What is Straw Bale Building?
Straw bale building was first used by the settlers of the sandhills region of Nebraska, who arrived in an area devoid of the traditional building materials. By using the "blocks" of compressed straw they were producing in their fields as large building blocks, they were able to create shelters for themselves and their animals that were warm, durable and straightforward to construct.
In the 1980s this building method, long forgotten, was "rediscovered" by people searching for affordable and environmentally responsible building materials, and in short order hundreds of straw bale buildings were constructed in the American southwest. Spreading from its new home in Arizona and New Mexico, straw bale building became a world-wide movement by the early 1990s, with structures being built in quantity on every continent.
Starting with straw
Straw bale building has at its heart the humble bale of straw. Straw is the stalk portion of seed and grain crops (including wheat, oats, barely, rye, rice and hemp). Once the seed head has been harvested from the plant, the dead and dry stalks are cut and baled. While bale sizes can vary, the bales themselves share the qualities that makes them ideal for building: good thermal insulation properties, wide availability, low cost, annual renewability, convenient size for handling and sculptability.
Making a building with bales
By stacking straw bales like over-sized concrete blocks or bricks and then plastering (or parging) onto the straw on the inside and outside faces, a wall of exception strength, beauty and thermal insulation is created. In Ontario, over 100 straw bale buildings have been constructed since the mid-90s, including many homes and cottages as well as agricultural, industrial and commercial structures.
Lots of good reasons
The appeals of straw bale building are many and varied.
The energy-saving performance is high among these. Studies by the Canada Mortgage and Housing Corporation (PDF) have shown that bale homes typically use 25-40% less heating and cooling energy than their frame-walled equivalents. Warmer in winter and cooler in summer, without the high energy price tag and high CO2 emmissions!
Straw bales are a low environmental impact material. The RS Means Green Building: Project Planning and Cost Estimating guidebook gives straw bales an embodied energy rating of just 0.24 MJ/kg. This compares very favourably to other manufactured insulations like fibreglass (30.3) and expanded polystyrene (117)
Not only does straw keep you warm, it uses a fraction of the world's valuable resources and energy to do so! Straw is already produced in sufficient quantity to provide for all of North America's housing needs, so there is no need for new farmland or significant new practices.
Straw bale walls are easily understood. Many people wish to have a hand in building their own homes, for reasons of both cost and personal satisfaction. Straw bale building concepts are simple to understand and put into practice. Many hands-on workshops and volunteer opportunities exist to help owners and builders learn the basics, and a bale raising is a fun and satisfying event.
Straw bale walls are highly adaptable. Unlike other great "alternative" technologies, straw bale walls are simply intergrated into modern construction practices. While the buildings can be highly unique in design, the walls are easily adapted to all kinds of conventional foundation and roof building methods, and accept standard windows and doors. This makes it more straightforward to "go green".
Straw bale walls are beautiful. Because they are thick and sculptable, the walls lend themselves to the creation of unique and personal spaces. Rounded window openings, carved niches, wide window sills, built-in window seats and a finished look that can range from smooth, square and shiny to wildly curvy and textured, bale walls allow owners an inexpensive way to get creative with their space.
The cost is no higher than conventional construction. In fact, the materials themselves (straw and plaster) are very low-cost, so owner/builders can save up to 50% of their wall costs. But even built by professionals, you can expect to pay no more for bale walls than for standard wood framed walls, but you'll be getting more than twice the insulation value and great aesthetic potential. And savings in energy costs will stay with you for the life of the building.
Many other advantages, from terrific fire ratings (good enough to be used as a fire wall in an industrial building!) to excellent sound insulation to a positive impact on local farming economies all make bale building a choice that's hard to beat.