WEEK 9
In Detail #2 # 640263 KATHRYN RANDALL-DZERDZ
Re-evaluation
The past week’s course materials and tutorial discussions have led to a broader understanding of the detail investigated in the Week 8 journal (“In Detail #1�). This journal entry aims identify and explain learnt detailing techniques present in the detail provided.
Interrogation of detailing decisions and purpose The assigned detail is a box-gutter above the function room of the new University of Melbourne sports pavilion. It is an area that is expected to be receiving and channelling a lot of moisture, and must protect the internal structure from coming into contact with this water. Therefore, multiple water-proofing methods have been put in place. In order for water penetration to occur, there must be; moisture present, an opening, and a force (Newton 2013). Elimination of any one of these three factors will prevent water from entering a structure. As an area readily exposed to water, a combination of sealing openings and neutralising forces has been used. A. Sealing openings This gap (1) had been identified as a point of possible water penetration, so a joint sealant and backing rod have been employed. An aluminium fascia (2) protects marine ply beneath it on the parapet, and the metal deck roof (3) protects the internal roof structure from water penetration, and promotes run-off. As additional protection, a water-proof (4) membrane covers internal lining, preventing any water from being absorbed. B. Neutralising forces Both the roof and the parapet fall towards the gutter (5), encouraging the water to flow off the building, instead of pooling and potentially damaging either of these surfaces. Drip lines (6) occur on either side of the gutter that direct the water into the guttering system and prevent it from moving, via surface tension, back towards the building. The double-thickness internal wall lining (7) helps improve fire-resistance and reduce sound transmission (Ching 2008b).
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Economic and environmental analysis The intricacy of this detail, and many components that need to interlock, may take more time, and therefore, contribute to higher costs of labour and tailored manufacturing.
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The metals and timber used in the construction of this detail are recyclable. While each require energy to recycle into a new, usable element, this is less than the energy that would be used in the development of a new component. The aluminium used in exposed areas readily forms an aluminium oxide coating that protects it from further corrosion (Jefferson Lab 2013), increasing its working life and reducing the need (and cost) of replacement. There is always embodied energy consumed during all stages of construction (acquisition, transport, and manufacturing), and carbon dioxide produced throughout the process. These are often very difficult to measure however, as it can be difficult to define where and how energy is used, and wastes produced, throughout the entire process. Pros and cons – where are why things go wrong. The complexity of overlaps and techniques used to prevent water penetration would no doubt be successful during average rainfall, however, unusually heavy falls may overcome the rate at which the gutter is drained, and infiltrate through small gaps where overlaps occur. The labyrinth created by the overlap of the guttering system may allow water to enter the building through pressure differentials, as no internal sealants have been used at this point (Newton 2013) – this is a factor that may be unavoidable however, due to the expansion and contraction of metals (Ching 2008a) that requires some to accommodate this movement.
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References
Ching, F. 2008a, “Moisture and Thermal Protection” in Building Construction Illustrated, ed. F. Ching, 4th edn, John Wiley and Sons Incorporated, Hoboken, New Jersey. Ching, F. 2008b, “Finish Work” in Building Construction Illustrated, ed. F. Ching, 4th edn, John Wiley and Sons Incorporated, Hoboken, New Jersey. Jefferson Lab 2013, ‘The element aluminum’, Available: http://education.jlab.org/ itselemental/ele013.html [2013, October 10]. Newton, C. 2013, ‘Detailing for Moisture and Heat transcript’ [e-learning], Constructing Environments, University of Melbourne, Australia.