Conservation Architecture

St Paul's is currently having a Conservation Architecture Plan prepared by Mr. Ian Bowman.

The following was an address by Jackie Gillies - Conservation Architect, Queenstown
St Paul's Cathedral, Dunedin - 8th March 2006

The Cathedral as Part of Creation

Although there are a few conservation architects in the North Island I am one of only a few in the South. As a conservation architect, I have full architectural training combined with a passion for and specialist knowledge of historic buildings. I did my professional training in the United Kingdom and my postgraduate qualifications at York University completing a Masters in the conservation of historic buildings. This course focused on the practical and philosophical conservation of historic buildings including both the technical aspects of the repair of buildings as well as the philosophical issues behind the decisions as to why some things are repaired while others are not.

When we consider the Cathedral, we need to look at it holistically as a building, its history, its future use and all the issues involved. The vehicle through which all these things are considered is the conservation plan which should be both informative and practical. In preparing a conservation plan we need to work backwards from what we want in the future to the original history of the building.

In section 1, the report covers the history of the building; who built it, what it was used for, etc. Historians play an important part in the development of a conservation plan with importance given to oral history gathered by the present owners. In section 2, there is a detailed description of the building; its materials and construction. From this research, it is possible in section 3 to identify the significance of the building. Sometimes this significance is obvious and sometimes it is not. Different parts of a building would be described and might be assigned different levels of significance, (a hierarchy), but, always, the reasons for this significance is identified and described.

In section 4, policies are outlined to ensure that that significance is conserved. These may range from the general, that all conservation work should comply with the NZ ICOMOS Charter for the Conservation of Cultural Heritage, through to detailed policies regarding the conservation of one small element.. In section 5, emphasis turns to future actions, what the building owner wants to do with the building, what future additions may be needed, what funding issues are involved and where funding may come from, the building specifications are detailed and the maintenance schedule drawn up in five yearly and ten yearly cycles. As an aside, in the United Kingdom the Church of England carries out five yearly inspections of all Church property, a Warrant of Fitness, if you like. These are paid for the Church of England while each church is responsible for the cost of implementing the work.

Conservation plans may be written for historic buildings like the cathedral but they may also be written for much smaller places or even items of furniture. For example, a conservation plan was written to Janet Frame's writing desk. The report detailed the significance of each mark that Janet added to the desk as well as detailing the considerable use of the desk before her time and explaining why the people she entrusted it to while she was overseas, cut the desk in half and joined it back together again. This might have been seen as a gross disfigurement of the desk, but it is part of its story. So you can see that only when we fully understand the history of a place or an item that it becomes clear how we should care for it in the future. Cathedral issues that could possibly be covered in a conservation report may include:

If we look at the nave of St Paul's today we can imagine what a cathedral such as York Minster may have looked like soon after its completion in the mediaeval period with its magnificent stone columns and soaring arches. (However, there are some strong indications that during the mediaeval period the interior of these cathedrals were richly painted and this was only removed during the Victorian period.)

Notwithstanding my training in the United Kingdom, it is nice to know that New Zealand is ahead of the game as far as conservation plans are concerned. The United Kingdom rarely uses conservation plans and their conservation decisions appear at times a little ad hoc. This is puzzling but perhaps it is because the country is so rich in historic buildings it can afford to be more casual in their approach. (As an indication of the sheer numbers of historic buildings in the UK, 2000 buildings a year are lost from the "At Risk" list). While the initiative for developing conservation plans arose in Australia, New Zealand has a more practical approach encompassing both the identification of significance as well as future action.

Philosophy for Repair and Change

When considering the repair and change of a building, there are a few key principles to keep in mind.

  1. Use traditional methods in traditional buildings and modern techniques in modern buildings. The cathedral is a good example of both types of construction. The nave is built using traditional techniques and it is important when repairing the stonework that only traditional methods are used. For example, if Portland cement is used as a mortar between the blocks it will form an impermeable barrier to the water that is continually moving through the limestone and the stone will deteriorate very fast. Using Portland mortar in limestone buildings can result in salt blasting off the surface of the stone as salt molecules, which form within the stone and are larger than the limestone molecules expand and fracture the outer surface.
  2. I like the description of the cathedral as part of creation, built out of limestone that was laid down in the Southern Ocean millions of years ago from the bodies of marine animals. The mortar used to join these blocks is part of another cycle known as the lime cycle. The mortar is made from limestone itself heated to a high temperature turned into quicklime to which water is added. This forms slurry to which sand is added and it is laid as mortar. Over time, carbon dioxide is absorbed from the atmosphere and its chemical makeup returns to that of pure limestone.
  3. Another advantage of lime mortar is that it is softer than modern materials. In an earthquake, it allows the building to move and to settle without cracking. Modern materials are more rigid and while they may withstand an earthquake, it a critical point the materials may fail.
  4. The preservation and development should be true to the history of the building. One advantage that New Zealand has over the United Kingdom is that its history is more tangible. There is usually someone living who knew something about the original builders, architects and users that can become part of the record of the building.
  5. Legislation and compliance requirements are continually changing. For example, in 2004 each council had to develop its own scheme for earthquake proofing historic buildings. The draft model for Dunedin may be on the conservative side but discussions are on going and the final model may be more relaxed.
  6. For a building such as the cathedral it would be appropriate to develop a 20 or 30-year plan that attempts to anticipate future use while remaining flexible. In developing the plan, the cathedral should clarify the Historic Places Trust classification and the Dunedin City Council's district plan to see whether the cathedral appears there as a registered item.
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