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Tag: practical
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Building an Energy Efficient Straw Bale Home: Design criteria for Inglewood straw bale
This article first appeared in The Owner Builder 196 August/September 2016. www.theownerbuilder.com.au
By Brian Hodge
As we embark on our 20th owner-built home, I reflect back over the progress since purchasing property last year.
We were surprised the property didn’t have power, sewer, or water but discovered it actually had sewer connection just over the back fence. We were somewhat pleased when we received the quote for electricity connection of $5,050. Mind you, that did not include the connection of the power to our meter box.
Having mentioned the meter box, I am flooded with the memory of its incorrect positioning in my unavoidable absence and the challenges that we were faced with as a consequence (see TOB 195 June/July 2016). But who can complain. The end result was that we have revisited the design and now have a better one that is more interesting. And who can forget the bonus sewer connection at the back of the block, which will save us around $10,000 that we would have spent for a septic system.
A place to run courses
When we first went looking for land our primary motivation was to get a low cost piece of land on which we could run the practical part of our owner-builder straw bale building workshops. This was a precursor to being willing to sell the straw bale house in Ladys Pass. To be a straw bale building consultant with nowhere to do courses and nothing to show people was not an option and the solution had to make financial sense.
Consequently, I did an internet search for ‘land under $50,000 Victoria.’ The result was land in Loch Sport, which was too small and, from previous experience, has too many mosquitoes, and land in Inglewood, Victoria. Inglewood is in central Victoria about 35 minutes north of Bendigo with a population of a bit over 1,000. It was established in 1859 and is still a great place to find gold. It has a good supermarket, hospital, permanent doctor, pharmacy and most important, a couple of good old fashioned pubs for great meals. It is also the town where my youngest son, his wife and two of my grandchildren are located. However, the criteria were primarily price and size.
There was an 8000m2 block for around $45,000 near a light industrial area, a 2000m2 for $70,000 or a 1000m2 for $35,000. We put in an offer of $33,000 on the last block, which was accepted.
Position, position…
The only issue, which was a big one, was its orientation. It is only 20 metres wide and faces north-west. In order to control heat input and get some passive solar benefit in the design, we had to design a house that is twisted on the property. This option consumes a lot of land, which was complicated by our need for wide eaves for a straw bale house. Regulations stipulate that living area windows must have a minimum of 1000mm of clear sky from the boundary, which meant that we had to be set in from the side boundary a minimum of 1900mm to allow for the 900mm eaves. We also needed truck access to the backyard to take deliveries of bales etc. for workshops, further restricting our build space.
We finally settled on the concept of building a U shaped house with a central courtyard as this would enable us to get passive solar benefit in the master bedroom and living area. Not a huge amount, but enough to make a difference. It also provided us with a outdoor private area, which is important to us as we have lived on country properties for the past 12 years.
Energy rating
I had our energy assessors check to see what difference this adjusted orientation would make on stage one of the construction, as opposed to building parallel to the front boundary. We were surprised that the energy rating actually went up from 5.4 stars to 6.3 stars even though there is only one window that faces north.
As we are building in central Victoria, the energy rating is primarily directed toward the energy required for winter heating. However, we get some really nasty weather in summer with temperatures reaching high 30s and even mid 40s. Consequently the design criteria also included resistance to summer heat. The central courtyard faces due west, however it has a deep verandah to protect smallish windows from the afternoon heat from the west, and the windows facing east are limited.
One of the big concerns for restricting heat input in summer is to avoid doors that open directly into the house from the north, as it is the north wind that brings high temperatures to the area. I have therefore included a good size entry on the northern end of the house with the external door facing east, which will dramatically reduce the impact of those hot northerly winds.
Airflow manipulation
The cooler summer breezes often come from the south-east, so we have included casement windows on the south-eastern boundary to funnel those cool breezes through the house. The benefit of correctly hinged casement windows is that they tend to trap the breeze and funnel it into the house rather than simply working with straight airflow. When you are trying to get cool air into your home it is best to open the windward windows fully but close the windows on the opposite side of the house to 50%, as this creates a vacuum resulting in greater airflow.
As this is a residential block I expect that airflow will be a bit of a challenge as we have boundary fences which will restrict it. I have also incorporated a flat ceiling in part of the house in order to accommodate ducting for an air circulation pump to force the early morning cool air through the house if the temperature in the house is higher than the temperature outside. Our previous straw bale house in Ladys Pass had the same issue, which was overcome using an evaporative cooler as an air circulation pump. The cooling function of the unit was hardly ever used, and would not have been missed, so I am planning on simply fitting an air pump this time.
