A02: IN SITU University of Melbourne Bachelor of Environments ENVS10003 Year 1 Semester 2, 2016
NICOLE WEI MIN REN Student ID: 836139
1. Part A - Site Introduction 2. Part B - Progress Report 1 3. Part C - Progress Report 2 4. Part D - Progress Report 3 5. Part E - Foundations, Site Works & In-Ground Services 6. Part F - Footings & Ground Floor Structure 7. Part G - Structural Walls 8. Part H - Upper Floor and Roof Structural Framing 9. Part I - Enclosure Systems 10. Part J - Details & Finishing 11. Part K - Commercial High Rise vs Residential Comparison 12. Part L - Construction Summary & Conclusion
PART A - Site Introduction Site address: 1125 Salt Marsh Crescent, Point Cook Architect/designer: Tribeca Homes Roof: Midland roofing Temporary fence: PINK fence On-site rubbish: Job Site Recyclers (Details regarding other subcontractors was not available)
Temporary fencing Fences of adjacent lots are incredibly close. Space between the house and the fence is also very tight.
Back porch Figure A.1 Architect site signage
Figure A.2 Roofing site signage
Lot 1125 Salt Marsh Cresent is a simple one storey house that is a part of a mass house construction in Point Cook. The construction process begins after a purchase of a plot. Subcontractors are hired by Tribeca Homes to complete certain stages of the construction. The excavation commences the entire construction process and in-ground services are laid, followed by formwork preparation and waffle pod assembly ready for the concrete slab that will be the main base of the home. After almost a month of halted progress as the concrete cures, the main timber structure is assembled on site and quickly goes up with protective sarking. The roof trusses are also put together, possibly on site if there is enough space otherwise is delivered to site. As soon as the trusses are completed, the eave gutters are attached and the roof tiles are placed. Temporary downpipes are also set up so if it rains, the water can be easily drained into storm water drain pipes surrounding the site that were installed at the very beginning.
Garage Rebate (where the driveway will go)
Front porch
Whilst the roof tiles are being assembled, the windows are delivered and slotted into place. This leads to the laying of the exterior brick veneer, during this time the interior can also begin to be put together, including insulation and the plasterboard. The final touches for the place is the interior joinery such as kitchen installations and interior finishes. With multiple stages of the construction going on, the project can save time and ultimately money too.
Sidewalk
Figure A.3 Annotated site plan
PART B - Progress Report 1 Date of visit: 12/08/16 Weather: Cloudy and a little windy Condition of site: Relatively muddy Status: Concrete slab Temporary fencing and plastic sheet barriers
Their position can generally give a hint about the layout of the house 3 different in-ground service pipes Colour coded
Site preliminaries (temporary structures required for workers to work on site) Site analysis Temporary switchboard, where the ďŹ nal electricity panel may go Temporary trash container Concrete slab - where the for construction waste house will be erected on top of Portable toilet
Figure B.1
Excavated dirt Slightly muddy (hence the wood chippings)
Litter around the site (Evidence of workers present)
Yellow waterprooďŹ ng membrane to prevent the concrete from absorbing excess water as it sets
Wood chippings/ bark possibly to prevent slipping and muddy surfaces around the slab (Safety, workability of the site)
Spare reinforcement bars strewn around the site perimeter
indicates reinforced concrete slab created in situ
PART B - Progress Report 1 Current stage: Slab After the underground excavation and installation of in-ground services for the foundation process, workers have poured in situ concrete over a grid of wafe pods which contain reinforcement bars that will help strengthen the slab. No workers nor raw materials waiting to be assembled were seen on site (Figure B.2). Even around the site is relatively empty and void of activity, so it is suspected that the current construction process is at halt as it is neccessary to allow the slab to dry and set. The base is fundamental to the entire structure, no other construction process can take place.
Figure B.2
The site could also be waiting for another company to arrive as different companies will be employed for different aspects of the construction. As there is no more concrete in the vertical structure of the building there is now a transition period between the concrete and timber companies.
Void of activity (workers, vehicles/ machinery)
Figure B.3
Figure B.4
Figure B.5
Bits and pieces can still be found at the site. This handsaw could have been used to trim the PVC pipes down or to saw pieces of spare timber to create the formwork for the slab. This indicates that there is alot of manual labour involved in this part of the process as the concrete has to be smoothened out by a trowel or a hand trowel.
