Construction Related Building surveying assessment

Building surveying assessment

Task 1

1. Building construction stages

Walls

The building’s timber-framed walls have been erected compliant with the Australian Standard 1684. High-tech manufacturing devices are utilized to produce prefabricated frames within an off-site industrial unit. These frames are then transported to the construction site in a ready-to-use state with explicit instructions for installation. The timber frames are non-load as well as load bearing, with synthetic erection and construction material to ground slab and sub-floor frames. Frame components include plates, trimmers, studs, blocking, noggings, and lentils.

Figure 1. Wall -timber-frame

External walls utilized a brick veneer, constructed using clay bricks which are produced in strict compliance with AS/NZS 4455:1997, Masonry units and segmental pavers; AS 3700-2001, Masonry structures; and AS/NZS 4456:2003, Masonry units and segmental pavers and flags — methods of test. According to traditional brick-veneer construction rules, the brickwork is largely placed on the edifice’s exterior (Page 1996).

Figure 2. External brick veneer wall

A vapor barrier was constructed out of foam insulation layers on the exterior. MacDonald and Keystone Retaining Wall Systems LLC (2014) recommend the installation of a breathable membrane on the frame’s exterior for condensation-prone climates, for positioning bulk insulation, together with the provision of a 10mm air gap between the foam layer and frame for draining condensation (Walker 2004). The aforementioned insulation was restrained, physically, within stud walls formed from brick veneer. External stud wall wrap offers restraint.

For objects to penetrate through the wall, the insulation needs to be cut neatly around them. The batt ought to be aligned near a given object, followed by being cut at its edge to roughly the object’s center for suiting the required area (Walker 2004). Within the construction being analyzed, cross bracing, water lines, natural gas lines, PVC vents, AC gas lines, bracing adjustment bolts and other non-electrical services have been situated within stud walls, governing batt installation. This includes: batt stoppage at the barrier and its resuming after the barrier, removal of a part of it for limiting contact with the given object, or barrier chasing and cutting into the batt.

For resisting any horizontal racking force, the edifice exerted on the building, the walls are braced permanently. The bracing aims at resisting racking forces that are greater than or equivalent to forces in case of Sydney area. Every internal bracing wall is affixed to — (a) the roof frame or ceiling; (b) exterior wall frame; and (c) the lower storey’s bracing wall floor.

Roof

The building has a timber roof. Its framing was braced appropriately for effectively resisting distorting forces; further, it was effectively fixed together with the use of a prefabricated framing anchor system and recognized nailing patterns. Timber grades utilized within the framing are in line with AS 1684 Timber Framing Code requirements. The building’s roof profile fulfills every requirement stipulated under AS 1562.1:1992 – the code delineating sheet metal roof installation and design specifications. Moreover, the roof fulfills the requisite that it resists concentrated load and external forces, in accordance with tests conducted as stated by AS 4040 (SAI Global, 2011).

Figure 3. Roof framing

Adequate roof bracing has been achieved to restrain the load due to direct wind action, in addition to preventing truss buckling or rotation because of ceiling or roofing material weight. Roof bracing comprises lateral restraints for trussing top chords (or roof battens), web ties, bracing of bottom chords, and diagonal bracing for trussing top chords by utilizing wooden brace.

Figure 4. Corrugated iron sheet roofing

Roofing material is made of corrugated iron sheets. A bent gutter-like sheet has been utilized for covering the roof and fascia board edges. Gutters help collect storm water that gathers on the roof. Gutter installation has been carried out using an appropriate fall for avoiding ponding and facilitating easy flow of water. The storm water gathered via gutters is directed to the earth and ultimately drained using downpipes.

Services and finishing (could include windows/doors, cladding, drainage, electrical installation, etc.)

