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When CED are considering windows and doors, it is needed to look at two things. The glazing because we want to have as much sunlight in the house as possible, here it is need to research the U-value and this we want to be as low as possible. The other thing that will be needed to consider is the framing, this will be a part of the u-value, here it is needed to consider which material there will be used when thinking about maintenance etc. The big thing about the windows is the price, double glazed windows are considerably more expensive than single glazed. But the Jones' family are looking to build a sustainable house and one way to be sustainable will be to use as little energy as possible. The double glazed window will definitely help reducing the energy consumption thus making it a more viable alternative.
To understand why double glazing is better than single glazing you need to understand the meaning of the u-value. U - Value represents the heat transfer through a window irrespective of direct sunlight. For example, heat still moves through a closed window at night-time. The U-value is specific to windows and glass and is the inverse of the commonly used R-value, which is used for insulation properties of walls and other building materials. For this reason the lower the U-Value the better the insulation performance. The U-value is important for measuring the heat transfer both in and out of the window. The more heat transfer that the window can resist the better an insulator it is. It can either stop the heat from coming in on a hot summer day or stop the heat escaping on a cold winter evening. (Taken from www.magnetite.com.au)
Taken from: http://www.glassnetwork.com.my/pages/commercial-glass/double-glazing.php
In the summer periods it will be endeavoured to keep the heat out, this can be done by smart passive designs, but also by the glazing in the windows. In the double glazed windows it will also be very smart to put in a film on the glass, this will tone and help against heat getting in. We want the exact opposite in the winter, there we want the heat to come in so we can decrease the heat costs, but also keep the heat inside the building. Below we have put in a table made by a window company (Magnetite), it is comparing their double glazed windows with a single glazed windows. The expression SHGC, also found in the table, means solar heat gain coefficient and is a fraction that is used to indicate how much radiant heat there can travel through a window.
There are a range of issues that we need to consider when thinking about framing for windows and doors. Whether we chose aluminium, timber or PVC, each has their impact on the environment. Where the timber is from a natural source then uses little embodied energy to be produced, but needs maintenance. The PVC and aluminium on the other hand have the highest negative environmental and health impact according to life cycle assessment techniques(Source: ecospecifier.org). Below we have found a table made by Ecospecifier, this will help us to see which of the alternatives is most suitable.
Timber - Non FSC
Timber - FSC, recycled or equivalent
GHG + / Health
GHG / Health
Life-Cycle + (Durability)
Issues of concern/Red Lights?*
Yes - Health
Yes - Biodiversity
Yes - GHG
GHG - Production of greenhouse gases, ozone-depleting chemicals
Life-Cycle Issues - Durability and maintenance
Biodiversity - Destruction or an erosion of habitat and/or biodiversity values, e.g. threatened species or species loss.
Toxics - Toxic and/or persistent and/or bio-accumulative emissions to the environment
Health - Products or emissions during production or use that directly impact on human health
Resources - The use of raw resources, e.g. oil, metal ores.
+ Indicates an overall positive outcome.
- Issues that are of high concern and are a potential eco-design basis for not using the product.
There will definitely be some money to save upfront by choosing to have single glazing in the windows and doors. The family Jones' are seeking a green and sustainable lifestyle and that will the double glazing represent. When thinking about the frame even though it is common to use PVC in Europe it doesn't sound very sustainable and green. The timber framed will be the most green choice, this material will need some maintenance compared to the other alternatives.
According to Maldon Design guidelines, the roof that is approved is pitched or hipped roofs between 15 and 45 degrees for all structures. Below it is shown which types of roofs this is. Both of these solutions would be considerate good, on the pitched roof there will be more room for solar power panels.
When looking for the most recommended roof, fitting this project and site, CED have to consider what type of cladding there will suit best. CED will be looking at some different types of roof that is considerate to be the most suitable for the dwellings.
Hipped roof - Taken from: chestofbooks.com
Pitched roof - Taken from: atlanticexteriorsinc.com
This roof is considerate because CED are looking to recommend the Jones' Family three dwellings that reflects a green living lifestyle, what is more suitable than a green roof.
