It is fact, that now days households and other living areas in which people live, or reside most of the time, contribute CO2 emission and green house effects as much as global warming, which threatens to all humans and their health, as well as natural resources which balance is disturbed a long time ago. Sustainable house or Green house or Eco House is one of possible solutions, which with one part can contribute in solving of this global burning issue.
There is a question, how this house, or what makes it good for living! That is house which is energy efficient by itself, environmentally healthy, respectful for the natural environment, comfortable for family life, in other words to be sustainable designed, built of green or recycled materials, and this house should use alternative energy resources.
In the broad context, sustainable architecture seeks to minimize the negative environmental impact of buildings by enhancing efficiency and moderation in the use of materials, energy, and development space. Most simply, the idea of sustainability, or ecological design, is to ensure that our actions and decisions today do not inhibit the opportunities of future generations.This term can be used to describe an energy and ecologically conscious approach to the design of the built environment.
Sustainable homes have three key elements.
1. Environmental sustainability
The house is designed to reduce greenhouse gas
emissions, save water and energy and reduce waste
during construction and the house’s lifetime.
2. Social sustainability / universal design
The house is designed to prevent injuries through built-in
safety features. It has security elements to reduce crime
and improve the occupants’ sense of security. Features
are also used to provide flexibility and comfort for people
of varying abilities and at different life stages, including
children and people with limited mobility.
3. Economic sustainability
The house is designed to save money during construction
and over the lifetime of the house. Careful planning avoids
the need for major future renovations and reduces costs
associated with energy use, water use and maintenance.
One central and often ignored aspect of sustainable architecture is building placement. Although many may envision the ideal environmental home or office structure as an isolated place in the middle of the woods, this kind of placement is often detrimental to the environment. First, such structures often serve as the unknowing frontlines of suburban sprawl. Second, they usually increase the energy consumption required for transportation and lead to unnecessary auto emissions. Ideally, most building should avoid suburban sprawl in favor of the kind of light urban development. Careful mixed use zoning can make commercial, residential, and light industrial areas more accessible
Social sustainability in architecture
The building structure must also be considered. Cost/effectiveness is an important issue in sustainable architecture projects, and one of the most efficient designs herein is the Public housing approach. This approach lets everyone have their own sleeping/recreation space, yet incorporate communal spaces eg. Mess halls, Latrines, public showers...
Sustainable design can help to create a sustainable way of living within a community. While the existing social constructs can be seen to influence architecture, the opposite can also be true. An overtly socially sustainable building, if successful, can help people to see the benefit of living sustainably. The same can be said for environmentally sustainable design, in that architecture can lead the way for the greater community.
Art can be a powerfully positive social force. It can help to reduce stress in many situations, lowering the risk of stress-related health problems, both physical and mental.
The passive house standard combines a variety of techniques and technologies to achieve ultra-low energy use.
Energy efficiency over the entire life cycle of a building is the most important single goal of sustainable architecture. Architects use many different techniques to reduce the energy needs of buildings and increase their ability to capture or generate their own energy.
Heating, Ventilation and Cooling System Efficiency
The most important and cost effective element of an efficient heating, ventilating, and air conditioning system is a well insulated building. A more efficient building requires less heat generating or dissipating power, but may require more ventilation capacity to expel polluted indoor air.
Significant amounts of energy are flushed out of buildings in the water, air and compost streams. Off the shelf, on-site energy recycling technologies can effectively recapture energy from waste hot water and stale air and transfer that energy into incoming fresh cold water or fresh air. Recapture of energy for uses other than gardening from compost leaving buildings requires centralized anaerobic digesters.
Site and building orientation have some major effects on a building's efficiency.
Passive solar building design allows buildings to harness the energy of the sun efficiently without the use of any active solar mechanisms such as photovoltaic cells or solar hot water panels. Typically passive solar building designs incorporate materials with high thermal mass that retain heat effectively and strong insulation that works to prevent heat escape. Low energy designs also requires the use of solar shading, by means of awnings, blinds or shutters, to relieve the solar heat gain in summer and to reduce the need for artificial cooling. In addition, low energy buildings typically have a very low surface area to volume ratio to minimize heat loss. This means that sprawling multi-winged building designs (often thought to look more "organic") are often avoided in favor of more centralized structures.