The finishing of a part of the building’s exterior wall is done using stone cladding, which facilitates the creation of a natural look, besides adding elegance and style to the structure. Such cladding makes use of thin artificially-produced or natural stone layers for lending a magnificent rustic and earthy appearance to the structure. But aluminum cladding makes up the finishing material for the major portion of the exterior wall. This material’s minimal maintenance, superior recyclability, and anti-corrosion facilitate the preservation of its original texture and design for several years continuously, with established lifetime performance (BCA 2015). Galvanization helps safeguard aluminum claddings; it is integrated completely into the used metal for providing all-round protection.

Figure 5. Aluminum external cladding

Additionally, the exterior wall’s clay brick components have a cement and sand finishing which renders them painted. All edifices use plaster for serving two purposes – protection and decoration. This external plaster plays the role of primarily safeguarding the building’s covering structures from external environmental effects (such as the sun, the wind and rainfall), as well as offers sound and thermal protection to its interior. Paint was applied using a brush-and-roll technique. The building’s internal wooden walls have also been painted (Domone and Illston 2010).

Figure 6. Interior finishing

The building under study has aluminum windows and glass vane doors, with the former secured by means of back nailing using stud; exterior windows and doors are nailed across metal brackets for brick veneer.

1. Brief notes on observables

Wall

Roof

Finishing

Observables materials

1. Diagonally, vertically, and horizontally situated timber bars

1. Glass windows and doors with aluminum framing

1. Clay bricks

1. Timber frame

1. Downpipes

1. Gutters

1. Nails

1. Roofing made of corrugated iron sheets

1. Wooden fascia board

1. Door vanes and windows

1. Painting

1. Aluminum cladding

Table 1. Observables in the pictures above

1. Hand drawn, fully labeled sketches

0. A section through the external wall, from the base of the footing to above floor level, and about a meter into the interior of the house

Figure 7. Cross-section sketch of the wall showing brick veneer wall with interior timber-frame (Adopted from MacDonald Keystone Retaining Wall Systems LLC 2014)

0. A section through the wall, with a window

Figure 8. Section of wall with window (adopted from Thorndyke et al. 2016)

0. A section through the upper wall, ceiling and roof to about a meter into the building’s roof space

Figure 9. Section of wall, ceiling, and roof (adopted from Satheeskumar et al. 2015)

Task 2

The building in question utilized aluminum cladding. Weatherboard cladding is an alternative option. The above-mentioned materials have numerous features which will be compared for evaluation purposes under this section.

1. Durability

Whereas aluminum cladding has the properties of lasting durability (estimated life: several decades if adequately taken care of) and superior strength, weatherboard cladding tends to warp, contract, and expand with fluctuation and humidity and temperature levels across seasons. Damaged window seals and soaked wood frames might need to be replaced. Further, weatherboard cladding enjoys only moderate or low durability based on its maintenance and species and maintenance. Grading is done on a scale of 1 to 4; with ‘1’ indicating top-quality cladding and ‘4’ indicating the material is not suitable for being used externally. The gradings commonly vary on account of milling exposures and the presence of heartwood (which is more durable) and sapwood (which tends to rot) (Gleeson et al. 2013). Cladding using aluminum, which is a lightweight and sturdy material apt for outdoor use and not vulnerable to exposure to harsh environmental conditions and water, is thus superior (with regard to durability) to weatherboard cladding.

1. Fire resistance

Normally, aluminum cladding is more fire resistant as compared to weatherboard cladding. Fire tests conducted using the former reveal that when temperature goes beyond its melting point (600-660°C), the metal surface in direct contact with fire melts, though it doesn’t burn. When the test culminates, the aluminum re-solidifies (Peng et al. 2013). Meanwhile, weatherboard cladding has poor fire resistance, except for some hardwood species. Such material typically doesn’t fulfill the necessary non-combustion material types A and B conditions without applying fire retardant treatment. Hence, aluminum cladding is more superior and promotes safe occupant evacuation in the event of fires.