A green roof is a roof surface, flat or pitched, that is planted partially or completely with vegetation and a growing medium over a waterproof membrane. They may be 'extensive' and have a thin growing medium (up to 200mm deep with 'ground cover' vegetation, or 'intensive' and have a soil 200mm deep or more supporting vegetation up to the size of trees. These roofs are becoming very popular in Europe one of the reasons are when the vegetation is growing it is absorbing the CO2.
Long life span
The weight, it is very heavy (60-250 kg/sq m)
Absorbing a lot of rain water, potential drinking water.
The main issue with this roof is that the construction of roof and walls need to be massive, and the cost for the construction to the roof will be very expensive. And even when building this it is needed to look very long out in the future before it will begin to payoff.
Roof with Tiles
Taken from: http://www.coghlanroofing.com.au/new-roofs.asp
The major contribution a roofing system can make to the environment, is through minimising your energy use and the related carbon emissions or foot print. A roof with tiles can be made more energy efficient by using products like sarking, insulation and ventilation, which we definitely recommend to do. A roof construction with tile are relatively affordable, the tiles are completely recyclable, reusable and is made of materials we have a lot of. Roof tiles have a relative high embodied energy, but at the same time they have a very long life. There are companies near Maldon that reuse tiles and even a company that specialize in using second hand tiles. The company is called 'Roof Tiles Recycled' and is in 24 Bell Street, Preston 3072, then the transport doesn't even have to be a problem because the firm is near.
Easy to install
The cost (compared to the green roof)
Transport - Locale materials
Fits great to most designs
Embodied energy by producing relatively high
Expensive (compared to the rubber or plastic)
Engineered Rubber or Plastic
Engineered rubber or plastic is one of the newest roofing materials in the market. It has a lot of attractive featured such as durability, lightweight and importantly low cost. It is made from reclaimed materials and is available in a variety of styles and colour, so lots of choices for the architect and the Jones Family if they want to use it. It can last for about 30 to 60 years, if well-maintained. It would be easy to install on a roof construction of wood beams and wood boards.
Long life (30-50 years)
Made of reclaimed materials
Found in various of colours
New to market
Isn't found in Australia yet, long transport (US)
It is three good solutions, the greenest solution would definitely be the green roof. But this will be expensive considering the roof itself but also the wall construction that have to bear the roof. The roof tiles would be a good alternative for the longlivety and the low maintenance, this solution would be even greater if using reused tiles. The third alternative is still not that known and is not a material that can be bought locally, so the transport will be very unsustainable.
Recommended Construction Systems
In this section CED lists up which construction systems that are being recommended and why.
CED will recommend the concrete slab, because it will contribute with more properties. The concrete slab will be much better when we are looking at heating and cooling the house, because of the thermal mass. It will make the house a more comfortable place to be, through the use of good thermal mass. If we are looking on the lifecycle of the two solutions the concrete slap would be the best solution because of its long life and the better ability to be recycled. It don't have to contribute with so much embodied energy, if there will be used recycled concrete as written earlier in the analysis and in the later section about building material.
CED have been looking at three different models, a lightweight, a heavyweight and a middleweight. CED will recommend using a mix of the light- and middleweight, using the I-beam as the light construction of the reversed brick veneer, so that the bricks only are there for the thermal mass. The building materials are available on the Australian market, so it will not take much energy to get them transported. The cost of the construction is not much more expensive then a normal wall if any at all. In building materials we will go into which kind of materials there will be good to use and if we can use recycled materials.
Window and doors
CED will recommend using a double glazing Low 'E', because this is the most sustainable choice. It helps with decreasing the energy consumption a lot. It will be more costly to install these windows, but at the same time they save the Jones' family in energy which then results in cost savings. The framing is either out of PVC or the wood framing, the aluminium has poor energy performance and uses a lot of embodied energy to be produced. The PVC would be recommended if the embodied energy wasn't that high, because of the maintenance and it has as good energy performance as the timber. So for framing it is recommended to use timber, this is a natural source and can be extracted locally so the transport don't have to be a issue.