Figure B.6
Construction around the place occurs at a rather isolated pace. Different houses around are at different stages of their process which allows workers to work on multiple projects when stages such as the slab stage requires waiting and not construction.
PART C - Progress Report 2 Date of visit: 26/08/16 Weather: Sunny and windy Condition of site: Dry with occasional muddy spots Status: Installing timber roof trusses; gutter; sarking Roof is in progress, hence the guard rails around the perimeter of the roof for safety requirements
On site delivery of materials
Spare timber planks for the timber structure
Sarking is installed and nailed to the timber frame to secure it in place
Subcontractor installing the eaves gutter, which evidently does not require the roof tiles to be installed ďŹ rst
Timber trusses
Figure C.1 Panorama view of site to show construction progress
Flashing
In ground service pipes a vapour barrier for condensation that occurs on the border of the interior and exterior walls
Steel cross bracing (roof) instead of plywood bracing because of the angle
Openings left in the timber frame and sarking for windows and doors
Wood chippings still surround the edge of the house
Temporary fencing still here
Electricity panel Temporary toilet supplied for health and safety reasons
PART C - Progress Report 2 Completed since last visit: Main timber frame structure, wall sarking, roof trusses Current stage: Roof purlins and eaves gutter installment
Purlins
The main timber frame is essentially the skeleton of the entire project and has to be completed before anything else happens. But whilst the roof trusses are being completed the eaves gutters can begin as they are dependent on the primary truss structure and attached to the fascia, not the secondary purlins. At this stage, several stages of the process can be carried out at the same time. During the site visit, subcontractors are separately working on the eaves gutter and roof purlins. The eaves gutter is a relatively easy task as there is only one worker whilst the roof has two. This stage occurs after the main wall frames are put up, timber roof trusses are manually installed on site with planks of timber delivered to site in standard sizes and then trimmed to correct length with on site tools.
Sarking normally placed between rafter and purlins Fascia Eaves gutter Rafter Nail plate
Top plate Stud
Figure C.2 Site visit #2 selďŹ e
Figure C.3 Section showing the attachment of the eaves gutter to the fascia
Purlins are being installed, but the sarking has not been put on the roof. This could lead to possible problems in the future such as roof leaking or inefďŹ cient heat loss through the roof (Ching, 2014).
A ladder is present to allow easy access to the roof. Machinery using electricity from a generator is required for the nail gun in assembling the roof, whilst hand tools are used for slightly more delicate work attaching the eaves gutter. Tiles and windows are delivered, indicating the next stage of the construction process after the roof and gutter are completed. Figure C.4 Front view of site Materials are stored on site as they are delivered there. Temporary equipment such as the guard rails are stored on trucks which make them easy to transport around the neighbourhood as other houses will need to use them as well.
Figure C.5 On site power generator Hand tools such as screwdrivers and hammers are used to attached the eaves gutter. Additional platforms required for the installation of the eaves gutter.
PART D - Progress Report 3 Date of visit: 20/09/16 Weather: Sunny and slightly windy Condition of site: Extremely dry except for some muddy puddles Status: Brick veneer Exposed LVL timber Solar panel installed to be covered with to provide alternative brick veneer later green energy source
Column supporting the load bearing LVL beam
Half the brick veneer has been installed
Wood chippings are pretty much flat by now because of the heavy foot traffic
Finished roof tiling, supports have been taken down
Sarking
Downpipe Ventilation/ exhaust temporarily put installed, possibly aside so it is out for the kitchen of the way
Bricklayers from the subcontractor hired to complete this specific job
Temporary downpipe leading from gutter into Eaves gutter is fully in ground service installed pipes
Figure D.1 Panorama view of site to show construction progress
Windows have a large gap Platform to allow Stacks of bricks between the bottom sill bricklayers to reach were delivered on Discarded bricks and the brick veneer for higher site to be laid by a lying around the sills to be put in later subcontractor Adjacent plot is muddy at a slanted angle to allow and fenced water to run off easily Temporary fencing Plank on the ground so Temporary toilet possibly faulty workers can easily avoid There will possibly be In ground the large muddy puddles an excavation soon service pipes
PART D - Progress Report 3 Completed since last visit: Eaves gutter and roof tiles, temporary downpipes, solar panel and windows installed, roof insulation, soffit, interior plasterboard and ceiling Current stage: Brick veneer
Brick exterior Figure D.2 Partial section of the house indicating the brick veneer. (Figure to be explained in greater detail in Part I)
For this stage of the construction, as the main structure and roof is completed and the brick exterior is not a structural element, the interior furnishings can begin whilst the brick façade is being built. Majority of the main construction process is completed by now, only leaving the external brick façade and interior to be done. During this visit, there were many subcontracted bricklayers working on the wall, indicating it to be a tough task and possibly time-consuming. However, with several workers working on the same task hopefully it builds efficiency and saves time and therefore money.