Windows are placed to maximize the input of heat-creating light while minimizing the loss of heat through glass, a poor insulator. In the northern hemisphere this usually involves installing a large number of south-facing windows to collect direct sun and severely restricting the number of north-facing windows. Certain window types, such as double or triple glazed insulated windows with gas filled spaces, provide much better insulation than single-pane glass windows. Preventing excess solar gain by means of solar shading devices in the summer months is important to reduce cooling needs. Deciduous trees are often planted in front of windows to block excessive sun in summer with their leaves but allow light through in winter when their leaves fall off. Light shelves are installed to allow the sunlight in during the winter (when the sun is lower in the sky) and keep it out in the summer (when the sun is high in the sky). Evergreen plants are often planted to the northbuildings to shield against cold north winds.
In colder climates, heating systems are a primary focus for sustainable architecture because they are typically one of the largest single energy drains in buildings.
In warmer climates where cooling is a primary concern, passive solar designs can also be very effective. Masonry building materials with high thermal mass are very valuable for retaining the cool temperatures of night throughout the day. In addition builders often opt for sprawling single story structures in order to maximize surface area and heat loss. Buildings are often designed to capture and channel existing winds, particularly the especially cool winds coming from nearby bodies of water. Many of these valuable strategies are employed in some way by the traditional architecture of warm regions, such as south-western mission buildings.
In climates with four seasons, an integrated energy system will increase in efficiency: when the building is well insulated, when it is sited to work with the forces of nature, when heat is recaptured (to be used immediately or stored), when the heat plant relying on fossil fuels or electricity is greater than 100% efficient, and when renewable energy is utilized.
Alternative energy Systems
Active solar devices such as photovoltaic solar panels help to provide sustainable electricity for any use. Electrical output of a solar panel is dependent on orientation, efficiency, latitude, and climate— solar gain varies even at same latitude. Typical efficiencies for commercially available PV panels range from 4% to 28%. The low efficiency of certain photovoltaic panels can significantly effect the payback period of their installation.Roofs are often angled toward the sun to allow photovoltaic panels to collect at maximum efficiency. For any solar panel, a true-south facing orientation maximizes yield. If true-south is not possible, solar panels can produce adequate energy if aligned within 30° of south. However, at higher latitudes, winter energy yield will be significantly reduced for non-south orientation.
To maximize efficiency in winter, the collector should be angled above horizontal Latitude + 15°. To maximize efficiency in summer, the angle should be Latitude - 15°. However, for an annual maximum production, the angle of the panel above horizontal should be equal to its latitude.
Wind turbine systems for homes are one of the more cost effective forms of generating electricity from a renewable energy source if you have the right site. Wind turbines begin operating when winds reach 8 mph, achieve energy production capacity at speeds of 32-37 mph, and shut off to avoid damage at speeds exceeding 55 mph. The energy potential of a wind turbine is proportional to the square of the length of its blades and to the cube of the speed at which its blades spin. Though wind turbines are available that can supplement power for a single building, because of these factors, the efficiency of the wind turbine depends much upon the wind conditions at the building site. For these reasons, for wind turbines to be at all efficient, they must be installed at locations that are known to receive a constant amount of wind (with average wind speeds of more than 15mph), rather than locations that receive wind sporadically. A small wind turbine can be installed on a roof. Installation issues then include the strength of the roof, vibration, and the turbulence caused by the roof ledge. Small-scale rooftop wind turbines have been known to be able to generate power from 10% to up to 25% of the electricity required of a regular domestic household dwelling. Turbines for residential scale use are available. They are usually approximately 7 feet (2 m) to 25 feet (8 m) in diameter and produce electricity at a rate of 900 watts to 10,000 watts at their tested wind speed. It is possible to have a system which only gets it power from wind, however, many people combine getting power from a wind turbine with getting power from a solar electric system. The two technologies are often complimentary: when there's little sun (e.g. during the winter or when it's overcast), there's often more wind and vice versa.
