Dear All, I have in interesting information. I have spoken to a guy who does natural plastering for over 20 years and he said that the houses in Austria which he worked on 20 years ago show problems now. The plaster which was applied directly to the strawbales on the outside is cracking and falling off and they found out because over the years some moisture got inside the straw and made it crumble and dissolve. So the house is no good now and there is no easy way to repair it. I wouldn`t like my house to live the same misfortune in cca 20 years time. This is why vapour barrier and wind proof facade is a good solution. I can`t wait to hear your comments.
There is a common approach to making building decisions that yields problems. It begins with the uninvestigated anecdote, such as, "I talked to a guy who said...", or "I saw a house that had problems because...". The information may have some bits of truth in it, or it may be totally erroneous. For example, I don't know if there were any strawbale houses built in Austria twenty years ago. Certainly not many. Then we generalize the questionable information into one or more general principles. Ignoring, among other things, the fact that the first houses built with any experimental method or material are usually built by amateurs, and illegally. And that we learn things with practice. The problems of the prototypes tend to get solved with more experience.
Next, we add more unsupported information- that "there is no easy way to repair it." On the contrary, there is no plaster easier to repair than earthen plaster. Lime plaster is pretty easy to repair, too. The most widely used plasters, based on Portland cement, are among the hardest to repair. However, they are used successfully in many cases.
Most problems with the bales themselves are fairly easy to repair. Removing and replacing one or more damaged bales has been done on multiple occasions, and the process has been photographed, written up, and published in places like The Last Straw Journal. The process gets harder, when the builder has decided to "improve" standard strawbale construction via something like drilling holes through the bales, and filling them with concrete, to "strengthen" the structure. If there is large-scale failure of the bales in a given house, then this reflects a significant design or construction problem, which could not have been solved by plaster choices.
The final unfortunate step of this kind of thinking is often the adoption of a new, untested approach, based on imagination and supposition, which is conceived as a breakthrough solution. [Such ideas may not be truly new. They may have already been tried, with negative results, and therefore, are seldom seen. But they seem new and clever to the builder.] Such ideas generally have unintended consequences. Often, the thought is, "I will keep all the moisture out." What this usually leads to is keeping excessive levels of moisture in. An example repeated all over the world is the plastering of earthen buildings with Portland cement plasters. Earthen buildings, which survived centuries with properly maintained earthen plasters, are covered with cement stucco "to protect them", and within a decade or two, have major failures due to trapped moisture. Similarly, in wooden structures, improperly designed or constructed vapour barriers have caused major moisture, mold, and structural problems in millions of houses around the world.
We can't build with perfection. The International Space Station leaks. There has never been a structure built with more engineering skill, more care, higher cost per square meter, or higher stakes for failure. It is built the very best that we know how. It suffers no wind storms, no buffeting rain, no earthquakes, and no loads, since the gravity stresses are all equalized in a free-fall environment. Yet it leaks.
Let us not imagine that we can build a house that solves problems that humans have never solved before. Rather, I suggest drawing from the best ideas and most reliable solutions that have been proven in actual construction and in rigorous testing. Most of want to build great structures, and improve on what has been done before. I think that is possible, and laudable. I think we can improve building practices and methods by understanding what has been tried, and investigating new possibilities that add on to, combine, or extend previous successes. Or, more interesting to many of us, we can explore techniques which simplify processes and minimize the excesses of conventional building. Working more harmoniously with nature, rather than fighting her. Making maintenance and repair easier, rather than imagining that we can avoid it. New ideas and approaches are most likely to succeed, when the mesh with the general principles of building science.
Attempting to innovate without careful study of previous successes and failures is perilous. There are many failures among experimental buildings. In part, because they are experiments. In part, because the builders often do not study what has been tried before, and don't test their innovations before applying them to a house. At the risk of repeating myself, there are good resources and references available in books and on the web, including: The Last Straw Journal <http://thelaststraw.org/>, the Ecological Building Network <http://www.ecobuildnetwork.org/>, Building Science <http://www.buildingscience.com/>, Bill and Athena Steen's The Canelo Project <http://www.caneloproject.com/>, and Andrew Morrison's <http://www.strawbale.com/>
Derelict Derek Roff Language Learning Center Ortega Hall 129, MSC03-2100 University of New Mexico Albuquerque, NM 87131-0001 505/277-7368, fax 505/277-3885 Internet: derek@unm...