Figure D.2 Site visit #3 selfie
It is clear on site that a lot of equipment is needed to complete this task.
Completed roof structure Interior plasterboard is being put up as well. Mortar mixer requires electricity and uses an on site power generator.
Figure D.4 Equipment used for the bricklaying process Buckets, hoses and hand trowels are used to apply the mortar, whilst wheelbarrows are used to transport the mortar. This task is very labour intensive, with a large emphasis on manual labour as it is only making the mortar that uses machinery.
Shovel for shovelling sand/ cement in and out of the mixer Pile of sand for the brick mortar, sand delivered to site.
Figure D.3 Front view of site Temporary down pipe installed as gutters are in place
Puddles, evidence of the water that is used in the brick mortar mix
Stacks of bricks have been delivered on site. All bricks are stored on site as it is inconvienient to store them elsewhere and transport them back and forth daily.
Equipment is stored on caged trucks so they are not stolen after hours, also allows for easy transportation of equipment around the area as other construction sites will be using the same equipment later at the same stage of construction.
Figure D.5 Bricklayers in progress Simple platform made from planks and stands that allow workers to build up higher. Stacks of bricks are also distributed evenly around the site to save time and energy transporting them later.
PART E - Foundations, Site Works & In-Ground Services
In-ground services The placement and clustering of these PVC pipes can easily tell of the layout of the house. Polyvinyl Chloride (PVC) is used mainly for its durablity, oil and chemical resistance and fire-reWood bark tarding properties (“PVC’s Physical Properties - PVC”, n.d.). Different types The number of each coloured pipe on site could also suggest what it represents. For example the large amount of green of gravel pipes around the perimeter of the site and in the house suggests that it is for site drainage. The pink and thinner black Stones pipes are fewer and placed strategically around the place. Soil They could possibly be the gas (pink) and electricity pipes (black). Figure E.1 Electricity
Material Coarse-grained soil contains large rocks, gravel and sand. It is a more stable foundation than fine-grained soil so a simple slab element serves as a sufficient base for this structure (Ching, 2014). Preparatory works The site is dug out and levelled out, during this process to provide a solid base. This makes sure the load of the house is distributed evenly across the surface to prevent any possible cracking or uneven sinking of the soil over time. Freshly turned and loose soil around the perimeter of the site is an indication that it had been excavated. There is no evidence of previous vegetation, the entire local area also seems barren of greenery a possible result of ‘site scraping’. Prior to any construction work, a land surveyor pegs out the boundaries of the foundation with red cord and marks the boundaries of the slab. Trenches are also required in order for the in-ground services such as site draining, gas, electricity lines to run through into the house. After installation, trenches are filled with gravel which is good for drainage. The rest of the site work is unable to continue without the completion of all the underground work as the rest of the structure (the slab, timber frame and house) relies on the safe security of the foundation.
Gas
Figure E.5
Site drainage
Figure E.2
Figure E.3
Below the gravel there should be retaining walls lining the excavated area. Balancing cut and fill: The ‘cut’ excavated area will be ‘fill’ed with gravel before a waterproofing membrane and concrete is put on top. Gravel helps prevent support chairs from sinking into wet ground and helps drain excess water away from the concrete.
Figure E.4
PART F - Footings & Ground Floor Structure Main materials: In situ concrete (poured on site). It is too inconvienient to prefabricate a slab. Steel reinforcement bars/ mesh Chairs/ tophats Polystrene boxes
Concrete slab Reinforcement bars Chairs/ Tophats Polystrene box Figure F.3
Temporary timber formwork WaterprooďŹ ng membrane
Figure F.1
Structural system The base of the structure is a solid slab system. A simple reinforced slab is used because the ground is very stable and there is no need for pad or pile footings. Different types of rebars and meshs as seen lying around site (Figure F.2). These are pre-fab and scraps can be reused in other works. The larger reinforcement mesh (black) is used in the top part of the slab, the rebars (red) is used at the bottom of the slab and the smaller mesh is used around the edges for more reinforcement as load bearing walls are most likely to be positioned there (Figure F.3).