Typical Wind turbine for installaion on houses www.wsmweather.co.uk/?p=1375
Solar Water Heating
Solar water heaters—also called solar domestic hot water systems—can be a cost-effective way to generate hot water for your home. They can be used in any climate, and the fuel they use—sunshine—is free .
There are two types of solar water systems- active and passive.There are also two types of circulation, direct circulation systems and indirect circulation systems. Direct circulation systems loop the domestic water through the panels. They should not be used in climates with temperatures below freezing. Indirect circulation loops glycol or some other fluid through the solar panels and uses a heat exchanger to heat up the domestic water.
The two most common types of collector panels are Flat-Plate and Evacuated-tube. The two work similarly except that evacuated tubes do not convectively lose heat, which greatly improves their efficiency (5%-25% more efficient). With these higher efficiencies, Evacuated-tube solar collectors can also produce higher-temperature space heating, and even higher temperatures for absorption cooling systems.
Electric-resistance water heaters that are common in homes today have an electrical demand around 4500 KWh/year. With the use of solar collectors, the energy use is cut in half. The up-front cost of installing solar collectors is high, but with the annual energy savings, payback periods are relatively short.
Home Solar Water Heating www.urbansprout.co.za/article/ethical_consume
Geothermal Heat Pumps
Geothermal energy is the heat from the Earth. It's clean and sustainable. Resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the Earth's surface, and down even deeper to the extremely high temperatures of molten rock called magma. Air-source heat pumps (ASHP) can be thought of as reversible air conditioners. Like an air conditioner, an ASHP can take heat from a relatively cool space (e.g. a house at 70°F) and dump it into a hot place (e.g. outside at 85°F). However, unlike an air conditioner, the condenser and evaporator of an ASHP can switch roles and absorb heat from the cool outside air and dump it into a warm house.
Air-source heat pumps are inexpensive relative to other heat pump systems. However, the efficiency of air-source heat pumps decline when the outdoor temperature is very cold or very hot; therefore, they are only really applicable in temperate climates.
For areas not located in temperate climates, ground-source (or geothermal) heat pumps provide an efficient alternative. The difference between the two heat pumps is that the ground-source has one of its heat exchangers placed underground—usually in a horizontal or vertical arrangement. Ground-source takes advantage of the relatively constant, mild temperatures underground, which means their efficiencies can be much greater than that of an air-source heat pump. The in-ground heat exchanger generally needs a considerable amount of area. Designers have placed them in an open area next to the building or underneath a parking lot.
Energy Star ground-source heat pumps can be 40% to 60% more efficient than their air-source counterparts. They are also quieter and can also be applied to other functions like domestic hot water heating.
In terms of initial cost, the ground-source heat pump system costs about twice as much as a standard air-source heat pump to be installed. However, the up-front costs can be more than offset by the decrease in energy costs. The reduction in energy costs is especially apparent in areas with typically hot summers and cold winters.
Other types of heat pumps are water-source and air-earth. If the building is located near a body of water, the pond or lake could be used as a heat source or sink. Air-earth heat pumps circulate the building’s air through underground ducts. With higher fan power requirements and inefficient heat transfer, Air-earth heat pumps are generally not practical for major construction.
As water conservation becomes more important, people look to use water more wisely. Using rain water can be a simple and effective way to cut down on household water usage and save money. The key to a rain water collection system is a rain barrel. You can then collect it in a barrel or tank once it comes down through the roof gutter system. Then you can use the water for your garden, or if you want to use the water for drinking, you'll want to read more about methods of filtering and cleaning the water (common methods include UV light, ozone, and chlorination). Rainwater systems are simple to construct from inexpensive local materials, and are potentially successful in most habitable locations. Roof rainwater is usually of good quality and does not require treatment before consumption. Household rainfall catchment systems are appropriate in areas with an average rainfall greater than 200mm per year. Roof catchment systems channel rainwater that falls onto a roof into storage via a system of gutters and pipes. The first flush of rainwater after a dry season should be allowed to run to waste as it will be contaminated with dust, bird droppings etc. Roof gutters should have sufficient incline to avoid standing water. They must be strong enough, and large enough to carry peak flows. Storage tanks should be covered to prevent mosquito breeding and to reduce evaporation losses, contamination and algal growth. Rainwater harvesting systems require regular maintenance and cleaning to keep the system hygienic and in good working order.
