Sustainable Ecological Housing Fabric - Essay Example

Sustainable/Ecological Housing fabric Introduction When the SAP calculation was introduced into the Building Regulations in 1995, it was easier to score more points (ie a higher SAP rating) by specifying an efficient heating system than by improving the building envelope. In the Code for Sustainable Homes today, greater emphasis is given to the construction of the fabric. Thermal mass, the type and position of insulation, cold bridging and infiltration are important design elements to consider for instance. The architecture of new housing in the UK may also be fundamentally different to traditional housing, as demonstrated by projects like BedZed in Surrey and the Tree House in Clapham, South London. However, the sense of place suggested by CABE has also encouraged designs with strong references to local vernacular styles. Numerous issues therefore impact on design and construction today. It is imperative at this juncture that we understand what some certain things are all about Sustainable Construction Sustainable construction can or is defined as "the process of creating and responsibly managing a healthy built environment based on two factors which are resource efficient and ecological principles". The aim of Sustainable designed buildings is to reduce the effect of their impact on our environment through energy and resource efficiency. The following principles are included: minimizing the use of toxins to the lowest level non-renewable resource consumption should be minimized Environmental Architecture Healthful Interior Environment. All possible measures are to be taken to ensure that materials and building systems do not emit toxic substances and gasses into the interior atmosphere. Additional measures are to be taken to clean and revitalize interior air with filtration and plantings. Three principles of an environmental architecture include: Energy Efficiency. All possible measures are to be taken to ensure that the building's use of energy is minimal. Cooling, heating and lighting systems are to use methods and products that conserve or eliminate energy use. Other materials and products are to be considered based on the toxic waste out put of production. Environmental Form. All possible measures are to be taken to relate the form and plan of the design to the site, the region and the climate. Measures are to be taken to "heal" and augment the ecology of the site. Accommodations are to be made for recycling and energy efficiency. Measures are to be taken to relate the form of building to a harmonious relationship between the inhabitants and nature. (Thomas A. Fisher, AIA, November, 1992). Energy Efficiency Economic (saving money), ecological (reducing resource exploitation and emissions) and social (reducing fuel poverty) Are the benefits derived from the energy-efficient sitting and design of buildings. An explicit energy strategy should be possessed by every new development ideal. Throughout the design process, energy assessment conservation measures can be done early through computer energy simulations. Many alternative concepts for building form, envelope and landscaping, focusing on minimizing peak energy loads, demand and consumption etc are collaborated by the expanded design team. In energy conservation, and their construction costs, computer energy simulation is used to assess their effectiveness. Simulations are made use of to refine designs and properly ensure that energy-conservation and capital cost goals are met; and to demonstrate compliance with regulatory requirements. Architecture and construction of new housing in the UK can be vitally dissimilar to traditional housing, as demonstrated by the three case studies that have been shown above, including Abode Newhall in Harlow, Ashley Vale Self-build in Bristol, Great Bow Yard in Langport Somerset. These case studies have sustainable, low-energy and ecological features. They have also encouraged design with strong references to local vernacular styles. This report will look at one of these two case studies and report on the sustainable characteristics of this development's building structure with aid of sketches. It will explore the structure in detail and explain issues, problems that have occurred and how they have been solved. It will also look at how this development has improved and benefited the environment and how other developments can take benefit from this type of construction. The case study that has been chosen in order for this report is case study 2 Great Bow Yard in Langport Somerset. Sets out to reduce water consumption and CO2 emissions from fossil fuels is the Great Bow Yard project. State of the art domestic scale energy saving technologies has been installed. The project is a unique mixed-use development of 12 beautifully designed eco- homes, alongside workshops and offices. Sustainable sourced materials have been used in the building process; moreover great effort was made to ensure that toxic chemicals were avoided. The insulation is far above normal standards for UK construction and also incorporates renewable energy sources and energy-saving devices The homes have been designed to: - - Reduce substantially the rate of carbon emissions and water consumption - Measure up to the BRE EcoHomes rating "Excellent" - Create a positive impact on the local economy (http://www.ecoshomes.co.uk/settingthestandard.html) Warm in winter There is no need of a background heating system because all the homes have double the insulation that is currently required by the building regulations. A small and efficient condensing boiler has been installed; it operates off the mains gas supply. In some houses it heats standard wall radiators, in others; under floor heating has been installed at the request of the owners. In other cases, wood burning stoves are fitted by some owners who wanted the option of reducing the demand on their boiler and have a real fireplace in their living room. Sun and wind electricity Likely to rise substantially is the costs of electricity over the next fifteen years. And the incidence of power cuts is also very likely to increase at the same time. Developing quickly is the technology for using the wind and the sun to provide an alternative source of power and in the three town houses at Great Bow Yard, efforts are made to duct