Construction Process

Lake Wendouree Residence Case Study

stage 1: site preparation AND FOOTING (EXCAVATION, DEMOLITION, FOUNDATION, TRENCH WORK, RETAINMENT AND SERVICE PIPES LAYOUT)

In this stage, the planning has been approved by the Ballarat City council, with building permits appointed to the builder. Demolition is completed by the owner using an external demolition company that removed all the vegetation and previous dwelling from the site. The site is scraped of wild grasses and vegetation that may have grown between the time of demolition and construction. Safety fencing is installed around the site in preparation for construction, with site sheds placed for builders and the construction team. A compacted engineered fill was overlayed onto the topsoil present on site. The surveyor has completed a grid set out for the builders. Trenching was conducted using an excavator for footings to be poured and service connections and pipes to be installed. The concrete arrives on site in a cement truck and is inspected by the building surveyor prior to it being poured. All water and softened materials are removed from the trench excavation site prior to the concrete being poured. The unreinforced blinding concrete is then poured into the trenches using a concrete pourer. The concrete is cured for a minimum of 7 days after it is poured using the approved method and is commenced within two hours of its placement.

stage 2: ground floor slab

Formwork is constructed from timber to create a container in which the concrete slab is poured. It is held in place with star stakes that have yellow caps for safety. 50mm of packing sand has been laid on top of a compacted fill with a polythene membrane laid over the trenches. Steel bars are places as reinforcement on top of the footings. Polystyrene waffle pods are placed on top of the polythene membrane. Steel reinforcement bars are placed on top of the waffle raft pods, 40mm from the surface of the slab. Hydronic pipework is overlaid on the steel reinforcement, with another layer of steel reinforcement bars being placed above the hydronic pipework, at a height of 20mm below the surface of the slab, sandwiching it in. The concrete mix is poured on top of the prepared void formers and reinforcement using a concrete pourer and is smoothed. Cast-in plates are put into the slab, with 4 steel reinforcement anchor bars welded to the underside of the plates. These plates later support the steel members of the conservatory. The reinforced concrete waffle slab is mechanically vibrated to remove air bubbles. The concrete is then cured for a minimum of 7 days and later tested after 28 days. After testing, the formwork is then removed.

stage 3: VERTICAL STRUCTURE ABOVE GROUND (STEELWORK AND TIMBER STUD FRAMING)

Prefabricated hot rolled steel is manufactured in a factory in standardized sizes and brought to the site on a truck. A crane is used to erect the steel columns and beams in accordance with the structural drawings. The galvanized steel cast-in plate is set into the slab and has 4 steel reinforcement rods welded to the underside using a continuous fillet weld. The columns are then brought to the site prefabricated, and suspended by a crane to be welded on-site to the cast-in plate using a full-strength butt weld after the slab is cured. A combination of primed and galvanized steel is used. The majority of the steel structure is constructed using primed steel, which is painted grey and concealed by the rest of the wall and intermediate floor structure, sheltering it from the elements and preventing rust. The columns within the conservatory are galvanized as they are exposed and are identifiable by their shiny silver appearance. These steel members are bolted and welded into place using a combination of different welds like a full-strength butt weld or a continuous fillet weld. The exposed columns within the conservatory are created using a 180mm parallel flange channel column and a 10mm closer plate to create sharp edges to the rectangular member for aesthetic purposes. The other structural concealed steel members which were not visible once construction was completed utilized rectangular hollow sections which had curved edges.

stage four: intermediate structure

Scaffolding is installed for safety when the intermediate floor structure is being constructed. Particleboard and plywood are used to construct the substrate of the second floor, allowing a surface for the floor finishes to be placed on as well as a surface for construction workers to stand on as the walls of the first floor bedrooms were constructed. Timber framing in the form of 120 x 45mm seasoned pine studs and noggins are constructed at 600mm centers. 350mm long reach timber floor trusses are installed at 450mm centers. Timber props are utilized to hold the stud walls in position as they are being fastened and removed once the strap wall bracing is applied. 30 x 0.8mm tensioned galvanized metal straps nailed to the plates with 4/30mm x 28mm galvanized flat-head nails to each end at an angle of 30 to 60 degrees. Plywood sheeting is nailed to the timber frame and is fixed to the studs with 30mm x 2.8mm galvanized flat-head nails, acting as a surface for the zinc wall cladding to be secured later. G clamps are used to fasten the stud frames onto the steel columns until they were structurally sound.

stage five: roof system (roof structure, sheeting, cover and skylight systems)