CED have considerate which type of cladding that would be best, to have an idea of which construction there are needed to have under the cladding. CED is recommending the roof tiles for this project, because of the longlivety, require low/no maintenance, easy to install and it is possible to get some second hand roof tiles very near to Maldon. The green roof represent a more green lifestyle, the reason this isn't chosen for the recommendation is because of the price and the weight.
Now when the cladding is recommended, CED can recommend a construction type. CED would recommend the I-beam system that is also recommended to use in the wall. There can be some long span with this solution and this would give a design freedom for the architect and the Jones family. And the solution is good for the environment, because it is made of timber which is considerate an environmental friendly product.
To summarize the construction systems:
Floor : Here we have recommended a concrete slap.
External wall construction: Here we have recommended a reversed brick veneer, with I-beams as the light construction.
Window and doors: Here we have recommended double glazing Low 'E', with framing in timber.
Roof (cladding): We have recommended to use the I-beam system to carry the construction and with roof tiles for the cladding.
We would recommend that there is considerable focus on the air tightness of construction, if we look at Europe and other countries they do a lot to address this. They do it to control the heat and the cold fading away, by making the building air tight there will also be achieved a much better indoor climate.
Building Materials Recommendation
When the construction systems are chosen, it is possible to begin to look at which material there could be recommended to use. Building materials have each their impact on the environment when they are being produced, written in the section about embodied energy. CED will in this section go through the different constructions and recommend some materials. The schedule below is showing how much embodied energy the different building materials consume.
Taken from: http://www.recovery-insulation.co.uk/energy.html
The floor will be made from concrete which have a high embodied energy use. But at the same time there are considering the thermal mass of th product and this is actually why it is chosen. CED would recommend to use the Boral's Envirocrete, this is with 60% replacement of cement and uses 100% recycled aggregates. The Australian Living is the first residential development to use this and the result is, each house is using around 120 cubic metres of Envirocrete which, when compared to standard concrete, saves around 14 tonnes of Greenhouse Gases which is the equivalent of the emissions of an average Australian household.
The reversed brick veneer, CED are recommending have some different materials. There are five materials to make recommendations of.
The outdoor cladding, we would recommend either wood boards or fibre cement boards. The wood boards are definitly the best solution when we are looking on price, embodied energy and natural ressource. But the fibre cement boards do up for its disadvantages, it have a long life, no maintenance, reusable and is produced in a variouse of colors and forms. You can get the fibre cement boards pre-cut and pre-finished, this will minimise the disposal, spills and clean up of the site.
Insulation is already been decided, and this is the cellulose fibre blankets that will be used.
The light construction system will be the I-beam system made out of timber.
Then there are the brick wall, this is only being built for its thermal perfomance. CED would recommend to use recycled bricks, the embodied energy of making new ones is saved and the price for recycled bricks are 20% cheaper than new ones. The recycled bricks can be bought from a local business near Melbourne, called Ecobricks, the factory is about 130 km from the site.
CED would recommend to use recycle plasterboards on the inside of the wall. CED could recommend to use Boral ENVIRO plasterboard, this product have been certified as complying with Good Environmental Choice Australia (GECA). These plasterboards were used in the construction of Mirvac's nine-Star house in Melbourne.
Windows and door material are already recommended in the construction system, this will be double glazing Low 'E' and framing of Timber. The timber has a low embodied energy and will be very good for thermal insulation in the frames.
CED recommend the roof will be constructed with I-beam like in the walls, it will make it a light construction of wood. The insulation in the ceiling as CED have recommended earlier would be cellulose loose fill, made of paper waste. The materials consider for the cladding of the roof is tile, it is recommend because of its thermal performance, long life, recyclable and by using second hand roof tiles there won't be created unnecessary embodied energy.
Looking overall on the building and the interior of the building, CED will recommend using recyclable materials. E.g. it would be recommended using recycled timber for the interior wall constructions and recycled plasterboards, this will both be good considering price and environment. For the flooring in the house CED recommend to use recycled floor, these are fairly cheap and this will be very environmental friendly. This is what we have been having a strong focus on through the analysis of the construction and if the houses are following our recommendations, there will be very little waste from these houses and it will be considerate one very green home.