A domestic rooftop rainwater harvesting system
Typical Rainwatre system www.res-devon.co.uk/rainwater-harvesting.asp
Greywater is wastewater from bathtub, shower drain, sinks, washing machines, and dishwashers. Greywater accounts for 60% of the outflow produced in homes. It contains little or no pathogens and 90% less nitrogen than black water (toilet water). Because of this, it does not require the same treatment process. By designing plumbing systems to separate it from blackwater, greywater can be recycled for irrigation, toilets, and exterior washing, resulting in water conservation. When planned into new residential construction, the home's wastewater treatment system can be significantly reduced, resulting in cost and space savings.
Systems generally consist of a three-way diverter valve, a treatment assembly such as a sand filter, a holding tank, a bilge pump, and an irrigation or leaching system. The holding tank cools the water and temporarily holds it back from the drain hose. Systems can either be custom designed and built, or purchased as a package. Techniques include recessed or raised planter soilboxes, water injection without erosion, gravity or pressure leach chamber, and irrigated greenhouses. Some system components can retrofit existing irrigation systems.
Typical greywater system www.humboldt.edu/~sej26/CCAT/grey.html
The mass of a building (often referred to as 'thermal mass' in relation to energy efficiency) is a building's capability to absorb, store and regulate heat internally.
Buildings with a high mass take a long time to warm up and then long time to cool down. Buildings with low mass heat up quickly, but give up their heat-gain quickly, too.
Concrete, stone, brickwork, and timber have a high density, making them ideal for high-mass buildings; areas with large windows and wide air spaces heat up and cool down quickly.
Energy-efficient homes use high-mass materials. This is a natural energy efficiency technique as it keeps the building cool in the scorching summer months and keeps the heat indoors in cooler winter months. If you want your home to be energy efficient, build, extend or renovate using high-mass materials. This means that the solar gain during the day will be absorbed and released slowly overnight. Building solid walls (or stone floors with dark colored tiles) behind south-facing windows will help to create natural 'heaters' in your home: they will absorb the heat through the window during the day and release the heat overnight.
Another advantage of high-mass buildings is that they experience a much lower temperature fluctuation between day and night: this will make your home more comfortable to live in, reduce your heating and cooling costs and make more efficient use of your water heater and some other high-consumption appliances (e.g. refrigerators and freezers).
Building materials typically considered to be 'green' include rapidly renewable plant materials like bamboo (because bamboo grows quickly) and straw, lumber from forests certified to be sustainably managed, ecology blocks, dimension stone, recycled stone, recycled metal, and other products that are non-toxic, reusable, renewable, and/or recyclable (e.g. Trass, Linoleum, sheep wool, panels made from paper flakes, compressed earth block, adobe, baked earth, rammed earth, clay, vermiculite, flax linen, sisal, seagrass, cork, expanded clay grains, coconut, wood fibre plates, calcium sand stone, concrete (high and ultra high performance, roman self-healing concrete).
The materials common to many types of natural building are clay and sand. When mixed with water and, usually, straw or another fiber, the mixture may form cob or adobe (clay blocks). Other materials commonly used in natural building are: earth (as rammed earth or earth bag), wood (cordwood or timber frame/post-and-beam), straw, rice-hulls, bamboo and rock. A wide variety of reused or recycled materials are common in natural building, including urbanite (salvaged chunks of used concrete), tires, tire bales, discarded bottles and other recycled glass.
Several other materials are increasingly avoided by many practitioners of this building approach, due to their major negative environmental or health impacts. These include unsustainably-harvested wood, toxic wood-preservatives, portland cement-based mixes, paints and other coatings which off-gas volatile organic compounds (VOCs), and some plastics, particularly polyvinyl chloride (PVC or "vinyl") and those containing harmful plasticizers or hormone-mimicking formulations.
A wall is a usually solid structure that defines and sometimes protects an area. Most commonly, a wall delineates a building and supports its superstructure, separates space in buildings into rooms, or protects or delineates a space in the open air. There are three principal types of structural walls: building walls, exterior boundary walls, and retaining walls.