for photovoltaic panels in order to provide up to 1.5kw of power to each house, also provisions are in place to add a domestic scale wind turbine for the purpose of supplementing the sun's energy over the winter months. The panels are mounted with special DC cable linking direct to a specialist meter on the South facing roof planes. The sun hot water Liable to reduce water-heating costs by 100 p.a. is the solar thermal panels mounted on the south facing elevations of the North Wing, on the assumption of average domestic use for two people at current prices for gas/electricity. If, the prices of gas and electricity double in the next fifteen years, that saving will obviously be doubled and the pay back period halved. Few things can actually go wrong with a solar thermal panel - it makes use of the sun's energy to heat a separate coil in the hot water cylinder, and then this heats the rest of the cylinder. The magic of sunspaces Located on the south face of the North Wing are sunspaces which improve the environmental performance of the houses. This is done in three principal ways: first, it acts as a buffer between the inside and out; it uses the warmth of the sun for the purpose of preheating ventilation to the adjacent living spaces and; lastly, by effective creation to the south side of a large draught lobby to the garden. Doors, vents and louvers can be to control these spaces. If correctly used, it will reduce the heating requirement for the houses, and the energy benefits also. Design OF Foundation Ground conditions on this site are very poor, as the subsoil happens to be highly organic material in this damp area and marshy region. The solid foundations had to be laid at least 14m below ground level. Piles were driven down through the damp and marshy ground into the underlying clay. Once ground beams were in situ and in place on top of the piles then the building above the ground could commence. Use of Masonry For the ground floor thermalite blocks were used to build it and these are made out of recycled aggregates. For the support structural loads and achievement of thermal mass 14kN dense blocks were used. Bricks were used to clad the gable and back to first floor although high embodied energy is contained cement mortar. It was used with lime mortar. Lime mortar is not suit for the speed and weight of building with large blocks, because it has lower embodied energy but cures more slowly as a result so cement was used in block walls and lime mortar in reclaimed brick walls. Insulation Installed into the walls of Great bow yard is Warmcell, this material resist fire because it has been treated with organic salts and at a points Rockwool was used in place of warmcel to provide certain level of fire protection between the buildings. For the roof and for the internal walls for soundproofing, semi-rigid form of Rockwool insulation was used for ease of installation. Installed for the floors was Jablite expanded polystyrene. It was used with addition to superinsulation in the timber frame as the floors also have a larger thickness of insulation. SECTION 3 In this section, there is going to comparism between Great Bow Yard in Langport Somerset and a building by university of Westminster. We shall take a look at the following: in the case of our case study above, The ground was poor; the subsoil was highly organic and damp area. The solid foundations had to be laid at least 14m below ground level. For the building by university of Westminster, the ground floor construction was done in a manner in order to achieve a floor U value of 0.28w/m2 k. A floor construction system manufactured by Trent & Jetfloor was used. Precast concrete beams at 635mm separation were laid at the foundation the system polystyrene insulation blocks are fixed in place between these beams. The building is superinsulated far above the requirements of building regulations; electrical appliances are used to generate space heating. Also used to provide conventional radiator based heating and also heat the water is Combi boilers. Sophisticated with special settings for summer and winter, weekdays and weekends are Wood pallet automatic boilers. For the Westminster university building, the heating is provided by a gas fired wet central heating system fed by a stelvad/ideal Turbo 29.1kw condensing balanced flue boiler. Radiations are fitted with thermostatic radiator. The thermal conductivity of the building elements are measured by the U-values. The U-values are for Great Bow Yard is as shown in the table below: Element Building Regs (2004) (Wk/m) Great Bow Yard (average) (Wk/m) Walls 0.35 0.13 Roof 0.2 0.11 Windows 2.0 1.60 Floors 0.25 0.16 Comparing the U-values, it is apparent the building by Westminster University has a higher value in all except for the window. This shows that the building in Brixton London is more solid. Element Building Regs (2004) (Wk/m) Development building in Brixton London walls 0.35 0.19 Roof 0.2 0.12 Windows 2.0 1.2 Floors 0.25 0.28 Solar thermal panels mounted on the south of the building should as a matter of estimation reduce water-heating costs. There are few things that can go wrong with a solar thermal panel - it uses the sun's energy to heat a separate coil in the hot water cylinder, which in turn heats the rest of the cylinder. In the building by Westminster, cold water storage is eliminated from the roof space to avoid penetration into the roof space by the pipe, being replaced by a direct feed mams pressure water system. Moreover, the hot water cylinder is factory sprayed with urethane foam to a thickness 60mm. References Greening Government: Towards More Sustainable Construction: Green Guide for Managers on the Government Estate, Department for Environment, Food & Rural Affairs. retrieved from http://www.defra.gov.uk/sustainable/government/publications/report1999/12.htm http://www.ecoshomes.co.uk/settingthestandard.html http://www.defra.gov.uk/sustainable/government/publications/report1999/12.htm OGC Cover http://www.ogc.gov.uk/documents/AchievingSustainabilityConstructionProcurement.pdf Sustainable Architecture and Building Design. Retrieved from http://arch.hku.hk/research/BEER/sustain.htm Thomas A. Fisher, AIA, November, 1992 UK Govt Sustainable Development - Publications. Retrieved from http://www.defra.gov.uk/sustainable/government/publications/report1999/05.htm Read More