THE PATERSON CENTRE
Knox Grammar School, Wahroonga, Sydney
Architects: Bligh Voller Nield
Project Architect: Philip Walker
Builder: St Hilliers Constructions
Project Manager: TWCA
Bricklayer: Macarthur Bricklaying
Brief and design intent
Most of the school's buildings are brick. This material and the manner in which it has been used as face brick with stepped gables was favoured by the school for this building. This was supported by Kuringai Council which set height limits and suggested that the new building should match the existing buildings.
After consultation with an architectural heritage consultant, the design was developed with brick detailing that is contemporary, but reflecting that of the older buildings. Opportunity was taken to manipulate the brickwork three dimensionally creating deep reveals and large sloping sills.
The building is a conventional reinforced concrete frame clad with non-loadbearing brickwork and contains classrooms, computing laboratories, and a lecture theatre with a large foyer. A typical plan with classrooms is shown on the Level 3 Floor Plan.
All external walls are face brickwork, as are the internal walls of the auditorium and classrooms, again following the example of the older buildings with their proven record of lower maintenance. Some walls between classrooms are steel stud and plasterboard for greater flexibility and to reduce structural loads. The pitched roofs are terra-cotta tile to match the existing roof and the flat roofs are copper to maximise durability.
Brick paving is used extensively on internal floors and stairs.The partly below ground auditorium is air conditioned and the classrooms adjacent to the noisy Pacific Highway have double glazed windows and mechanical ventilation. The rest of the building is naturally ventilated.
The architects were commissioned to design and document the building and carry out design audits during construction. Average industry conditions prevailed in 1996-7 and St Hilliers' $3.8 million competitive lump sum tender was chosen from six builders. The project manager, TWCA., administered the contract. No significant problems occurred during construction.
The architects were shown samples of the work of the preferred bricklayer, Macarthur Bricklaying. A sample panel was built, but one of the older buildings was also used as a reference. A high standard of bricklaying was maintained throughout the job, due largely to the efforts of the foreman bricklayer and the clear pride in the bricklayers' work.
The external and internal bricks are Bowral Browns with cream bricks internally above 1450 mm, laid in yellow sand mortar. Enough site area was available to allow for on-site mixing.
To achieve and maintain good quality, the brickwork was extensively detailed and the tapered bricks in the pointed arches on the western facade (see drawing) were one of the few purpose made specials needed.
Steel shelf angles and concealed reinforced concrete toes were used to support the brickwork and sliding ties connected it to concrete columns.
The wish for deep reveals made it necessary to develop details of supports for external sloping brick sills and internal sills.
The sloping brickwork on the western elevation is supported on an extended concrete beam and concrete upstand. The sloping brickwork is supported on a steel angle bolted to the concrete, with a separate shelf angle supporting the header course.
A multilayered waterproof membrane is needed to waterproof this assembly. Another steel angle supports the inner brick sill.
(See drawings: Wall section 1 on Western Facade Arched Gables drawing, and Detail 1).
Details 2, 3, and 4 show, for several windows, the extensive use of steel angles spanning between attached piers and fixed to concrete to support brickwork. All these details show the application of well understood principles of support and flashing, but also show the need to detail each particular situation.