Wafe pod The main construction method of the slab. After the gravel is laid, a waterproof membrane is laid to prevent the concrete from absorbing excess water from the ground. The timber formwork for the slab also acts as a retaining wall as the ground has been excavated and therefore extra support (as in Figure F.1) such as metal braces and anchor points are included. It also controls the depth of the slab and acts as a mould for it to set in. However, with such a large structure reinforcement is needed and hence the use of rebars. Whilst a steel rebar is good in both tension and compression, concrete is poor in tension but good in compression.
Figure F.4 Waterproof membrane
Support chairs are needed to hold the rebars around a third from the bottom because the bottom is where the most bending occurs. (see Figure F.5 whilst Figure F.6 shows a reinforced concrete slab)
Reinforcement bars Figure F.5 Figure F.2
Figure F.6
PART F - Footings & Ground Floor Structure Edge beam Floor slab
Loads
Ground
Slab with load path diagram
Figure F.9 Reaction force Span Spacing Figure F.7
Figure F.8
The slab is one of the most important elements of the entire building because it will have the most load. If it fails, the structural integrity of the house will be compromised greatly. Looking at the structure of the slab, it is clearly not a solid block of concrete. However it is still a solid and sturdy base for the house.
At this stage, there seems to be little opportunities for creating too much material waste as rebars can be reused and excess concrete can be recycled to be reused as aggregate.
This is because the wafe pod is designed to help distribute the load across the beams and down into the widely spread columns. The vertical elements can be so far apart yet carry such big loads because the concrete is thick enough and has rebars to aid it in tension and compression. Essentially a structure with thicker elements can have wider spacings before the maximum load bearing capacity is reached. Large spaces in the slab ultimately helps to save material, time taken to pour it and set; and therefore money too because concrete is a labour dependent material. There can be possible vulnerabilities during this stage. If the rebars are not positioned properly and are too close to the surface this can easily result in unwanted oxidation and therefore a weakened structure.
From the edges of the slab there may be a drop edge beam here (Ashworth, 2013), because the ground is sloping down slightly towards the driveway at the front of the site (Figure F.8).
Even the formwork has been reused several times.However the use of polystrene is not environmentally friendly because it does not get reused/ recycled and stays as a part of the ground oor structure Figure F.10
Reused braces ad timber that is most likely waste from previous constructions. This also keeps costs down as no extra money is being spent on new materials that will be thrown away after construction.
PART G - Structural Walls (load-bearing masonry, timber framing and steel framing) This stage is the most important part of the house. It is the main structure that everything will be connected to. However it is one of the fastest and easiest parts of the entire construction process as the normal material used is timber planks. Other houses have used lightweight aluminium, however majority of the residential in Point Cook use timber. Essentially, this structural system is a skeletal framework that provides sturdy bones for the house. Nothing else can be done until this stage is completed.
An on site saw is used to cut the planks to the right length, making this material easy to work with.
Light weight frames easy to carry singlehandedly. Reduces amount of manual labour required, and speeds up the process.
Workers using nail guns to attach noggings to the studs. Pile of excess timber that can be recycled. (Sustainable material)
Figure G.1 Horizontal construction of ďŹ rst oor timber frame
Figure G.2 Erecting and putting the timber frame walls up within a few hours of beginning
Piles of standard sizes timber planks delivered vand stored on site for convenience.
Double top plate, often used if there is another storey Lintel Nogging Common stud Sill trimmer Diagonal steel bracing Figure G.3 Elevation sketch of timber frame wall
Bottom plate Jack stud Jamb stud
Figure G.4 Site photo of a large window opening and diagonal steel bracing
Top plates, bottom plates and studs make up the basic frame. They help distribute load from the roof or second storey throughout the structure into the ground (Figure G.5). These studs are strengthened the by noggings by allowing greater pressure to be applied from the top without buckling. However, when openings such as doors and windows need to be created load transference needs to be considered. In this situation lintels are used to help transfer load across to the adjacent studs. It requires a speciďŹ c kind if laminated veneer lumber beam (LVL beam). This beam is specially engineering to carry greater loads and is able to span a greater distance than normal timber. LVL beams are highly reliable, durable and cost-effective, as well as a sustainble building material (Gurvich, 2013). Figure G.5 Load path diagram of timber frame structure
PART G - Structural Walls (load-bearing masonry, timber framing and steel framing) As timber is an easy to work with material, the entire frame structure is constructed on site. By horizontally assemblying the frame, a rigid and perpendicular structure is ensured. It is also important to note the spacing and span between the studs. As the distance between is dependant on what load they will be carrying. The closer they are, the stronger the structure is. Despite this, if extremely close studs are unnecessary, it will be a waste of material and money. Figure G.6 Sketch showing span and spacing of studs A key joint in the timber wall structure are the corner posts, which is where two or more walls meet. There are a few variations, however most typically the outside and inside corner posts consists of using small timber blocks that have been cut off as excess to help secure and join the corners together. Figure G.7 shows how a 90 degree corner is created, whilst Figure G.9 shows how perpendicular walls meet.
