People have been using straw one way and another for building purposes for thousands of years, but it wasn't until the late 1800's that they began making bales out of hay and straw. In the treeless sandhills of Nebraska around this time, some enterprising person decided that straw bales might make a good house. There was probably a lot of trial and error involved in the first few houses that went up, but eventually they got so good at building houses out of straw bales that some of these houses are still standing-over a hundred years later!
Straw is an agricultural byproduct, much of which is burned to get rid of it. In the United States alone over one hundred million tons is burned annually, which contributes drastically to air pollution. Our solar energy facts show us that using straw in a well thought out design is a low impact resource that benefits not only the homeowner but the environment as well.
There are basically two methods of straw bale construction; post and beam, where the straw is used for infill and the roof is supported by the post and beam structure, which can be made of wood, steel, or concrete. The other method of construction is load-bearing, where the roof is actually supported by the bale walls themselves. A top plate is laid on the bale walls and secured with strapping or metal rods that go all the way to the foundation. The roof is then fastened to the top plate.
Straw bale construction can be used almost anywhere in the U. S, as long as care is taken in wet climates to assure that the bale walls be kept dry. In areas where moisture is a problem special precautions such as: roof overhangs, good foundations, and starting the bale stacks up off the ground, are good ideas. Solar energy facts tell us there are a number of advantages to building with straw, some of which are: superior insulation, soundproofing, and a certain comfort from the combination of straw and plaster. The straw itself is cheap and plentiful in agricultural areas, and the bales are easy to build with, as they are stacked like bricks and then pinned together using rebar, wood, or bamboo stakes. For added strength chicken wire or welded lath is sewn to the bales and then the walls are earth plastered or stuccoed inside and out.
The cost of straw bale construction is comparable to stick and wood, depending on the amount of labor the builder can provide. A great deal of labor is involved in the plastering of the bales. The plastering on straw bale construction is very important. The breatheability of the walls is dependent on the proper mix and application of stucco or plaster. Some people choose not to use a netting on the outside of the straw, but to plaster directly to the straw itself. When using this option, the first coat applied is a thin clay slurry which is absorbed into the surface of the straw. Three more coats follow this to achieve a final thickness of from one to three inches. There are many different recipes one can use for the plaster, which include materials such as: earth, loam, sand, lime, and cement. Many of these recipes use mostly the earth found directly on the building site, combined with lime or cement.
Renting a stucco spraying rig would undoubtedly save a great deal of labor. Some people doing this work invite a bunch of friends and relatives and have a plastering party! It's important to have someone with experience or at least knowledge of the process. Workshops are offered in many parts of the country and would be a very valuable investment in time and money for any prospective builder.
Our solar energy facts show us that straw bale construction is an extremely important resource in many areas of the country. Habitat For Humanity has built straw bale houses. Mother Earth News has had several articles on building with straw. Here are some books on the process: Serious Straw Bale: A Home Construction Guide for All Climates(Real Goods Solar Living Book) by Paul Lacinski and Michel Bergeron, Building a Straw Bale House: The Red Feather Construction Handbook by Nathaniel Corum and Jane Goodall, More Straw Bale Building: A Complete Guide to Designing and Building with Straw(Mother Earth News Wiser Living Series).
Showing posts with label energy efficiency. Show all posts
Showing posts with label energy efficiency. Show all posts
Wednesday, August 26, 2009
Solar Energy Facts for Homebuilders
For a person who is interested in building an energy efficient home in these times of rising costs, including energy costs, the amount of information is daunting if not downright scary. We'll try to pare the information down to something manageable by looking at some of the ways we can build and keep our energy demands under control. Our solar energy facts give us a number of options:
-Conventional structure-stick and wood
-Earth bermed-using earth for a moderator
-Rammed earth
-Rammed earth blocks
-Adobe
-Straw
-Earthbag
An energy efficient conventional house can cost anywhere from around sixty thousand to more than two hundred thousand dollars, depending on how much energy you, yourself are willing to invest. One thing to bear in mind-how much skill do you have for this kind of project? To build a successful energy saving house of this sort would require super insulation, photovoltaic or wind power, and solar hot water, as well as some form of space heating.
A well designed earth bermed structure has only minimal needs for space heating. I've seen many options for this including wood stove, baseboard heating, and European tile stoves. Combined with solar hot water and either photovoltaic or wind energy, this is an excellent way to go, and is adaptable to any climate. I've seen costs for this type of construction from the seventy thousands to over two hundred thousand.