The master bedroom window faces north onto the central courtyard, however the window is not within the shadow of the verandah roof so we will get good passive solar benefit in winter. It also means that we have a private outlook, and with Molly, our big guard dog, we are assured of security! (Molly is a miniature Maltese Shiatsu)
As this is house number 20 for us personally, it was difficult to find something a bit different to do, so we eventually settled on a curved roof with a curved ceiling. This will be achieved by building box trusses on site. It is a very cost effective method of roof construction and I am looking forward to trying it out, as I have never done it before.
With all the design, engineering and building permit issues behind us it is now time to get to work and build it. I am going to take my time and enjoy the process as I suspect this will be the last home that I build, although many people scoff at this idea, thinking that I am either crazy for building so many or that I am addicted to the process. Personally I am not sure, but I am going to enjoy this project as if it is my last.
Brian Hodge is the director of Anvill Straw Bale Building Consultants. He has nearly 40 years experience in the building trade, and now consults predominantly on straw bale construction. Brian is the author of ‘Building your straw bale home’ and will be blogging about his build. Anvill Straw Bale Building Consultants: Whether you are building a mansion or to a strict budget, we are here to help. www.straw-bale-houses.com
On – 23 Apr, 2017 By Cherie Peacock
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Straw Bale Construction: A Sustainable and Renewable Building Material
In this modern day we primarily construct buildings with materials that retain a single life use, meaning at the end of its course the material remains unusable and/or un-recycled. Examples of said materials are concrete, various metals and asphalt. If you look back far enough before the industrial revolution, you would find houses with walls built out from straw bales. Though straw today is used as a biofuel, animal feed and confectioning various objects, it can also be used as a very ecological and effective construction material.
While straw has been used to create housing in Africa since the Paleolithic Era, it’s seeing a modern renaissance with the rise in popularity of straw bale construction. This affordable and sustainable means of building is being discovered by modern builders and homeowners across the globe, with some standout landmarks assisting its rise to prominence.
But what exactly is straw bale construction and do the advantages outweigh the disadvantages of this age-old building method?
History of straw bale construction
The history of straw bail construction has a strong foundation in the 1700’s, but dates much further back in Africa during the Paleolithic era (Old Stone Age). Germany and France in the 1700’s used straw as a means of constructing various buildings that can even still be visited today. A century ago in Nebraska, the rapid evolution of farming equipment pushed the use of straw construction for building houses, churches and even museums. Today there are a modest amount of architects that specialize in straw bale construction homes, pushing the boundaries of what can be accomplished with the material. Notably, a Swiss architect named Werner Schmidt has been capable of building modern multi-story houses over 2700sq.ft (250sq.m).Straw bale construction is a relatively sustainable construction method, with straw being a renewable material that is readily available. After the edible part of grains have been harvested, their stalks are disposed of by farmers and in many areas, they are burned. Transforming them into straw bales gives them a new life and reduces the air pollution which results from burning.
Straw bales also have high insulation qualities, keeping the building warm in winter and cool in summer, with R-values between 40 and 60 when built correctly. It is also relatively cheap, made from an agricultural by-product. But it’s important to keep in mind that the cost of straw bales differs depending on when they are harvested and how far they need to be transported. If they need to be stored for lengthy periods or transported long distances, then the costs escalate accordingly.
Another advantage of straw bale construction is that it is a relatively easy method for novice builders, meaning that it can be utilized by owner-builders without extensive experience or volunteer crews. This also reduces the labor costs involved in building which can be substantial in many parts of the developed world.
Straw bales take little energy to manufacture, with the bailing process and transportation the only additional energy required (other than the sun used to grow the plants). When compared to other insulating material such as fiberglass, the energy-intensity to produce the material is significantly reduced. They are also 100% biodegradable and can easily be plowed back into the earth if they are no longer needed.
Straw bales construction also has some favorable aesthetic qualities, creating thick walls which allow for window seats and shelves, as well as lending itself to numerous architectural styles.