Figure G.11 Site example of diagonal steel bracing
Figure G.12 Site example of plywood sheet bracing Figure G.7 Sketch example of outside corner post Figure G.8 Site example of outside corner post
Figure G.9 Sketch example of inside corner post Figure G.10 Site example of inside corner post
As previously mentioned, the structure also includes diagonal steel bracing (Figure G.11). Bracing is important and necessary to provide stabilisation to the structure. Diagonal steel bracing is typically used at a 45 degree angle, and prevents a side-to-side motion that results from live load (Carter, 2012). Alternative to the steel bracing, plywood or composite bracing can also be used for additional stability. Unlike diagonal steel bracing which is connected from the bottom corner of a wall to the top plate, one full sheet of plywood brace is place in the corner of the wall.
PART H - Upper Floor And Roof Structural Framing The structure of the upper floor is also that of a skeletal system. It also acts as the backbone of the entire upper structure. However this means that the first floor now has a greater load and must be able to carry it. Alternative methods to distribute this load includes using multiple LVL beams where the first and upper floor meet, or to use a steel universal beam (Figure H.1) Steel beams are a lot more expensive than LVL beams, because they require a whole new subcontractor to manage and install it. Often progress may halt in order to wait for the other subcontractors to come and complete this one task. Steel is also not easy to work with on site. For secure and proper joints, steel should be manufactured and welded off site where it can be more easily regulated. It is also difficult to make amendments to the length of the steel beam if required. Figure H.1 Section of universal beam Beams are horizontal members of the structure that are designed to carry vertical loads using its bending resistance, meaning it has to be good in tension (Ching, 2014). Although steel beams are often used because of a space requirement issue, and a LVL beam that supports as much weight as a standard steel beam will be very deep, steel beams have better tension resistance, hence are often chosen for its durability and ability to save space. Wood joists, that are secondary structures atop the primary beams of the first floor, are essential for the frame construction. As they are also made out of timber they can be trimmed to the necessary length on site.
Figure H.2 Site example of steel beam Figure H.3 Sketch example of beam under tension
Insulation between the floors provides thermal as well as acoustic insulation.
Series of LVL beams to support a balcony. Nail plates are used to connect the members. Temporary support beams in place whilst construction is still going on to ensure full safety of the structure. Plywood bracing used here because there is a cantilever on the upper floor, meaning greater unstability and therefore needs more reinforcement.
According to Ching (2014), the spacing between joists can be 305, 405, 610mm apart depending on the span and load it is supposed to bear, also taking into account the type of flooring to be installed. Figure H.4 Sketch example of wood joists spacing
Figure H.5 Upper floor balcony
PART H - Upper Floor And Roof Structural Framing
Figure H.11 Section of a C purlin Purlins
The roof structure is assembled separately to the main timber frame. It may be made off site or in situ if there is enough space. The roof utilises a system of trusses as trusses are based on the sturdiness and rigidity of a triangle. It is therefore able to withstand great pressure in tension and compression (Ching, 2014).
Sarking normally placed between rafter and purlins Fascia Eaves gutter
Load
Top plate Rafter
Reaction forces Figure H.6 Sketch showing how load is evenly distributed through a truss Diagonal steel bracing used for the roof trusses. Plywood bracing would be too much, as a truss is already quite strong itself.
Nail plate
Stud
Figure H.8 Section showing roof structure The type of rooďŹ ng is important to the internal structure of the roof. In a regular timber frame structure, sarking (shown in red in Figure H.8) is normally installed after the rafters are put in. The purlins then go on top so the tiles can easily be placed. The sarking ensures that during storms or when it rains, any possible leakage will be able to drain down to the eaves gutter protecting the inside of Figure H.9 the house from any damage (Ching, 2014). Site example of roof sarking Steel purlins (Figure H.11) would normally be used for metal sheet roofs. However in this case, the sarking would be placed on top of the purlins instead of under (Figure H.10).
