The Centre was set out on an open plan with the detainees housed in dormitories and attending schooling and vocational technical training on site during the week. The principle of rehabilitation through the combination of education and physical labour is a doctrine that the centre had adopted throughout its history. Indeed, the initial building phase between 1912 and 1922 relied on the physical labour of the inmates for the construction of the Centre's major buildings, many of which are still in use today.

Accessing Mount Penang.

Access was the first obstacle that needed to be overcome. With all the equipment and stores being bought in by bullock, bricks were ruled out as the main building material, due to the difficulties of transportation and associated costs

From the inception of the project, a building committee was established to oversee the construction and to work through any potential difficulties. As an alternative to bricks, the Committee recommended the use of local hardwood and sandstone for the works, the latter quarried on site.

The building committee architect, Mr James Nangle, also recommended the use of concrete for the buildings, which would reduce cost and overcome the problem of transport. James Nangle had worked as an architect in Sydney since 1891, being employed in the design of residential, commercial and industrial projects. His work with the Department of Public Instruction on the design of portable classrooms made him well qualified to sit on the Building Committee for Mount Penang.

The Minister for Public Instruction approved the plans, with a budget set at £12,000 for the main structures. Work commenced on the first day of July 1912, with the boys providing the labour; another cost-cutting measure.

To begin with, the boys were accommodated in military-style bell tents while they worked on the construction of their own dormitories. The boys were split into work parties under the supervision of tradesmen who could provide assistance and guidance to the boys. The first buildings to be constructed were the ones that were the most essential to the institution:

dormitories,
a dining room,
staff quarters, offices,
a kitchen,
store rooms for supplies and equipment,
and accommodation for the tradesmen and Clerk of Works.

The Minister for Public lnstruction laid the foundation stone of No. 1 Dormitory by December 1912.

By September 1913, No. 1 Dormitory had been completed, as had the Assistant Superintendent's residence and four weatherboard cottages for the married staff members. These cottages still stand along the entrance road to the complex.

In their spare time, mainly on Sundays when no construction work was undertaken, the boys developed a sports ground under Walpole's supervision, which was dedicated in 1912. The ground was developed adjacent to the building site, at the front of the dormitories but at a lower level. To the north of the building site, a team of boys also opened up a mile-long drain using a road plough, and sank a well 12ft deep to tap an underground stream for fresh water!

By 1914, Mount Penang was dealing with all boy delinquents who had been institutionalised in NSW through the Children's Courts.

In 1915, the Superintendent reported that a second dormitory of concrete, a concrete reservoir, a store and office had all been completed. The two dormitories were built on either side of the Household block, with the officers' dwelling behind.
Other works on the site during this period included: the construction of a windmill to pump water from a fresh stream below the escarpment; five galvanised tanks for water storage; a carpentry workshop; a 300 yard trolley line for transporting the sandstone from the quarry to the site; and a plant consisting of a bullock team and wagon, two horses, two spring carts and one dray.

The buildings were all roofed with corrugated iron. Also during this period a permanent dam and concrete reservoir were completed, supplying the site with constant fresh water. Construction work continued at the site until c1922.