Trinity Church Group includes three nineteenth century buildings: Trinity Hall (1865), the Schoolroom (1872), Trinity Church (1893). These buildings give Trinity Church aesthetic and historical context and influenced the form of later buildings on the eastern perimeter of the site: Trinity House and Guild Rooms (now demolished) and the southern extension of Trinity Arcade (1981). Trinity Hall (1865) is constructed out of handmade bricks laid in a Flemish bond pattern. The building is constructed in a modest rendition of the Victorian Academic style of architecture and is decorated externally with modest tourelles in cement render and has a rendered string course. A large trefoil window faces south. It is a simple building with a timber roof. The interior room dimensions are 16.8m x 10.2m. The interior walls are of white render and there are small stained glass windows with simple coloured panes. The woodwork is of jarrah. The Schoolroom (1872) is to the rear of Trinity Hall and is built of similar brickwork with a timber roof. The structure measures 15.6m by 8.4m with an interior roof height of 4.8m. Trinity Church (1893) is a late example of the Victorian Free Gothic style with Romanesque detailing. It is sited on St George’s Terrace, in front of Trinity Hall and the Schoolroom, behind which is a three storey Commercial Palazzo style building, Trinity Buildings, which faces Hay Street. The latter buildings, which are included in the group, were built in 1926.

Trinity Church follows the fall of the land, with its foundations stepping southwards to St George’s Terrace. Its situation, in front of the earlier Church, which was at the apex of a small hill, respected the earlier building by maintaining a view of the trefoil south window.

An article in the Inquirer and Commercial News on 24 March 1893, describes Trinity Church as: ‘The approach to the building is by a magnificent flight of granites steps, running the whole width. The main entrance is of large and ample proportions and opens into a tiled vestibule, access from which is given to the galleries and body of the Church. The facade is bold and striking, the ends are accentuated and are carried up and terminated by turrets crowned with slate roofs and finials. The central bay is broken by buttresses, which are continued and finished with terminals, between which a gable runs to a height of 50ft crowned with a cross at the apex. The windows in the front are of stained glass, the central rose window being a memorial of the founder of the Church, presented by his grandson, the architect. The ground floor is a rectangle, with splayed corners. The floor is designed especially for congregational worship, having a slope of 2ft in 40, the seating radiating from the eye of the speaker. A gallery runs round three sides, enclosed with an arcade and supported on iron columns. The ceiling is to be of Rocke and Company’s patent stamped zinc, perforated for ventilation. The organ chamber is semi-circular in plan, with semi-dome above, finished with blue ground and gold stars. The Church is ventilated on the Tobin principle and the acoustic properties have been carefully considered. A Minister’s vestry and anteroom are at the rear of the building. There are six exits for the body of the Church and four from the galleries … The seating arrangements are in the most modern and approved style’.

In 1890, two transepts were added to Trinity Hall. These have since been demolished. In 1891, electric lighting was installed in Trinity Church. Over the years, memorial plaques and commemorative stained glass windows have been installed and various items for use in the liturgy, including the lectern, communion table and chairs and baptismal font, have been given by members of the congregation. A number of minor changes to the interior of the Church have been made which reflect changes in liturgical practice and the usage of the Church to service the changing needs of the congregation and community.

In the 1970s, Trinity House was demolished and the area landscaped as a public space. Work was done on Trinity Church to restore the exterior and some of the decorative elements reinstated. Iron bars were put over the lower windows for protection and acoustic panels were installed under the ceiling.

In 1980, Trinity Church was restored under the direction of conservation architect, Ron Bodycoat and, in 1981, pedestrian access from St George’s Terrace to Hay Street was re-established as part of a refurbishment of Trinity Arcade and the Trinity Church. The development of the southern extension of Trinity Arcade, in 1981, included the demolition of the Guild Rooms and the creation of new caretaker’s premises and three levels of arcade on the eastern boundary of the site, with a basement pedestrian link through to the Murray Street level of City Arcade and to a tunnel under St George’s Terrace to Allendale Square. The rear wall of Trinity Buildings was rebuilt to include plate glass windows to provide showroom capacity to the southern shop and a modern staircase, conforming to fire regulations, was installed. An area east of Trinity Hall and the Schoolroom provides pedestrian access to Trinity Buildings. The small courtyard created by the positioning of the new buildings, allows for public space within the shopping arcade thoroughfare and is currently used as a lunchtime seating area for patrons of the former Schoolroom (now a lunch room) and patrons of the arcade. Wooden shutters, which can be unlocked and opened, were attached to the external windows at the lower level. Landscaping and some planting was done to create a garden atmosphere. The new development features speciality shops.

Restoration of Trinity Hall and the Schoolroom at the rear of Trinity Church was undertaken at the same time and the interiors painted in a palette of warm neutral colours. The flooring of both buildings was refurbished and dormer windows installed in the roof of Trinity Hall. In 1993, a replica gold cross, to replace the missing original, was installed as part of the celebrations of the centenary year of the Trinity Church building. Renovations were also made to the 1928 organ, situated at the northern termination of the nave and the organ console with a new triple keyboard was relocated on the west side of the Church. An ongoing program of maintenance and repair of all of the buildings is undertaken in consultation with conservation architect Ron Bodycoat of Duncan Stephen and Mercer.