1. Acoustic properties

Owing to its weak acoustic properties, weatherboard cladding is utilized in manufacturing sound protection barriers. All kinds of wood aren’t suitable for making barriers. One may make use of only dried coniferous wood (i.e., fir, pine and spruce). Further, weatherboard cladding’s noise-protection properties are governed by cladding mass (Gleeson et al. 2013; Kissell and Ferry 2002). Meanwhile, aluminum cladding is not suitable for use as a noise barrier owing to its superior acoustic properties.

1. Insulation properties

Aluminum cladding provides no insulation as the metal’s property of high heat conductivity makes it an ineffective insulator. Consequently, the cladding may lead to the loss of considerable energy from cooling or heating. Meanwhile, weatherboard cladding has more superior insulation properties when compared with aluminum owing to wood’s weak thermal conductivity. Specific insulating properties depend on sealing, density and thickness. A building’s thermal properties are governed by the wall system’s thermal resistance (R-value). As weatherboard cladding enjoys a greater R value than aluminum cladding, it is a better insulation material (Brookes and Grech 2013).

1. Sustainability

Cladding of timber weatherboard provides a recyclable carbon credentials resource. Pine weatherboards grown o plantations are a god choice for environmental conservation. This type of timber plantation removes 1.7 tonnes of carbon dioxide from the atmosphere for every tone of wood produced. The wood is a great choice for the ecosystem. On its part, aluminum weatherboard can also be recycled several times without losing any value. The only difference here is that for aluminum to be produced, on requires a high amount of energy. Furthermore, some greenhouse gases are produced when aluminum is being produced (Efthymiou et al. 2010). While both weatherboards are regarded harmful to the environment, aluminum cladding has far more negative effects compared to the cladding of timber weatherboard.

1. Cost

Timber is versatile. Comparatively, it is more expensive to produce timber weatherboard cladding compared to aluminum. Additionally, the maintenance of timber weatherboard is more demanding, hence pushing the cost higher. While aluminum is cheaper, it is more susceptible to damage. The advantage with aluminum cladding is that one only needs to wash it every year. The cost of installing both weatherboard cladding and aluminum is the same. The only variation may arise because of the type of cladding applied (Aluminum Association 2000; Efthymiou et al. 2010).

1. Ease of handling

Aluminum and weatherboard cladding are good because they make it easy to work with. It is important to make sure that timber cladding is properly fastened. The configuration and size of the nail matters a lot. Experts advise that fastening should be done by hand because gun fixing is known to bruise the board surface. It is also important to seal every cut ends after cutting prior to installation. An aerosol end seal primer is recommended. A double coat of oil-based primer –premium may also be used (Barclay 2011). When doing cladding for aluminum, it is important to take into account such aspects as center line, embedded depth and even height. Aluminum cladding requires that you take note of a good number of places.

1. Speed of construction

In the construction process, there is a difference in the time it takes between aluminum cladding and weatherboard cladding; although they are both easy to work with. Owing to its cumbersome nature, weatherboard cladding takes longer to do installation to completion per structure. Timber weatherboard requires many pieces for every selection. Aluminum takes a much shorter time because it comes in large pieces. The balance is struck in the end though. Given the varying need for attending to the details during installation, one finds that the speed will be averagely similar for installing the two.

1. Installation details

Similar guidelines are used in the installation of aluminum cladding and timber weatherboard. The installation principles are also similar for the two types of cladding. The state of the climate may necessitate a change in the dimensions. There is a requirement for approval by a building authority before installing either type of cladding. The existing construction laws will determine the execution procedure. Such aspects as height, location and type are also considered. For instance, the buildings that exceed 8 meters in height need to comply with fire protection and stability requirements (Forsythe 2007). A structural engineer is called upon to provide direction about the fastening distances that are appropriate for the two cladding types.

