Revitalisation of Old Tai Po Police Station into a Green Hub for Sustainable Living

從舊大埔警署到綠匯學苑: 實現永續生活

Billy Tam 譚漢華

綠匯學苑的活化項目在保育舊大埔警署的同時，亦保留了原址的古樹及具重要生態價值的鷺鳥林，是一個綜合建築、歷史與自然，並展現了可持續性的活化範例。本文以活化保育上的軟硬件作為主軸，討論透過建築師和客戶之間的相互配合，讓新功能與歷史建築及周邊環境得以融合，從而成功實踐可持續發展理念。

The Green Hub, an adaptive re-use of the historically significant Old Tai Po Police Station (OTPPS), serves as a demonstration of sustainable living. Its architecture, heritage and nature were all developed through collaboration with the community. It is also a centre that develops, teaches and promotes affordable and meaningful strategies for low-carbon and sustainable living. 

From the start, the Green Hub aimed at handling conservation in ways that re-used the building’s architecture without overlooking its layers of history and memory. The scheme’s success demonstrates how integrating software and hardware can play a key role in an adaptive re-use. For this project, the key elements were:

• Input – the client’s decisions on the functions that re-use would allow.

• Output – the architect’s inspiration and understanding of the brief.

• Hardware – Old Tai Po Police Station.

• Heritage – the building’s history as the first English-style government building.

• Local ecological – the site is home to the Tai Po Market Egretry and many old and valuable trees.

From the start, the client, Kadoorie Farm Botanic Garden Corporation, wanted to treasure the historical values of the Old Tai Po Police Station while transforming it into an inspiring education centre promoting low-carbon living and a sustainable future. This meant conserving the historic, architectural and ecological values of the property while extending its focus to a wider appreciation of Hong Kong’s ecological and cultural heritage resources so as to continue to serve the community under a new mission.

The building’s original spatial layout had to be highly respected during the design process. Instead of superimposing new usages onto the building and attempting a large-scale reconstruction, the project team carefully examined the existing room layout and designed a new programme that could be incorporated with only minimal changes to the building’s original layout.

The project team also had to retain and protect the adjacent Tai Po Market Egretry and its old and valuable trees along with most of the trees within the site, and where possible had to restore the original building structure and architectural elements. For instance, the existing verandah and louvre windows were restored to preserve their colonial appearance and historical value. Recycled and sustainable materials were used to minimis construction waste arising from demolition and alterations.

In the building’s central courtyard now stands an ‘Enchanted Garden’, which has significantly enriched wildlife habitat. The garden also serves as a base for organic resources and horticultural waste. A greywater recycling system has been installed to show how water management processes work. Together with the its education programme, the Green Hub is now a centre that can develop, teach and promote affordable and meaningful strategies for low-carbon and sustainable living.

Conservation principles
To help preserve the Green Hub’s Grade 1 historic building status, conservation principles were drawn up at the early design to guide the project team in its use of appropriate treatments and levels of intervention for character-defining elements and building fabrics. These were:

a) Respect changes.

b) Retain authenticity and integrity.

c) Minimum intervention.

d) Repair rather than replace.

e) Reversibility.

f) Integrate the new and the old.

One of the major difficulties that conservation projects encounter is compliance with ever-changing building ordinances and regulations. All buildings have to be constructed in compliance with statutory requirements to ensure they are structurally stable and safe for public use. Hong Kong has no particular conservation- or heritage-related regulations providing guidelines for conservation or revitalization projects. The adaptive reuse plan for Old Tai Po Police Station was no exception: it had to comply with the current statutory requirements.

Architect and project teams need to look for solutions that restore a building to its original appearance while meeting their clients’ wishes and needs. Most buildings which become conservation projects in Hong Kong were built more than 50 years ago when most building regulations had yet to be formulated. Having to apply current statutory requirements makes handling conservation projects challenging. The design potential of these projects is often hindered by these requirements. As for Green Hub, there are also limitation and restriction encountered during its restoration which will be explained breifly in the upcoming parapgraph.

Unique features
The Green Hub project also had its own challenges arising from its own unique features. Among the most noteworthy of these was how the timber roof with double pan tiles was handled. To restore the beauty of the original Chinese-style timber roof, a creative solution had to be found for the layering of the double pan and roll roof tiles, a roofing style commonly found in colonial buildings in Hong Kong. The original tile design was followed with only slight modifications in a new arrangement that complied with the ‘Code of Practice on Wind Effects in Hong Kong 2004’. Instead of using structural steel clad with timber, a modern update to the traditional design was carried out by adding concealed steel ties connecting the two layers of tiles and the timber structure underneath. All timber members and roof tiles were crafted to form a structural system that satisfied the requirements of the Buildings Department.

The Old Tai Po Police Station also made a major contribution to the advancement of local conservation practice by helping to establish a rigorous set of submission/approval requirements for projects that involve substantial reroofing of a building using timber. The OTPPS project was the first in Hong Kong to receive approval from the Buildings Department for the use of timber as structural members to restore the roof of an old building, making it a breakthrough project.

Parts of the timber roof structure in the police station’s Main Building had over the years been replaced by steel purlins. These had gradually rusted because of water leakage through the roof tiles. Previously in situations like this, structural steel clad with timber would have been used to restore the roof. But the Old Tai Po Police Station has demonstrated how local conservation using timber roof structures can be achieved.

This whole timber roof restoration exercise was thoroughly and rigorously carried out, and the resulting timber roof structure complies with the current wind code and meets all other statutory requirements. This highlight of the project was the fruit of a multi-phase collaboration between the project’s structural engineers, its heritage consultant and the Heritage Unit in the Buildings Department.

Broader implications
The successful restoration of roof members at Old Tai Po Police Station using timber has now set a local precedent and benchmark for future projects, without doubt advancing local heritage conservation practice. The success of the Green Hub comes not only from the efforts made by the client, operator and consultant team, but also from the government departments that played an important role in the realisation of the project. These departments could be more open-minded in relaxing building ordinances and regulations to help maximise the design potential of future revitalisation schemes. This would help provide a second life for notable pieces of architecture and so open the way for greater public appreciation and enjoyment of them.

Billy Tam is Director of Thomas Chow Architects.
譚漢華是周德年建築設計有限公司的董事。