By Leona Krahn
The Alternative VillageBuildings Environmental
Buildings formed with unconventional materials like straw bales and hemp are being monitored at a unique research site at the University of Manitoba.
From the May 2015 print issue, page 34
The Alternative Village at the University of Manitoba in Winnipeg is a unique research hub situated on one-and-a-half acres. A venue for research, testing and industry partnerships, the Village also provides students with the ultimate in hands-on experience.
The Village got its start when a strawbale building was built during the winter of 2003-2004 to house research equipment while the university’s Faculty of Engineering building was being remodeled.
“I was given the great opportunity to construct a building using non-conventional materials for our engineering equipment during the building renovation, with the idea it could evolve into more of a permanent research centre. I jumped at the chance,” says Dr. Kris Dick, Ph.D., P.Eng.. Dick is an associate professor with the Faculty of Engineering Department of Biosystems, and the founder and director of the Alternative Village.
“There was a parcel of land on campus available, previously a storage ground for the physical plant. We now use the space to evaluate everything from the energy efficiency of new building products like straw, flax, oats, barley and hemp, to the effectiveness and durability of building systems.”
“My ultimate goal is to create a true multi-disciplinary centre where engineering students work in collaboration with students and researchers from other faculties, including architecture, environment and agriculture. This way, students are prepared for the real world of engineering where professions work together in design teams. The Village also allows students to get engaged with the [building] industry, which is equally important.”
“As design engineers, we need hands-on experience with alternative building materials and data on which to base our designs. The research done at the Alternative Village provides valuable information for code forming bodies, building inspection departments, insurance companies and financial institutions,” says Dick. ”The Alternative Village scenario allows us to test and research both nonconventional and conventional building techniques and materials.”
Strawbale research building
At the heart of the village stands the Biosystems Strawbale Research Facility, located in the original 4,200 sq.ft. strawbale structure built in 2004.
“Straw is an excellent and popular building material due to its high insulation values and, when covered with a plaster finish, its fire resistance,” says Dick.
Strawbale construction uses bales of straw of wheat, oats or barley covered in plaster. Straw is typically considered a waste product by farmers, who often burn off what they can’t sell for animal bedding or landscaping. The burning creates air quality problems and greenhouse gas emissions.
This particular building is a one-storey structure built with 2,000 straw bales covered with cement-based plaster on both the interior and exterior. The straw bales are interspersed with nail laminated posts that support the roof. The inside dimensions are 40 ft. x 107 ft. with an 18-ft. ceiling height.
The walls are 20″ thick and have an insulation value of approximately R40, which is at least twice that of typical batt-insulated wood frame house wall systems.The fire residence is also better than a conventional home, says Dick.
To allow the students to monitor in real time how the building responds to environmental loads from wind, snow, temperature and moisture, the building’s posts, trusses and portions of the walls have been fitted with measuring instruments.
Valued around $280,000, the building is also oriented with its length facing due north-south to study the effects of solar radiation on the wall performance. It has wide roof eaves to help protect the outside walls from moisture damage.
Test structures with fibreglass, cellulose, SIP, concrete-filled PVC and hempcrete walls
There are six smaller structures on the site, which are test buildings for evaluating the performance of different building envelopes. Heat transfer and moisture behaviour are studied.
The six buildings are all 16 x 16 ft. with identical roof and floor systems; only the walls vary.
The roofs consist of metal-plate connected trusses covered with corrugated metal sheeting. The ceilings are finished with 1/2″ gypsum wall board with 6 mil vapour barrier and R40 of blown in cellulose insulation. Floors are EPS foam structural insulated panels.
One test structure is wood frame with fibreglass insulation in the walls, and another is wood frame with cellulose insulation. Both have a 1/2″ gypsum wall board interior finish and painted 7/16″ oriented strand board (OSB) on the exterior.
A third structure has walls of 4-1/2″-thick structural insulated panels (SIP). The panels have 7/16″ OSB skins with 2-1b. polyurethane foam.
Fourth and fifth are buildings with walls of concrete-filled PVC. One has 4″ of concrete with 4″ of external EPS foam. The other has 8″ of concrete with the same 4″ of external insulation.
The sixth test building has hempcrete panels made from hemp hurd and a cementitious binder. The walls are 12″ thick. The exterior is covered with a building wrap, rain-screen gap and wood sheathing. The interior was left unfinished to investigate the effect of an air barrier on the ability of hempcrete to manage moisture.
“Hempcrete is turning out to be a great building material,” says Dick. “Hempcrete panels perform very well, comparable to the efficiency of fibreglass,” he says.
Earth building materials stabilized with artificial pozzulans are also being investigated. Dick says these alternative building panels (straw and hemp hybrids) could be the way of the future. However, the supply of hemp hurd is limited at this time.
Each test building is equipped with electricity and data lines that are tied back into the main strawbale building. Thermocouples, relative humidity sensors and power meters are installed in each structure. They are all heated with electrical resistance heaters to allow their power consumption to be measured.
In addition to monitoring the test buildings themselves, general research on wood building systems is conducted inside the main strawbale research building. This work includes full-scale testing of structural insulated panels systems, laminated dimensional lumber posts, and metal plate connected wood trusses.
There is also a greenhouse on site, which incorporates a mass wall to capture solar energy.
The greenhouse’s basic structure is made from steel tubing that is bolted together. The entire 22′ x 50′ building fits inside a 4′ x 4′ x 10′ box that allows for shipping.
The mass wall is located on the north back wall. Currently the wall’s interior layer is 6″ fabric-formed rammed earth that absorbs heat from incoming solar radiation. Behind this is an 18″ thick layer of wheat straw for insulation. Corrugated metal covers the exterior (see diagram).
The heat stored in the back wall is released into the growing space to reduce the supplemental heat requirements. The performance of the greenhouse is being evaluated and a computer model for designers is being developed.
Recent funding will see the addition of a gasifier that uses biomass as a fuel source and will be used to provide heat and electricity to the greenhouse.
This project is part of research on food security for northern Manitoba and the use of local materials for construction. The solar wall of the greenhouse will be reconfigured to evaluate the use of such things as stabilized soil, recycled plastic, biomass based insulation materials and repurposed landfill materials.
Alternative energy strategies are also being used. For example in the strawbale building solar air is being distributed with fans through a conventional metal duct system. Flat-panel solar water heat systems and several sets of evacuated tube solar water heating panels are also being researched. Alternative electricity generation demonstrations are also central to the Alternative Village mandate. A grid-tied, vertical axis wind turbine is one example.
Growth and Outreach
Alternative building techniques do present complications, says Dick, citing the difficulties of obtaining building permits and of getting insurance. Working with industry-funded research can also present challenges. After almost a decade of research the Village has provided insight into the use different materials. While some of the results have been published, a portion remains proprietary to industry partners.
But outreach and education are happening. The Village has established a connection in rural Honduras to work on projects that focus on sustainable living. Students from engineering, architecture and nursing work closely with the partner community after researching and prototyping design solutions in the Village.
And on August 10-13 the Village is hosting the Non Conventional Materials 2015 (NOCMAT2015) conference. It is the first time the conference will be held in North America.
“My desire, says Dick, “is to keep moving the Village forward, to grow the Village. I envision a facility where students, researchers and industry can work together. It also provides the general public with an opportunity to come and “scratch and sniff” various materials. They can meet with researchers and industry partners to gain insight into products that may be of interest to them. Aside from the usual challenges of funding, the Alternative Village will hopefully be providing interesting opportunities for our students and researchers for years to come.” cce
Leona Krahn is a freelance writer based in Winnipeg.