How to build with straw
The methods of building a straw house is very different to that of our own. From the bottom up, a foundation the width of a bale must be poured in place to support the straw walls. When straw is baled, you obtain rectangles of varied dimensions between 36”x18”x14” (915x455x355mm) to 48”x24”x16” (1220x610x410mm). These rectangles are stacked like lego blocks up to the desired height, and wood rods are inserted at each 5 to 6 layers of straw in order to anchor each bale together. Because straw is an organic material containing air, the exterior and interior finishes must also be composed of 100% organic materials to allow the walls to perspire. This said material is typically a concoction of clay, sand and straw. By adding water to all these materials, you create a mud-like mix that is easily manipulatable and smooth when dry. The roof itself can be a typical roof truss construction; because of the the structural integrity and high stability of the straw walls, the roof can simply rest on and be anchored to the walls.Advantages of building with straw
There are many advantages to building with straw: the low environmental impact of the materials are obviously a major assets, but studies also show the energy efficiency of the straw bales exceeds that of modern construction. Because its high thermal of R1.5/Inch (25mm), it effectively retains the interior temperatures in even the coldest of climates. Another major benefit is that straw and clay are abundant materials, making them readily available at low costs. Because the construction process with these materials is quite primitive, there is little need for modern construction tools therefore making it easily done by almost anyone. Though straw might be a highly combustible material on its own, a study has shown a straw wall with clay finishing on both sides retains a fire separation of 90 minutes, which greatly exceeds that of typical residential construction. Finally, at the end of the building’s life, the materials can be fully recycled back into the environment with little to no impact.Disadvantages of straw buildings
Similar to many other building materials, straw bales can be susceptible to rot if they are not kept dry, which is one of their biggest problems. You need to ensure that moisture cannot enter the bales from the roof and in areas of high humidity or rainfall, this may not be practical. If they are exposed to water, compressed straw bales may expand as they absorb the moisture, resulting in further cracking and greater infiltration of water as a result.
If mold becomes an issue, it may release toxic spores into the wall cavity and surrounding air, and the internal temperatures can rise as the straw bales decompose. Rats and mice can also be a problem during construction as they like to burrow in the bales, and care should be taken to ensure they are evicted before sealing.
Building with straw bales can also be challenging when it comes to obtaining building permits or insurance coverage, as they are not a conventional building material or part of all local building codes. You may have to be more persistent in having your plans approved, but local architects or engineers with experience in using natural materials may be able to assist in this.
Because of the thickness of straw bale walls, you should also keep in mind that more of your building area is being taken up with wall space and you should design your plans accordingly.
Justin Langlois is a former Build Abroad volunteer who found his passion through his travels. As a Canadian Architectural Technologist, he plans on becoming an architect and directing his career towards that of the development sector. On his spare time, he enjoys traveling, following adventures, volunteering and playing music.
https://www.buildabroad.org/2017/02/07/straw-bale-construction/
On – 07 Feb, 2017 By Chad Johnson
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Renewable Energy – The Precise Facts to Know
In a simple word, renewable energy comes from natural cycles and systems, turning the ever-present energy around us into functional forms. Renewable (alternative) energy is mostly cleaner than energy from nonrenewable options such as natural gas, petroleum, and coal. But right now in the U. S. over many of these of our energy still comes from nonrenewable resources.
Such as the name says, green energy can be refilled continuously. Its sources include radiant energy like sun, thermal energy like geothermal, chemical processes like biomass, gravitational energy like hydropower, and motion energy like wind.
A few of the key sources of power include:
Solar
Solar electricity is able to one day solve much of the energy needs, but that day is still very remote. Still, solar technology has become more efficient and cost-effective every year, and it is the fastest-growing kind of renewable energy.
Wind
Wind power is one of the greenest technologies, and also one of the most abounding and cost-competitive energy resources, rendering it a viable option to the non-renewable powers that harm our health and threaten the environment. Yet wind power is unreliable as a frequent source of electricity, impacts great tracts of land, and it is unavailable where wind is intermittent.
Hydro
Harnessing the kinetic power of moving normal water to generate electricity is the major source of renewable power in the USA and worldwide. Hydropower can be a sustainable and nonpolluting power source that can help decrease our dependence on fossil fuels and minimize the threat of global warming, but is limited to areas with large and regular drinking water supplies.
Bio-fuels
Ethanol is the product of crops full of sugar or starch, while biodiesel is the product of crops with high essential oil content. Both are natural carbon fuel, and both provide practical powers which may have not yet reached their full probable. Scientists continue refining food stocks to obtain higher efficiencies.
Geothermal
Heat from the earth, or geothermal energy, is cost effective, reliable, and clean, but is mostly limited to areas near tectonic plate limits. Some progress has recently been made recently in broadening the range of geothermal resources, but geothermal electric power remains a limited solution to our energy needs.
Ocean
Another form of kinetic power technology, the ocean’s frequent motion by way of dunes, tides, and currents is an effective and clean energy resource. Like other hydro power, though, its geographic range is limited.
Renewable Energy and Environment/Climate Change –
There is general arrangement among the world’s major economies that it is essential to reduce carbon dioxide emissions by 50% by 2050. And with energy-related Carbon Dioxide accounting for 61 percent of global greenhouse gas emissions today, the energy sector must be at the heart of change.
Europe is committed to a 30 percent reduction by the year 2020 and a 60 to 80 percent decline by 2050, under stipulation that additional developing nations also obligate. To accomplish the things, it will require a huge sum of USD 22 trillion in global energy investments over the next 25 to 30 years.
http://greenhoper.net/info/renewable-energy-the-precise-facts-to-know/
On – 10 Feb, 2017 By greenhoper