Cob or cobb is a building material consisting of clay, sand, straw, water, and earth, similar to adobe. Cob is fireproof, resistant to seismic activity, and inexpensive. It can be used to create artistic, sculptural forms and has been revived in recent years by the natural building and sustainability movements. Cob is an ancient building material, that may have been used for construction since prehistoric timesCob structures can be found in a variety of climates across the globe.
Adobe is a type of mudbrick also used today to save energy and is an environmentally safe way to insulate a house. This type of house tends to stay cool in the summer and warm in the winter.Adobe is a natural building material made from sand, clay, and water, with some kind of fibrous or organic material (sticks, straw, dung), which is shaped into bricks using frames and dried in the sun. It is similar to cob and mudbrick. Adobe structures are extremely durable and account for some of the oldest extant buildings on the planet.In hot climates, compared to wooden buildings, adobe buildings offer significant advantages due to their greater thermal mass, but they are known to be particularly susceptible to seismic damage in an event such as an earthquake.
Adobe / Mud brick www.ecobob.co.nz/_ImgUser
Cordwood construction is a term used for a natural building method in which "cordwood" or short lengths pieces of debarked tree are laid up crosswise with masonry or cob mixtures to build a wall. The cordwood, thus, becomes infill for the walls, usually between posts in a timber frame structure. Cordwood masonry can be combined with other methods (e.g., rammed earth, cob or light clay) to produce attractive combinations. Cordwood masonry construction provides a relatively high thermal mass, which makes it easy to heat and coo.
Rammed earth, also known as taipa, pisé de terre or simply pisé, is a technique used in the building of walls using the raw materials of mud, chalk, lime and gravel. It is an ancient building method that has seen a revival in recent years as people seek more sustainable building materials and natural building methods. Because of the nature of the materials used it is incombustible, thermally insulating and very strong and hardwearing. It also has the added advantage of being a simple way to construct walls. Traditionally, rammed earth buildings are common in arid regions where wood is in scarce supply.
Because rammed earth structures utilize locally available materials, they typically have a low embodied energy rating and generate very little waste. Earth used for building is a widely-available resource and harvesting it for use in construction has minimal environmental impact.
Rammed earth interior
Timber framing is now a modern method of construction, Ideally suited to mass house building as well as public buildings. In conjunction with a number of natural insulations and timber cladding or modern lime renders, it is possible to quickly construct a high performance, sustainable building, using completely natural products. The benefits are many — the building will perform better over its lifespan, waste is reduced (much can be re-cycled, composted or used as fuel). Timber frame structures are frequently used in combination with other natural building techniques, such as cob, straw bale, or cordwood/masonry.Advantages:the use of timber framing in buildings offers various aesthetic and structural benefits the timber frame structure goes up quickly in its modern incarnation the timber frame can give the home owner the ability to make a creative statement through the use of design and specialty touches like carvings of favorite quotes and incorporating timbers from heirloom structures, like a barn from a family homestead.Disadvantages: some possible disadvantages of wood as opposed to some other building materials include: Noise from footsteps in adjacent rooms above, below, and on the same floor in such buildings can be quite audible. The possibility of infestation by insects such as termites, cockroaches or powder post beetles, or by other pest animals such as mice and rats. Wood burns more readily than some other materials, making timber-frame buildings somewhat more susceptible to fire damage, although this idea is not universally accepted.
Timber frame www.timberstructures.net
Straw-bale construction is a building method that uses bales of straw (commonly wheat, rice, rye and oats straw) as structural elements, insulation, or both. This construction method is commonly used in natural building or "green" construction projects. Straw-bale construction has some advantages over conventional building systems because of the renewable nature of straw, its cost, easy availability, and its high insulation value.
Straw-bale construction www.supergreenme.com
Sustainable flooring is produced from sustainable materials (and by a sustainable process) that reduces demands on ecosystems during its life-cycle. This includes harvest, production, use and disposal. It is thought that sustainable flooring creates safer and healthier buildings and guarantee a future for traditional producers of renewable resources that many communities depend on. Below are examples of available, though less well-known, eco-friendly flooring options.