The timber roof structure is erected, consisting of timber battens and rafters. Once the timber structure is installed and nailed in position, plywood panels are overlaid on the walls and roof frame to create a continuous supporting substrate. Sarking is then placed on top of the plywood to act as a waterproof membrane to prevent moisture from entering the roof cavity. Roof sheets made of folded zinc sheets are used as the cladding on both the walls and the roof. To ensure that no rainwater enters between roof panels, the roof is constructed to have a value above the minimum roof pitch required for zinc cladding. Two insulative layers are found in the roof, blanket insulation at the roof level and bulk insulation above the ceiling. There are box gutters within the roofing system that are made from folded colorbond metal. A plywood substrate is also used to provide structure to the gutters. The skylights are installed in bedrooms 3 and 4 with weather seals to ensure no moisture or drafts are present. Flashing is placed above the window frames to direct rainwater and capping installed on the edges of the roof.

stage six: external walls (CLADDING INCLUDED), WINDOW SYSTEMS, EXTERNAL DOORS

A 19mm marine grade plywood substrate is applied to the timber stud wall structure, with parking attached to the plywood. This marine plywood serves as a surface to apply the standing seam, folded zinc sheet cladding to ensure that it is well supported. The zinc cladding is a folded sheet with 35mm high double lock standing seams. Once the external wall cladding is completed, the windows and external doors are put into place. Glass is brought to the site on vans and put into place using cranes and suction grips. All the glass on-site is Grade A safety laminated or toughened glass. Vertical mullions and operable viridian glass louvers by AGP group were installed. The frames to the bedroom windows were constructed from a Tasmanian Oak head of 292mm and a sill of 44mm. In the conservatory, a 25mm x 25mm concealed glazing channel is set into the joinery with a 140mm x 45mm Tasmanian Oak frame on the interior and is frameless on the exterior. The window frames of the conservatory are made from 76mm thick laminated spotted gum and have a flatscreen installed. Downpipes are fixed to the exterior walls using a VM Zinc Autumn Red Pigmento Plus round downpipes with a 100mm diameter. Matching zinc offset fixing straps hold it in place. The steel frame of the conservatory benchtop is installed, with miter cut corners that are welded together with a full strength butt weld and columns cast into the slab.

stage seven: INTERNAL PARTITIONS, CEILING STRUCTURE, ROUGH-IN SERVICES, WALL LINING

Bulk insulation is padded into the stud walls. Electrical services are threaded through the stud walls and ceiling. Hydronic heating pipes are installed through the walls to be attached to the panels installed in the bedrooms in stage 8. 13mm plasterboard is brought to the site in standardized sheets and is measured and cut into the size required. The ceiling plasterboard is often installed first to reduce potential damages. Stud adhesive is applied approximately every 200-300mm and the plasterboard sheet is placed on top of it. It is screwed to the stud frame with screws and a drill horizontally, with alternating joints. Black block sheets are cut and placed behind the plasterboard to support the plasterboard sheets across their span and are secured with screws and adhesive. The wall plasterboard is installed next, with the same process of stud adhesive and screws to secure it to the timber stud wall. 90 Degree plaster trims are used at the corners of plasterboard walls to strengthen the edge and prevent damage. They are either stapled or nailed in place. Tape is placed over the joints of the plasterboard. A topping compound is spread over the plasterboard joints, edges, and screws. A steel frame is installed in the bedrooms to support the joinery that is built and installed in stage 8. Sanding plates and sanding blocks are used to sand down the plasterboard once the topping compound is dry to achieve a smooth finish.

stage eight: finishing trades, joinery and appliances

Once the plaster walls are sanded down, timber skirtings are installed using adhesive. Once these have been set, often after a 24 hour period, the walls and ceilings are painted with Haymes Low Sheen Acrylic low toxicity paint. The Spotted Gum timber veneer panels are installed to the painted walls on the exterior of the bedroom walls and near the conservatory. The lighting fixtures and electrical outlets are installed. The air conditioning units are connected to the gas and liquid lines in bedrooms three and four with the AC unit being mounted in place. The hydronic heating panels to bedrooms 3 and 4 are also put into place, being mounted to the wall with steel brackets. The joinery installed in the bedrooms consists of a plastic laminate desk and cupboards which were prefabricated and brought on site. They are connected to steel brackets that extend from the wall. The marble benchtop that extends into the conservatory is put into place over the steel frame. The flooring of the conservatory is tiled using Pyranese sandstone and is treated using 2 coats of dry treat satin proof.‘ACO K100’ sloping trench grates with ‘ACO Heel Guard 100’ class A grate was installed in the conservatory. The walls of the benchtop are finished with a 16mm Plastic Laminate with a particleboard substrate and natural