A house built from straw? Sounds like something the Big Bad Wolf would huff and puff over, doesn't it? But straw bale construction has a 200-year history in the United States, and it's more fashionable than ever as people seek to build eco-friendly homes out of renewable materials.
There are two types of straw bale construction: load-bearing and post-and-beam.
Load Bearing
This is when the straw itself carries the roof load. This completely eliminates the need for wood, but it's not a system that is used often today. The lack of strong structural support limits the number and width of window and door openings. Since most eco-friendly homes are being built to incorporate passive solar strategies (which require large expanses of glass), load-bearing straw bale construction isn't ideal.
Post-and-beam Structure with Straw as an Infill Material
This method is far more common. The straw is not relied upon for structural purposes, rather it is packed into a post-and-beam frame. The straw acts as a thermal skin, which provides insulation values ranging from R-25 to R-50. Post-and-beam structure straw bale can work in most climates and has been built everywhere from Alaska to the desert Southwest to the East Coast.
When you build a straw bale house, you finish it with natural plasters (no, you don't have walls with straw sticking out all over the place) that make it look fairly normal, though some say "straw bale walls create a comforting, soft enclosure of space that is more organic in nature than formed systems."