Sustainable flooring www.ecofriend.org
Bamboo flooring is made from a fast growing renewable timber (technically grass). It is natural anti-bacterial, water-resistant and extremely durable.
Cork flooring is made by removing the bark of the Cork Oak (Quercus Suber) without harming the tree (if harvested correctly); it is a truly renewable resource. It is naturally anti-microbial and has excellent insulation properties, ensuring minimal heat loss and comfortable warm walking surface. Cork is resilient and ‘springs back’ preventing imprints due to heavy traffic and furniture, it also provides excellent noise insulation. Cork is low in VOC (volatile organic compound) emissions, however it is important to check the finish applied. Cork is not suitable for bathrooms, as it absorbs moisture.
Cork flooring www.furniturehomedesign.com/.../flooring
Linoleum is made from dried and milled flax seeds mixed with other plant material (pine resins, wood flour, ground cork) with a jute backing, all completely natural materials which come from renewable sources and are 100% biodegradable. All by products and waste is milled and used. Linoleum does not fade, as the pigments are embedded in the structure. It is anti-static, repelling dirt, dust and other small particles, making it hypoallergenic – for this reason it is often used by people with respiratory issues (asthma, allergies). It is also fire-resistant and does not require additional fire-retardants finish.
Rubber flooring is made from a rubber tree, a 100% renewable resource. It is easy to install and maintain, is anti-static and provides effective sound insulation and vibration reduction. Rubber flooring is also resistant to fading and cigarette burns. Some rubber flooring is made from synthetic rubber, this is not a sustainable product.
Rubber flooring www.ehow.com/way_5460070_recycled-flooring-id.
Natural and Recycled Carpet. There are carpets that are sustainable, using natural fibers such as sisal, wool, jute and coconut husk. It is also possible to have carpet made completely from recycled polyethylene terephthalate used for food/drink containers. This is sustainable and it reduces material sent to landfill; further it uses dyeing methods that are less polluting and require less energy than other flooring. This flooring is sustainable when used alongside eco-friendly adhesive as some products may have toxic finishes added (stain/fire proofing) that are not considered to be sustainable.
Recycled Carpet www.durablecorp.com/.../d/u/duraridge2.jpg
Frames can significantly affect a windows performance, depending on the type of frame material. Wood frames are energy efficient, and can be sourced from a certified sustainable supplier, but can also be expensive and need to be painted regularly to protect them from water damage. Fibreglass frames are low maintenance and energy-efficient but can also be expensive. Aluminium frames are inexpensive but conduct heat easily and are therefore less energy efficient than other options.
One of the most popular materials for framing is PVC, also called uPVC, and PVCu. These are made from vinyl and are inexpensive, energy efficient and low maintenance. They do not need to be painted and are highly resistant to moisture. Some vinyl frames have been insulated to give improved thermal performance.
Frame of Wood www.efficientwindows.org/images/frame_wood.gif
Frame of Recycled PVC www.buildingdesign-news.co.uk/2009/images-200..
Energy efficient windows have two or more panes of glass separated by an air gap to slow heat transfer and provide noise insulation. These are known as double paned or insulated windows. Traditionally air or dry nitrogen was used between the panes, but recent models use low conductance gas fills of argon or krypton that gives even better thermal performance and significantly lowers the U-value.
Another new development in window technology is low-emittance coating also known as low-e. These are microscopically thin layers of metal or metallic oxide that are coated onto the window glazing. Different types of coating have different properties, but all are designed to lower heat flow through the window - some reflect heat back into the building and others reflect heat back outside.
Spacers are used in between the layers of glass in a window, to hold them together at the required distance. Conventional spacers were made from aluminium, but because of their high conductivity they provided poor thermal insulation and created condensation problems around the window edges. New spacer products, known as warm spacer technology, or warm edge spacers, have been developed from materials that have a low conductivity rate and high thermal efficiency, and include fiberglass, vinyl, silicone foam and reinforced thermoplastic. Some warm edge spacers incorporate a thermal break in their structural design.
