WEEK 09 ACTIVITY: ‘IN DETAIL’ (PART TWO) CASE STUDY BUILDING: OVAL PAVILION 640423
Loose Insulation 35x90mm Timber stud wall
2 layers 13 mm Plasterboard
230mm Precast concrete panel
110x75mm Brick veneer 2mm Metal wall tie
2mm Metal flashing Weep hole 10x5mm Silicon 5mm Frosted plastic sheet 200x900mm PFC steel beam
10mm Mortar bed joint 2mm Metal flashing 2mm Metal wall tie
Interrogation of the detailing decisions and purpose: Insulation - Insulation can assist with weatherproofing and eliminate moisture problems such as condensation. The type of insulation used in construction of Oval Pavilion also has soundproofing quality. Flashing and weep holes - This section of the building uses a cavity wall system, which requires an internal drainage(cavity flashing and weep holes) in order to remove any moisture that penetrates the cladding. Flashing is a thin continious sheet of metal which is installed to prevent the passage of water into a structure from an angle or a joint. Water caught along the flashing is diverted to the weepholes in the masonry facade wall which is mote suceptible to water penetration. The weep holes simply are open purpens in the brickwork. In this detail flashing is extremely important. It prevents water penetration into the lighting strip mounted in the PFC. Sealant(silicon) - Functions to neutralise one of the four predominal forces - air pressure. It ensures that the water droplets are not sucked into the building through the change in air pressure and hence ensures the internal cavity remains dry. Mortar joints - These joints are less water resistant than other joint designs(iron joint for example) as it incorporates ledges where water droplets can accumulate. Thus, to decrease water penetration, the mortar can be further compacted to reduce roughness and inconsistencies of its edges.
Identification of waterproofing elements: Waterproofing membrane is used to divide the brick veneer wall and the lighting strip with the main structure. This prevents water penetration into the building’s footings and advances as if water penetration does occur the exterior elements will be cheaper and easier to change compared to the building’s footings.
Economic implications of decisions: Protecting - Waterproofing elements reduce water ralated issues this building can face, including leakages and rotting. Thus, this allows the maintenance of the building to be cheaper as parts will not have to be regularly replaced. The sealant joint also provides a movement joint for the building to address the issue of minute movement from temperature changes, structural deflection and settlement. This reduces the degree of cracking and costs to repair these cracks. Economies of scale - This section uses easily accessible and available materials and parts, like timber framework or a brick veneer facade which is very popular in Australian building design. Thus this increases the cost effectiveness of the building as labour and
skills are available easily. The brick veneer facade is also a straightforward in construction(wall ties are used to connect the brick wall with timber frame) hence lowering the difficulty of construction and decreasing inaccuracies and labour costs for building.
Sustainability and environmental analysis: The materials used in construction of Oval Pavilion( cocrete, steel and timber) contain fairly high ambodied energy. If the timber is sourced from a plantation or is recycled it will assist in the sustainability of the building. Locally sourced timber and steel will also reduce the carbon footprint of the materials as it would decrease transport energy and cost. Furthermore, if the rainwater collected from cavity flashing system can be recycled and reused within the building, it will dramatically the environmental impact and the economic cost of mainaining the building. Mortar joints also have negative environmental impact as the mortar smeared on the recesses of the bricks are cleaned with a highly acidic solution. Furthermore, mainaining and cleaning the masonry wall can also involve processes which can have a negative environmental or health impact. For example, when using highly acidic or alkaine solutions or organic solvents(which toxic fumes can cause skin burns)
Where and why things go wrong: At the wall system - As the wall cavity is a fairly large unit, water seepages from anywhere along the facade can affect a huge portion of the wall system as water can travel up and along the inner wall through capillary action. Thus, it is important to ensure appropriate water prrofing.
References: Building Diagnostics Group 2013, Building Diagnostics Group, Atlanta, viewed 25th September 2013, < http://www.bdg-usa.com/ masonry-wall-drainage-testing.html> Ching F., 2008, Building Construction Illustrated, 4th edition, John Wiley & Sons Inc., Hoboken, New Jersey. Fitzgerald J, 2010, Home Improvement Pages, Australia, viewed 25th September 2013, < http://www.homeimprovementpages.com. au/article/What_is_a_Fascia_Gutter> Heritage Victoria 2001, Department of Planning and Community Development, Victoria, viewed 25th September 2013, < http:// www.dpcd.vic.gov.au/__data/assets/pdf_file/0020/36830/CleanMasonry.pdf> Krogstad N, 2007, Hanley Wood Media, Washington DC, viewed 25th September 2013, < http://www.masonryconstruction.com/ audiovisual-equipment/raked-mortar-joints.aspx> McGee C., Mosher M., Insulation, Your home technical manual, Commonwealth of Australia, 2010, viewed October 2013, < http:// www.yourhome.gov.au/technical/fs47.html> Wrimco Waterproofing n.d., Wrimco Waterproofing, New South Wales, viewed 25th September 2013, < http://www.wrimcowaterproofing.com.au/index.php?p=1_40>