Hand-drawn sketch of weatherboard cladding

Figure 10. Weatherboard cladding (adopted from Innova 2012)

Task 3

The structure is located in the Parramata area of Sydney. The area is a wind classified location. The site has been determined by making use of the climatology prospecting for wind measurements in a range of locations in the area with prospective points. Mapping for wind resource was also used in the determination. It was established to be a wind classification N3 with wind speeds of 41m/s (Australian Standard 2012). The simplified wind classification requirements were applied to determine the type of wind classification that was necessary. Further descriptions show that the site falls under the category 3, denoted as TC3 and comes with several obstructions that are closely spaced. There are tree and buildings obstructions too, with an average height between 3 and 10 meters. The category of the terrain is critical since it has an import on wind speed and reaches the structure. The terrain determines the speed of wind.

Figure 11. The construction site and the obstructions around it

The site is situated on a moderate slope with a classification of the topography of T0. Small hills can work as objects for aerodynamics; in which case the acceleration of the wind happens over the hill. The intensity of the forgoing will be influenced by the size and shape of such a hill. It will be noticed that the location is under FS; which is a denotation for Full Shielding. The site has at least a couple of rows of housing of permanent obstructions that surround the construction project under consideration. The location is also under heavy vegetation growing at least within 100 meters of the site.

Figure 12. Landscape elevation

Racking force

The building under consideration is 13.5 meters long, 8.5 meters width, with a roof pitch of 260. Wind classification: N3. Te structure is a single-storey construction. The wind force of the structure runs along its length. Therefore, the length raking force is determined. The roof is a skillion and lean on. It is positioned in perpendicular relationship to the direction of the wind. The load of wind on the house was computed using the housing wind loads. From the table given, the wind force of the house in question is found to be 5kN/m. The raking force on the structure is kN= elevation area (m2) x the wind pressure laterally(kPa)

=5kN/mx13.5=67.5 kN

The tables shown, i.e. 8.1 to 8.5 are categorized as AS 1684.2 and AS 1684.3 can be applied to determine what pressures the house experiences for the pair of require wind directions via the following procedure.

1. Selectin of the table with the relevant wind direction was done: the tables were 8.2 and 8.3 for the wind running perpendicular to the ridge and tables 8.4 and 8.5 for the wind running parallel to the ridge.

2. Level of the building was also assigned an appropriate table. There is a need to elevate both the lower and upper ridge for buildings with two storeys. Single upper storeys will use table 8.2 and 8.4. Table 8.2 and 8.4 are relevant to the lower storeys.

3. There was a table selection that was appropriate to the wind classification of the structure in question

4. Selection of the row that corresponded to the house width was done and measured parallel to the wind direction ranging from one external.

5. The column that corresponds to the roof slope was chosen. The current building has several pitches. Therefore, the pitch of the panel that faces the wind was used.

Bracing

Bracing is necessary to hold back the pressure of the wind on the structure made of timber. There is a lateral load from the wind pressure which needs to be transferred to the foundation. The floor and ceiling form a horizontal diaphragm. The force of the wind is transferred through diaphragm of the ceiling to the walls of the bracing which in turn transmit to the structure of the floor (Standards Australia 2011). The engineer made use of AS/NZS 1170.2 and AS 1720.1 to choose and specify the parts with enough strength to carry the load. Wind forces on each of the structural parts were calculated using AS/NZS 1170.2 including the elevation of the roof. ASN/NZS 1170.0 was applied to combine with loads that have self-weight and loads of occupancy among other aspects (Standards Australia 2011).

Nominal bracing of the walls includes walls whose elements are tied by use of nominal fasteners although they come with a bracing capacity that is incidental. The structural bracing of the walls includes walls with elements that are fixed using spacings that are reduced. There are structural details that are specifically meant for the structural wall; at the top and bottom of the wall. There is a higher capacity for the bracing by the walls even if the material is similar to the wall bracing ones. AS 1684.2 and AS1684.3 demand that the structural wall bracing offer 50% of the required bracing capacity, at least (Standards Australia 2010a; 2010b).