Window technology has undergone a revolution in the last twenty years. Using a combination of gas filled double-glazing, glass coatings, thermally improved edge spaces and PVC framing it is now possible to adjust solar gain, reduce condensation, prevent air leakage and improve the comfort of an indoor environment while offering the homeowner huge savings in energy and money. More importantly, energy efficient windows reduce carbon emissions and help to address global climate change. Used in combination with other green building methods and materials, they are a good choice for a brighter, sustainable future.
Double-pane Windows - These energy efficient windows can reduce heating bills by 34% in cold climates, and 38% in warm climates. www.uwsp.edu/.../double-pane%20window.j
A roof is the covering on the uppermost part of a building. A roof protects the building and its contents from the effects of weather. The characteristics of a roof are dependent upon the purpose of the building that it covers, the available roofing materials and the local traditions of construction and wider concepts of architectural design and practice and may also be governed by local or national legislation.
The elements in the design of a roof are:
The material of a roof may range from banana leaves, wheaten straw or seagrass to lamininated glass, aluminium sheeting and precast concrete. In many parts of the world ceramic tiles have been the predominant roofing material for centuries.
Japan, rice straw thatch.
In selecting material for roof covering one should take into account its weight (heavier material requires larger support members), its durability (e.g. how well can it tolerate high and low temperatures and for how long), its effect on water falling on the roof if the water is being captured (for example, will gravel from shingles build up sediment in a cistern or do roof materials leach into the water?), the heat-holding qualities of the roof material (does it heat up and stay hot into the night?), as well as cost, fire rating, maintainability, and installation characteristics.
Slate, clay, and cementitious roof materials offer excellent durability but are heavy. Fiber-cement composite roof materials are somewhat lighter and use fiber materials resourcefully. Some use waste paper as well as wood fiber. Many have 60 year warranties.
Natural Slate Roof www.bestroofcompanies.com/images/stories/guid
Metal roof materials, steel and aluminium contain high percentages of recycled content, up to 100% in many aluminum products. An additional advantage is that these materials are easily recycled in their post-use as well as lightweight and durable.
Asphalt shingles use recycled, mixed paper in their base and some use reclaimed minerals in the surface aggregate. This type of material does not last as long as the others mentioned above. Recycled plastic roof materials are starting to be introduced as a lightweight option.
The construction of a roof is determined by its method of support and how the underneath space is bridged and whether or not the roof is pitched. The pitch is the angle at which the roof rises from its lowest to highest point. Most domestic architecture, except in very dry regions, has roofs that are sloped, or pitched. The pitch is partly dependent upon stylistic factors, but has more to do with practicalities. Some types of roofing, for example thatch, require a steep pitch in order to be waterproof and durable. Other types of roofing, for example pantiles, are unstable on a steeply pitched roof but provide excellent weather protection at a relatively low angle. In regions where there is little rain, an almost flat roof with a slight run-off provides adequate protection against an occasional downpour.
The durability of a roof is a matter of concern because the roof is often the least accessible part of a building for purposes of repair and renewal, while its damage or destruction can have serious effects.
A roofing system that can deliver high solar reflectance (the ability to reflect the visible, infrared and ultraviolet wavelengths of the sun, reducing heat transfer to the building) and high thermal emittance (the ability to radiate absorbed, or non-reflected solar energy) is a cool roof. Most cool roofs are white or other light colors.
A green roof is a roof of a building that is partially or completely covered with vegetation and soil, or a growing medium, planted over a waterproofing membrane. It may also include additional layers such as a root barrier and drainage and irrigation systems. Also known as “living roofs,” green roofs serve several purposes for a building, such as absorbing rainwater, providing insulation, creating a habitat for wildlife, and helping to lower urban air temperatures and combat the heat island effect.
There are two types of green roofs: intensive roofs, which are thicker and can support a wider variety of plants but are heavier and require more maintenance, and extensive roofs, which are covered in a light layer of vegetation and are lighter than an intensive green roof.
Green roof www.naturalbalancedevelopment.com/.../msl/6.gif
Green Roof www.santamonicapropertyblog.com/wp-content/up.