Rammed earth is a viable concept probably only if you are prepared to do a tremendous amount of physical labor, or you have laborers available. This method involves using forms between which dirt is compacted layer after layer until reaching the desired height. If you are really interested in this process, I recommend two books, Comfort in Any Climate, by Michael Reynolds-Solar Survival Press; and The Rammed Earth House, by David Easton-Real Goods Press.
One of my favorite choices is rammed earth blocks. This concept was developed several decades ago in Columbia with the invention of the
cinva block ram. This is a mechanical device with a long handle with which one can compress soil to about half its former volume. With the right mixture of soil, water, and about 3% Portland cement, we can make earthen blocks that are very tough, strong, and cheap-really excellent building materials. These blocks are a product that can be pretty much used anywhere in the world.
Adobe is another of our prime choices, according to our solar energy facts. Some people might think adobe construction might be limited to our southwest, but for a slightly higher cost adobe bricks can be stabilised using either 3 to 6% asphalt emulsion or 5 to 10% Portland cement. There is a strong customer demand for adobe. In New Mexico half of all new homes selling for more than $300,000. incorporate some form of earthen construction. Most are adobe, but some of them are using new earthen technology.
In the last few years, building with straw bales has become very popular as a means of keeping costs down and providing a great deal of insulation. There are many good designs to choose from and this is another method of construction that is usable anywhere in the country, as long as one can locate the straw at a good price. This method of construction either uses the structural integrity of the stacked bales, themselves, or a post and beam construction with the bales just used as walls and insulation. Either scheme requires that the bales be stuccoed inside and out. This type of housing can be very cost effective with the proper design.
One method of construction that has gained a certain popularity in recent years is called earthbag construction. Basically it consists of polyester bags, filled with soil and stacked according to the design. The bags are nearly always stacked in circular patterns so as to achieve a certain rigidity. Barbed wire is laid between the courses to give strength to the structure. Plaster is applied to the outside to provide waterproofing. Solar energy facts assure us that this is a legitimate form of construction and seriously to be considered.
These are some of the main options we have when considering building with energy efficiency in mind. Before any kind of choice is made, the prospective builder needs to consider climate and land considerations. Size is another thing to think about because the smaller a structure is, the less energy it will require. The proper preparation for a venture of this sort will certainly make the outcome more satisfying; so, the more research, the better.
-Conventional structure-stick and wood
-Earth bermed-using earth for a moderator
-Rammed earth
-Rammed earth blocks
-Adobe
-Straw
-Earthbag
An energy efficient conventional house can cost anywhere from around sixty thousand to more than two hundred thousand dollars, depending on how much energy you, yourself are willing to invest. One thing to bear in mind-how much skill do you have for this kind of project? To build a successful energy saving house of this sort would require super insulation, photovoltaic or wind power, and solar hot water, as well as some form of space heating.
A well designed earth bermed structure has only minimal needs for space heating. I've seen many options for this including wood stove, baseboard heating, and European tile stoves. Combined with solar hot water and either photovoltaic or wind energy, this is an excellent way to go, and is adaptable to any climate. I've seen costs for this type of construction from the seventy thousands to over two hundred thousand.
Rammed earth is a viable concept probably only if you are prepared to do a tremendous amount of physical labor, or you have laborers available. This method involves using forms between which dirt is compacted layer after layer until reaching the desired height. If you are really interested in this process, I recommend two books, Comfort in Any Climate, by Michael Reynolds-Solar Survival Press; and The Rammed Earth House, by David Easton-Real Goods Press.
One of my favorite choices is rammed earth blocks. This concept was developed several decades ago in Columbia with the invention of the
cinva block ram. This is a mechanical device with a long handle with which one can compress soil to about half its former volume. With the right mixture of soil, water, and about 3% Portland cement, we can make earthen blocks that are very tough, strong, and cheap-really excellent building materials. These blocks are a product that can be pretty much used anywhere in the world.
Adobe is another of our prime choices, according to our solar energy facts. Some people might think adobe construction might be limited to our southwest, but for a slightly higher cost adobe bricks can be stabilised using either 3 to 6% asphalt emulsion or 5 to 10% Portland cement. There is a strong customer demand for adobe. In New Mexico half of all new homes selling for more than $300,000. incorporate some form of earthen construction. Most are adobe, but some of them are using new earthen technology.
In the last few years, building with straw bales has become very popular as a means of keeping costs down and providing a great deal of insulation. There are many good designs to choose from and this is another method of construction that is usable anywhere in the country, as long as one can locate the straw at a good price. This method of construction either uses the structural integrity of the stacked bales, themselves, or a post and beam construction with the bales just used as walls and insulation. Either scheme requires that the bales be stuccoed inside and out. This type of housing can be very cost effective with the proper design.