Figure H.7 Section showing incomplete structure of the roof Despite the sturdiness of trusses they also require bracing, as even during construction they may easily collapse with a strong wind.
Figure H.10 Site example of steel purlins with sarking
PART I - Enclosure Systems (walls & roof) After the main timber structure is complete, the brick veneer/ enclosure systems are completed next. The timber frame is essential to the exterior as it provides support for both the roof and the cladding materials. This is the structure to which these elements of the house will be tied and secured to. Despite the timber framework being the main structure, the building envelope is much more important as it is what protects the entire house from the outside environment. It moderates the interior climate essentially ďŹ ltering out light and the cold to create a habitable space for the occupants. Fibreglass insulation
Plasterboard
Brick veneer Brick tie Brick mortar Sarking INT
EXT Flashing
Figure I. 2 Site example of a movement joint As the weather changes from winter to summer or vice versa, the bricks expand and contract. This darkened gap is a movement joint (Figure I.2) that allow the bricks some space to expand due to either temperature or moisture without damaging themselves (Ching, 2014). In Figure I.3, the above image shows a widened gap and the below image shows the gap has decreased as a result of the bricks expanding.
Reinforced concrete slab Figure I. 4 Site example of a brick tie
Figure I. 1 Section of wall Timber stud
Figure I. 3 Sketch showing how the movement joint works Weep holes are also essential to the maintainence of a brick facade. It allows moisture to escape and prevents it from damaging the interior or the brick itself. Moisture forms when the exterior is colder than the interior, and so the air in between the gap of the timber frame and brick condense. Droplets of water formed on the sarking will then drip down and out of the ashing. This system ensure that the structure will last a long time.
Bottom plate
Brick veneer is cheaper than a double brick wall because it is quicker and uses less material. It is becoming a more common form of building a house. It also provides better thermal and sound insulation with a cavity of 50mm between the timber frame and brick veneer. The brick is laid on site, meaning materials only need to be delivered, saving time and money than to if whole brick walls were transportated.
Figure I. 5 Site example of weep holes
PART I - Enclosure Systems (walls & roof) The roof is also an imporant part of the building’s envelope. It keeps out the sun, rain and cold as well. It is therefore worthy to ensure that the roof is done properly, so that the entire structure of the house will be protected from potential damage that the weather could bring. Here the eaves gutter is attached, so rainwater flows smoothly down and into the gutter, down the downpipe and into the sotorm water drainage that has been put in place since the site excavation. An eaves gutter is used here because it is less expensive to maintain. For example, if there were leaks or problems with a concealed downpipe carrying rainwater away, it would be more expensive to repair it.
Figure I. 10 Site example of a roof without sarking
Figure I. 6 Site example of an eaves gutter installation
Figure I. 9 Worker blowing the roof with a leaf blower. This could possibly be to get rid of all the unwanted rubbish such as zip ties or pieces of broken tiles.
The roofs in Point Cook are all generally similar in style. They have the classic pitched roofs with dark tiles (Figure I.7). However, there are some other types of roofing such as metal sheeting (Figure I.8) which takes up much less time to install. Often in new neighbourhoods, aesthetics are important and so many prefer the traditional tiles to the metal roof although it takes more time for maintenance and to place it during construction.
Figure I. 7 Site example of dark tiles
Figure I. 8 Site example of metal sheeting
As seen in Figure I.10, some houses do not have sarking below their metal sheeting or tiles. This may lead to future roof problems such leaking when it rains. This could also mean that the house may not be thoroughly efficient in their energy efficiency, because although sarking is not mainly used for insulation, it’s reflective backing does help reflect heat back to an extent.
Sarking Purlins Roof tiles Nail plate Fascia Eaves gutter
During this time, because the gutter is complete, temporary downpipes are installed. It is temporary because the final downpipe of the house can only be installed when the brick veneer is complete as it will be nailed and attached to it.
Figure I. 11 Sketch section example of a completed roof
PART J - Details & Finishing The details of the construction are incredibly important for the durability and safety of the house. Extra measures need to be taken to ensure that elements of the house are properly put together and preserved.
