Tute Week 8 Journal - MSLE First Floor Window Section – Lachlan Hine Interrogation of the detailing decisions: The decision to have a suspended ceiling was likely made for both aesthetic and practical reasons; in the sense that it not only looks good but also allows there to be room for various electrical cords and the like to be tucked away out of sight between the ceiling and the concrete slab. Although the opaque glass used as the spandrel panel was probably more expensive than other options, it increased the appeal of the building and was therefore likely justified because of this. Composition: In this detail a few different materials are evident. Perhaps the most obvious material is concrete, used in the concrete slab between floors, and in the suspended ceiling. Glass is also quite obvious; it is used as the spandrel panel between floors (opaque glass is use according to the annotations), and for the windows above and below the section. The window framing is likely made out of aluminium, as it is a lightweight, relatively cheap form of metal which has goo tensile strength (aluminiumdesign.net, 2013). Vinyl has also been used as a finish on the first floor, and it is likely that the rope-like material holding the suspended ceiling from the concrete slab is steel. Building processes: In this section I assume that they would have built the concrete slab first, which would have likely been poured in situ. This would have been built first as without it the suspended ceiling and the vinyl floor finishing could not have been completed. After the concrete slab was set in place the suspended ceiling would most likely have been built, as it is a large part of the section and would have had to have been done whilst the sides of the building were relatively open. Next to be built is likely to have been the window framing, windows themselves and the spandrel panel, so that the weather would be stopped from getting inside of the building, which would have allowed the inside detailing to be completed. Once the spandrel panel and windows were in place I believe that the next and final step would have been to lay the vinyl floor and complete the P50 Shadowline in the ground floor, as the section would have by now been protected from the elements. Pros and Cons: A positive about this section is the choice in materials. By deciding to make the spandrel panel out of opaque glass they improved the overall exterior aesthetics of the building, whilst the decision to place a suspended ceiling in the ground floor will also pay off, making the inside of the building look very nice indeed. However, as will be mentioned in the next section the choices of materials are not as environmentally friendly as they could possibly be, namely the concrete and glass. This is an overall negative of the detail.
Sustainability and environmental analysis (Carbon footprint, embodied energy and recyclability): As mentioned previously, the main materials used in the construction of this section are concrete and glass (both window glass and opaque glass used as the spandrel panel). Concrete, as a general rule, is not a very environmentally friendly material. It is unable to be recycled (as it is impossible to break it down to its core ingredients of sand, water, cement and aggregate once it has been set), which is a basic requirement of being environmentally sustainable. It also has an unhealthy level of embodied water within it (due to how much water is needed in the concrete-making process) and a relatively large carbon footprint, releasing approximately 400 lbs of CO2 per cubic yard of concrete (Green Ration Book, 2010). Glass is also not a terribly environmentally sustainable material. Due to the production process of glass, it has a large amount of embodied energy, approximately 15 MJ/kg (GreenSpec, 2013). The process of melting the sand and other materials needed to form glass employs the use of large amounts of fossil fuels, as petroleum based materials are generally used to melt the sand. In turn, this elevated the level of CO2 emissions which are made during the manufacturing process. Window glass is also generally unable to be recycled, as it is usually glazed and tinted, thus not allowing it to be melted down and reused. However, some companies specialise in recycling (relatively small amount of) window glass, using it to create fiberglass and glassphalt (Bennett, 2011). Although this form of recycling is not wide-spread, it does help to negate glasses environmental impact to a degree, even though overall it still has a relatively large environmental impact. Economic implications of decisions: The decision to use aluminium window framing most likely saved the builder/developer some money, as aluminium is a relatively cheap kind of material. Concrete is another cheap material which has been utilised; concrete is a relatively cheap mass material which is structurally strong when strengthened with steel rods inside of it. The glass for the windows is a relatively non-negotiable decision; however by choosing to use opaque glass for the spandrel panel the cost of building this section has increased, as opaque glass is a more expensive material to use than other options which were available, such as concrete. Alternatively, the use of opaque glass will likely make the building look more aesthetically pleasing, which may increase the value of the building (thus providing a larger economic benefit to the owner). Where and why things go wrong in this type of detail (eg cracks, leaks, gaps): In this detail of the section between the ground and first floor, encompassing the window, many things can go wrong. If the window framing is not properly fixed to the window pane (or the wall), then leaking may occur as rain may seep into the gap. Alternatively, if the
suspended ceiling is not properly attached during construction then it may cause added stress in the concrete slab, leading to the eventual cracking of the slab. Another possibility is that if the spandrel panel (made of opaque glass) is not securely fixed into the window framing it may become loose over time, thus allowing leaks to occur, or even possibly allowing the whole glass panel to fall out; an undesirable outcome. Bibliography: - aluminiumdesign.net, 2013, Sapa, United Kingdom viewed 23 September 2013, < http://www.aluminiumdesign.net/why-aluminium/properties-of-aluminium/> - Bennet, S 2011, Window Glass Recycling: Difficult but Not Impossible, 1800recycling.com, Oregon, viewed 25 September 2013, <http://1800recycling.com/2011/09/window-glass-recycling-difficult-notimpossible/#.UkJZJYZmim4> - Green Ration Book, 2010, greenrationbook.org.uk, United Kingdom, viewed 25 September 2013, <http://www.greenrationbook.org.uk/resources/footprints-concrete/> - GreenSpec, 2013, United Kingdom viewed 25 September 2013, <http://www.greenspec.co.uk/embodied-energy.php> -