One method of construction that has gained a certain popularity in recent years is called earthbag construction. Basically it consists of polyester bags, filled with soil and stacked according to the design. The bags are nearly always stacked in circular patterns so as to achieve a certain rigidity. Barbed wire is laid between the courses to give strength to the structure. Plaster is applied to the outside to provide waterproofing. Solar energy facts assure us that this is a legitimate form of construction and seriously to be considered.
These are some of the main options we have when considering building with energy efficiency in mind. Before any kind of choice is made, the prospective builder needs to consider climate and land considerations. Size is another thing to think about because the smaller a structure is, the less energy it will require. The proper preparation for a venture of this sort will certainly make the outcome more satisfying; so, the more research, the better.
Solar Energy Facts-Hot Water
Solar water heating is a good first step when considering going solar due to low cost and high efficiency. When we look at solar energy facts we find that hot water represents the second highest energy demand in U.S. households. On an average most water heaters use as much energy in a year as a medium-sized car. A typical solar water heating system reduces the need for gas or electric water heating by about two-thirds.
Our solar energy facts tell us systems that use direct heating of water using the sun's rays consist of two main parts: 1. a collector which heats the water, and 2. a storage tank. The main types of collectors are integral tank and flat-plate. The flat-plate collectors are the most widely used for domestic solar water heating. They have an operating range from well below 0 deg f to around 180 deg f, which is almost exactly what is required. Flat-plate collectors are rectangular shallow boxes typically four by eight feet with a strong frame and glazing fastened to the front. The frame has a solid back and an absorber plate just beneath the glazing. The absorber plate has riser tubes, usually half-inch copper pipes running vertically, spaced 3 to six inches apart, and welded into manifold pipes which are positioned horizontally top and bottom. Copper fins welded to the risers help with the efficiency of the absorber. Insulation provided beneath the absorber also contributes to the efficiency of the whole unit. Low iron tempered glass is preferred for the glazing.
There are a number of tank options available for the person desiring to invest in solar hot water. The type of tank needed depends on several factors-climate, size, and cost being among the most important. One of the simplest designs calls for a flat-plate collector using coolant or anti-freeze coupled with a regular hot water tank with an insertable heat exchanger installed. This is called a closed loop system. This arrangement also requires a pump for cycling the anti-freeze from the collector, through the heat exchanger, and back to the collector.
These systems can cost anywhere from around a thousand dollars for a small do-it-yourself project, to as much as six to fifteen thousand for a high end, northern climate deluxe product. Federal tax credits are available nationwide and state credits and grants are available in some states.
The solar energy facts assure us that a domestic solar water heater is a practical and cost effective way to generate hot water for a home. Today's solar thermal industry includes reliable, efficient products and trustworthy professionals who can install and maintain your equipment.
Energybuff
Our solar energy facts tell us systems that use direct heating of water using the sun's rays consist of two main parts: 1. a collector which heats the water, and 2. a storage tank. The main types of collectors are integral tank and flat-plate. The flat-plate collectors are the most widely used for domestic solar water heating. They have an operating range from well below 0 deg f to around 180 deg f, which is almost exactly what is required. Flat-plate collectors are rectangular shallow boxes typically four by eight feet with a strong frame and glazing fastened to the front. The frame has a solid back and an absorber plate just beneath the glazing. The absorber plate has riser tubes, usually half-inch copper pipes running vertically, spaced 3 to six inches apart, and welded into manifold pipes which are positioned horizontally top and bottom. Copper fins welded to the risers help with the efficiency of the absorber. Insulation provided beneath the absorber also contributes to the efficiency of the whole unit. Low iron tempered glass is preferred for the glazing.
There are a number of tank options available for the person desiring to invest in solar hot water. The type of tank needed depends on several factors-climate, size, and cost being among the most important. One of the simplest designs calls for a flat-plate collector using coolant or anti-freeze coupled with a regular hot water tank with an insertable heat exchanger installed. This is called a closed loop system. This arrangement also requires a pump for cycling the anti-freeze from the collector, through the heat exchanger, and back to the collector.
These systems can cost anywhere from around a thousand dollars for a small do-it-yourself project, to as much as six to fifteen thousand for a high end, northern climate deluxe product. Federal tax credits are available nationwide and state credits and grants are available in some states.
The solar energy facts assure us that a domestic solar water heater is a practical and cost effective way to generate hot water for a home. Today's solar thermal industry includes reliable, efficient products and trustworthy professionals who can install and maintain your equipment.
Energybuff
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