Because it is hidden in our walls, most of us do not really think about insulation or what it’s made of. But more and more people are looking to “green” options for insulating their homes and buildings, not only because it’s healthier for the occupants, but also because the manufacture and use of green insulation is better for the environment. Mainstream insulation can contain fiberglass, formaldehyde, and other toxic components. Here are some examples of eco-friendly, healthy insulation materials.
Jeans - Yes, jeans – as in blue jeans. Some insulation companies recycle the waste denim from blue jeans manufacturers and make it into insulation. This cotton fiber is as effective as fiberglass, and works for thermal as well as noise insulation. It is treated with borate, a non-toxic chemical that does not outgas and acts as a fire retardant and mold inhibitor.
Wool -Another common clothing item, wool makes excellent insulation. You have the option of having it treated chemically to reduce the risk of insect infestation. It has been used successfully without being so treated, and if you want to avoid chemicals altogether, you can try it untreated. Wool is naturally resistant to fire.
Mineral Wool www.lowenergyhouse.com/glass-wool.htm
Sheep Wool Insulation www.natureproinsulation.co.uk/sheepswool.htm
Sheep Wool Insulation www.natureproinsulation.co.uk/sheepswool.htm
Cellulose is made from recycled or finely-shredded newspaper. There are options as to its installation: it can be blown into crevices and walls, and it’s also available in boards and pads. It is also chemically treated with non-toxic substances to reduce susceptibility to fire and mold.
Cellulose Insulation www.applegateinsulation.com/
Hemp - Naturally resistant to insects, hemp does not need to be chemically treated with insecticide. It is fairly dense and offers insulating properties similar to wool.
Hemp insulation www.hemcore.co.uk/insulation.htm
Straw - One of the oldest insulators, straw is making a comeback. Tightly-bound bales are stacked within wall studs and covered with plaster. Baled in this way, straw is fire-resistant but prone to moisture absorption, so it’s not a good option for humid climates.
Stawe bale insulation article-niche.com/launch/Straw-Bale-Construct.
Spray foam - There are such things as eco-friendly, spray foam insulations. Water-based spray is a mix of carbon dioxide and water, and it is sprayed into spaces where it swells and fills the space like traditional, synthetic foams. Another kind of spray foam insulation is made with a combination of naturally-derived magnesium dioxide and compressed air. It is mold and fire resistant, and is particularly good insulation against noise.Whether you are re-insulating an existing home or building your own structure from the ground up, there are quite a few options for non-toxic insulation that will improve your indoor air quality and be easier on the planet.
Spray Foam insulation www.sacramento-home-repairs.com/images/spray
Earth - Earth is one of the best insulators.
Natural insulation - earth
Eco Friendly Gardens and Landscapes
There are a number of sensible reasons to employ the use of 'eco friendly' garden and landscape techniques when you build or develop your home.
Protection from the Sun
Creating shade around your home by the use of trees and shrubs is the perfect way to prevent excess heat from entering your home through windows and roofs, especially in exceptionally hot climates. Keeping the interior of your home cooled down naturally will save energy by reducing the amount of air conditioning required to cool the indoor living areas.
Water conservation is of primary concern, especially in Mexico's hotter climates and desert regions. The use of certain breeds of grass as well as alternative landscaping materials that don't require water (e.g. bark chipping, pebble stones) will provide you with a means to create an attractive landscape around your home without the need to use up scarce water supplies.
Wind breaks help to prevent the wind from carrying heat away from your house, in climates where indoor heat preservation is desirable. The most common form of wind breaks are shrubs and vines planted to divert winds away from the house walls. Another technique is to use 'earth breaks' by either creating mounds of earth in strategic places or using the land's natural topography to create wind breaks for the house.
Reducing Electricity Consumption
By employing the use of solar-powered lighting for your garden (if you use garden lights, buy the stand-alone type which charge up during the daylight and use that stored power to illuminate the bulb at night) and reducing the amount of water required in your garden, especially in areas where water is more scarce, energy may be conserved through less us of electricity (e.g. water pumps, water delivery to your home, sprinkler systems). A carefully thought-out garden and landscape can provide beautiful surroundings for your home and save energy. See the Landscape ecology link at the foot of this guide for more details.