Figure J.1 Site example of timber frame and concrete slab joint To connect secure the timber frame to the concrete slab, holes have been drilled into the slab to make it easier to bolt the timber structure to it. Contractors need to ensure that the nails used to bolt the timber frame to the concrete slab is galavanised so that it prevents corrosion and the timber will not rot quickly (Carter, 2012).
Figure J.3 and Figure J.4 Site example of lifting the timber column up off the ground External elements also have to be extremely well taken care of to prevent deterioration, such as columns that sit out side of the brick veneer structure. Although these columns will also be wrapped in brick veneer, they are not protected by sarking or ashing and so they have been lifted up by metal caps or poles to keep moisture from the ground away from the timber. They are different methods because of the weight that each of them carry. Figure J.3 is only support the meeting point of two LVL beams that create a cantilever for the front porch of the house whilst Figure J.4 is supporting an upper oor balcony that is made out of a series of LVL beams (see Part H).
Figure J.2 Sketch example of timber and concrete joint section
Figure J.5 and Figure J.6 Site example of nail plate; example of steel and timber beam joint As timber is the main material used in construction. It has been joint with multiple different unlike materials. Aside from timber itself (Figure J.5), it has been joined with concrete (Figure J.1) and a steel beam (Figure J.6). Throughout the construction, timber studs and noggings have mainly been joined using a nail gun, but for LVL beams and the roof trusses they have been joined by nail plates, which are essentially steel plates lined with many nails so that the joint is fully secure. Joining timber and steel, like the concrete uses a nut and bolt, however it is done several times to ensure security.
PART J - Details & Finishing The windows and doors are one of the last elements of the enclosure system of the house. Windows and doors are one of the main sources of heat loss within the house, aside from the roof, therefore their installation has too beproperly done or else the outside environment can easily penetrate the house and prevents the building envelope from doing its job, which is maintaining and protecting the interior space. Figure J.8 Site example of brick veneer missing a sill and window Figure J.9 Site example of installed window Around the windows are rubber sealant to trap air and to prevent heat loss. This save money in the long ruan as not as much energy would be needed to heat the house. Figure J.10 Sketch example of window sill and flashing
Soffit Exposed LVL beam that will be covered up with brick veneeer in the end
Figure J.7 Site example of soffit and interior ceiling Interior ceiling
The exterior ceiling at the back porch is a soffit. It is on the roof’s underside and like the interior ceiling, conceals the structures discussed previously. However, it is different to the interior ceiling because it is made out of weather-proof material and normally it is made out of cement sheet (Ching, 2014). It is simply nailed to the underside of the trusses and will be painted over as a final touch to add to the aesthetic appeal of the house.
These are temporary timber beams to hold the newly laid brick facade in place. These are possibly excess planks left around site.
Plasterboard has already been put in place. This is to keep out unwanted visitors from entering the house. This also suggests that the interior furnishings are beginning to take place.
Although the rest of the brick facade is completed, the bottom sill is still not. This could be because the bricklayers have to wait for the windows to be installed first before the sill and flashing can be put in its proper place, like in Figure J.11. The slanted sill allows water to run off as well as the hidden flashing to let out any unwanted moisture (Figure J.10). Working with multiple subcontractors can be difficult, as seen here. Construction progress cannot be continued until other complete their jobs.
Figure J.11 Site example of window sill
PART K - Commercial High Rise v Residental Comparison Address: Banksia Apartments, 429 Docklands Drive, Docklands Builder: Hickory Architect: McBride Charles Ryan Developer: MAB Corporation Building Type: High-rise (17 floors) Number of Dwellings: 118 Site Area: 8, 549.00 square meters Status: (3 part) Excavation, Garden Slab, First level pour, Basement complete (“Banksia NewQuay”, 2015)
Address: Lot 1125 Salt Marsh Crescent, Point Cook Builder: N/A Architect: Tribeca Homes Developer: N/A Building Type: Single-storey Number of Dwellings: 1 Site Area: approx. 150 square meters Status: Completing brick veneer Figure K.2 Lot 1125 Salt Marsh Crescent
Figure K.1 Rendered image of Banksia apartments, (MAB, 2015).
Reinforced concrete slab
Both used subcontractors for the jobs, except Hickory provided some formworkers. Hickory also had a greater range of subcontractors including post-tension concrete, steel fixers, excavators and electricians.
