Straw bale building is a form of construction in which the primary construction material is straw bales. There are a number of different styles and approaches to this type of construction which are practiced in several regions of the world. While straw bale construction has ancient roots, people in the modern world are primarily interested in this form of construction as an environmentally friendly alternative to traditional building techniques.
In load bearing straw bale buildings, the straw bales are designed to bear the weight of the building. Classically, they are reinforced with rebar which is set into a foundation. This type of construction is not permitted in all areas, due to concerns about its integrity, although load bearing straw bale structures do seem to hold up very well over time. As an alternative, some people use a non-load bearing technique, in which the support from the structure is provided by posts and beams, with the straw bales filling in the walls.
A number of types of straw can be used, as long as they are dry and tightly baled. Once all of the bales are in place, the structure can be covered in mud, adobe, and other plastering materials, sealing the straw bales in. Some breathability is strongly encouraged, so that the straw bales cannot mold and rot. Plumbing and electrical cabling can be run under floors, or designed to be built into the walls, depending on taste and prevailing building codes, and roofing materials can include sheet metal, thatch, and tile.
This type of building is often touted as an environmentally friendly building technique. Straw is an excellent insulator, which can cut down on energy bills substantially, and it is also a fully renewable building material. When the plaster is made from materials found on the land, and recycled or reclaimed materials are used as windows, doors, roofing, flooring, and so forth, the building's impact on the environment can be greatly minimized.
Straw bale construction is especially well suited to warm climates like those found in the desert. The thick walls will keep the interior of the structure cool during the day, and conserve heat during chilly nights, keeping the temperature relatively stable. The dry, hot climate will also prevent damage to the walls of the building. In wet, humid climates, a straw bale building requires much more maintenance, and it may not be feasible at all in some regions of the world.
People who are interested in straw bale building can take workshops where they will get a chance to participate in the construction of straw bale structures, and they can also offer to host a workshop on their own land.