it.鈥�

To purchase raw material that met their standards for consistency, the team had to buy the hurd in 400-pound bags from a company in Kansas and ship it to Fargo, Berg said.

There are at least two new hemp processors starting in Minnesota, and Berg is building in Wahpeton a processing facility that he plans to have operational later this year. But he expects it will take months to fine-tune the processing to turn out a high-quality product.

There鈥檚 still a steep learning curve, Berg said, from farmers who grow the crop to processors that turn out raw materials, but he鈥檚 willing to invest in the belief that hemp will become a sustainable construction alternative.

鈥淚t鈥檚 definitely the early days,鈥� he said, 鈥渁nd I think in 10 years, you鈥檒l see an industry that has a real impact.鈥�

The region will need more hemp processing capacity to bring raw material prices down, and farmers need to be convinced hemp is a viable alternative crop, Berg said. He would like to see the federal government do more to encourage hemp production in the battle against climate change.

鈥淵ou look at something that鈥檚 going to help sequester carbon in the soil with a deep taproot crop as well as being put into materials that are stored for 100-plus years and continue to sequester carbon,鈥� Berg said.

But ultimately, farmers will need a consistent market for the crop, and the construction industry will need to accept hemp as a viable alternative material. Berg hopes this research project, on a tiny plot of land in Fargo, will help convince more builders to try using hemp.