Excavation
Figure K.5 Concrete trucks waiting at Banskia
Figure K.6 Cables sticking out, for post tensioning
The reinforced concrete was produced at a much larger scale (Figure K.5). There were several trucks of concrete and the first thing on site was the crane base; and because it holds a different weight to the basement, a slab was created just for it and it was also put lower than basement. Unlike the waffle pod construction, Banksia’s concrete slabs utilises post-tension, which involves pouring the slab and putting the steel under tension. This allows the slabe to span a greater distance without the need for columns. Cables sticking out of the slab (Figure K.6) would be pulled on by machines like then workers in Figure K.7.
Figure K.3 Excavator at Banksia site
Figure K.4 Excavator at Point Cook
Similar to the residental homes, an excavator is used to dig up the ground so that in-ground services can be laid. It is however, an excavator of a much bigger scale and there were multiple of them not such the one.
Figure K.7 Workers using the machine to put steel under stension
PART K - Commercial High Rise v Residental Comparison
Figure K.8 Banksia basement, black painted flashing
Banksia also utilises pre-fabricated concrete, unlike in Point Cook where the concrete was only in situ. The basement was pre-fabricated panels that were delivered to the site. This was because of a time constraint, and it would take too long to wait for the concrete to cure as the basement had to be done before other stages can start. The basement is also coated in a more sophisticated form of flashing, a sort of black paint.
Figure K.10 Banksia property boundary
Much like Lot 1125, where there was a rebate in the slab to indicate where the brick veneer goes, there is a set down in the concrete slab that marks the interior and exterior of the property boundary.
Modular construction technique Figure K.9 Banksia building core
Figure K.12 Pre-welded mesh for the reinforced garden slab
Figure K.11 Workers on the garden slab
The core of the building is created first, using a steel shaft. The individual slabs of the building are independent as long as the core is complete. The core is usually kept 4 or 5 floor ahead of the floor slabs, so the progress can be continuous and there is no need to wait for the core to cure before creating the floor slab.
Banksia also uses a reinforced concrete slabs. The concrete is vacuumed out onto the site and hand trowelled by workers. They also have machinery to vibrate the concrete as it pours. However, this slab is a garden slab and soil will be covering it so it is only quickly trowelled and not finished concrete. There are also no in ground services pipes so the slab has no penetrations. It is an independent slab to the previously poured slabs and so it allows more movement. Grout is poured in between the slabs to secure it eventually.
The garden slab also uses metal deck and pre-welded mesh to prevent cracking because it is a garden, instead of waffle pod construction.
PART L - Construction Summary & Conclusion Since the last site visit, the brick veneer façade is almost complete and the installation of the interior plasterboard can be seen. After it has been done, installing proper downpipes and external doors will be some of the final touches to the building. For future work, it would mostly be the interior that needs to be finished before the cleaning up and decorating, as shown in a basic construction schedule below.
E
Completed Current stage To be completed (Future works)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
1-5
6 - 10
11 - 15
16 - 20
21 - 25
26 - 30
31 - 35
36 - 40
41 - 45
46 - 50
51 - 55
56 - 60
61 - 65
66 - 70
Excavation & Inground services
F Pouring slab G First floor framing Roof structure H Install eaves gutter Roof tiles I
Install windows Brick veneer façade Install interior insulation & plasterboard Install joinery
J Interior finishes Clean up Figure L.1 Basic construction schedule of Lot 1125 Salt Marsh Crescent
REFERENCES Ashworth, B. (2013). Drop Edge Beam. Anewhouse.com.au. Retrieved from https://anewhouse.com.au/2013/07/drop-edge-beams/ Banksia NewQuay. (2015). Urban Melbourne. Retrieved from https://urban.melbourne/projects/docklands/banksia-newquay-429-docklands-drive-docklands Carter, T. (2012). Diagonal Brace Tips | Ask the Builder. Askthebuilder.com. Retrieved from http://www.askthebuilder.com/diagonal-brace-tips/ Ching, F. (2014). Building construction illustrated (5th ed.). Hoboken, New Jersey: John Wiley & Sons. (Ching, 2014) Gurvich, D. (2013). LVL timber. Woodsolutions.com.au. Retrieved from http://www.woodsolutions.com.au/Wood-Product-Categories/Laminated-Veneer-Lumber-LVL PVC’s Physical Properties - PVC. Pvc.org. Retrieved from http://www.pvc.org/en/p/pvcs-physical-properties