Straw-bale Research Building at the University of Manitoba

Eco-building


  • Introduction


Straw-bale Research Building at U of M



Prepared by Om Joshi (2004) updated by Tom Pearce (2006)


Introduction

Straw has played a key role throughout the history of construction. The technique of straw-bale construction uses bales made from straw of wheat, oats, barley, rye, or rice in wall insulation which is often covered by stucco. (Dick, 2004) It is traditionally a waste product, which farmers do not till into the soil, but sell as animal bedding or landscape supply due to its durable nature. Farmers often burn off their remaining supply, which can cause air quality problems and greenhouse gas emissions. Straw-bale has recently become popular as an inexpensive, ecologically sound alternative to conventional construction methods.

The straw-bale research building is located on the University of Manitoba Fort Garry campus. The facility on campus is one of about 1,000 straw homes in Canada, each requiring about 300 to 500 bales to construct. (Dick 2004) The building can be a bit tricky to find as it is not marked on the standard campus maps. It is located on RH Way off Chancellor Matheson Boulevard near Innovation Drive. (please see the attached map for more details) Also you will need get approval to take a close at the building as there is a security sign that says ”only authorized personnel permitted”.

The building was constructed in January 2004 as a model for alternative building design. The project was pioneered by Dr. Kris Dick an engineering professor who teaches alternative housing design at the university. Dr. Kris Dick acted as a consultant on the project and stated that straw is an excellent and popular building material, citing qualities of high insulation values and fire resistance. The building is being used by the Faculty of Agricultural and Food Sciences where they are carrying out soil science experiments. (Dick 2004) The building itself is being researched by researchers with Biosystems Engineering at the University of Manitoba. Dr. Kris Dick is quoted as saying, as design engineers, we need hands-on experience with alternative building materials and data on which to base our designs. The research done on this building will provide valuable information for code forming bodies, building inspection departments, insurance companies and financial institutions.

Sample Straw-Bales Source: http://www.zekiahfarms.com

Straw-bale Research Building at the University of Manitoba Photo: T. Pearce 2006

The building itself is a one storey building with 4200 square feet. The value of the building is estimated at $280 000. The building was built with approximately 2,000 straw-bales covered with cement stucco. The straw-bales are supported by wooden beams. The inside dimensions of the structure are 40 feet wide by 107 feet long with an 18-foot ceiling height. The walls are 20 inches thick once covered by cement and stucco. The insulation value is approximately R50 which is two and half times that of a newer home. The fire residency is also significantly better than a conventional home. (Dick 2004) In terms of the specifics of the research it best described by Dr. Kris Dick here. Aside from the straw bale infill in the walls, what makes this structure really unique is that the posts, trusses and portions of the walls will be instrumented. This will provide information in real time about how the building responds to environmental loads from wind, snow, temperature and moisture. Another interesting feature is that the two long sides are oriented due south and north to study the effect of solar radiation on wall performance.  The photos show the 20 inch walls and notice also the wide eves which help protect the outside walls from moisture damage. Straw-bale homes generally have longer over hangs for added water protection.

This 'place study' considers the history the history of straw-bale construction and the sustainability aspects of straw-bale buildings. It focuses on the Straw-bale Research Building at the University of Manitoba and the various research opportunities provided by the building.

Sometimes there is a combination of different straw-bale building designs, however, there are two main types of straw-bale houses these include those which use straw-bale as in-fill (i.e. insulation) and those that use straw-bales as load bearing walls. There are pros and cons to both types. Straw-bale in-fill is generally more conventional and easier to get approved by conventional building codes and inspections.  This is as result of it using beams for the load bearing aspects. Using straw-bales as load bearing walls however requires a bit more planning and can be more labour intensive. Using straw-bales as load bearing walls likely has a smaller ecological footprint when compared to the more conventional straw-bale in-fill design, particularly where bales are within the same bio-region and travel less far than other materials. Furthermore, straw-bales homes can take the shape and appearance of any type of traditional home. Straw-bale buildings are generally limited to one or two stories in height.

Challenges: As discussed by Kris Dick, it can be more difficult to obtain building permits for such non-conventional buildings. Municipalities must develop guidelines for approving such unique buildings by streamlining the application process. Reworking current building codes and inspections will no doubt have to be part of the overall solution and approach to straw-bales buildings. Another challenge of straw-bale construction is the difficulty in getting insurance when there is limited experience with such structures in a region.

History:
Straw-bale construction was devised in the mid-1800s in the Sand Hills of Nebraska (www.dsaarch.com). During the late 1970s, Louis Gagnon used straw-bales construction technique to withstand the extreme cold of Canadian north. In this method, which came to be known as Quebec style, each bale is encased in concrete – inside and out, as well as the ends, top and bottom. This gives the structure, strength to support the weight of roof and imperviousness to water, rodents, and insects. However, this style turns out to be approximately as expensive as conventional wood frame house construction. Later on, David Cameron and Nancy Sherwood from Nova Scotia altered the Quebec style by using concrete columns, which formed the load-bearing members of the wall. Instead of using concrete horizontally, they used two lengths of rebar on top of two rows of bales. These rods were secured between columns for more rigidity. This style of construction technique is known as Nova Scotia-style

In western Canada, a straw-bale church built in 1950s stands as an evidence of the pioneers of this building archetype. Jorg and Helen Ostrowski have led the straw-bale initiative in the province of Alberta, which includes the first straw-bale commercial building in North America built in 2000.

This is the oldest known bale building still in existence in Nebraska. Source: http://www.strawhomes.com/

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