Building restoration
From Wikipedia, the free encyclopedia
Building restoration describes the process of the renewal and refurbishment of the fabric of a building. The phrase covers a wide span of activities, from the cleaning of the interior or exterior of a building - such as is currently underway at St Paul's Cathedral in London - to the rebuilding of damaged or derelict buildings, such as the restoration of the Windsor Great Hall in Windsor Castle after a destructive fire in 1992. The 1985–1989 removal of 38 layers of paint and the cleaning and repair of the extrior sandstone walls of the White House in the U.S. are an example of building restoration.
Buildings are structures which have, from time to time, particular purposes. They require ongoing maintenance to prevent them falling into disrepair as a result of the ravages of time and use. Building restoration can be thought of as that set of activities which are greater than year-to-year maintenance, but which by retaining the building are less than a demolition and the construction of a new building.
The scope of restoration depends upon the need, and other circumstances, such as the status of the building, and the affordability of the work required. There are three main types of restoration:
- Building cleaning - most especially cleaning the external facade of a building, and typically needed in cities that have suffered from smoke pollution. Many granite, sandstone, and limestone buildings in the UK, for example, have for most of their existence been black in colour owing to smoke and smog. Many, in turn, have been cleaned after air pollution legislation diminished the incidence of airborne particulate matter.
- Major repair - especially to stonework affected by acid rain and other pollutants, and which has weathered or decayed to a structurally unsound or aesthetically displeasing condition.
- Rebuilding to replace severely damaged or missing parts of a building. Here, in all cases, a balance is to be struck between recreation of the original building using materials and techniques similar to the original construction, as happened at very great expense at Windsor Castle; and the use of more modern techniques and materials.
Not all building restoration seeks to follow the original design of the building. It is reasonably commonplace for the shell of a building - its external walls - to be retained whilst an entirely new building is constructed within. This approach is aslo referred to as adaptive reuse.
Although techniques of restoration are improving, the action of cleaning or repairing buildings can, with hindsight, be seen to cause problems that at the time were unforeseen. A good example is the unrestrained use of sandblasting to clean smog deposits from soft-stoned buildings - a technique employed in the UK in the 1960s and 1970s - which has damaged the external faces of stonework to the extent that in some cases, later, the stonework has needed to be replaced. Contemporary building codes recognise such problems, and (it is to be hoped) mitigate poor outcomes.
[edit] Heritage Restoration
In the field of historic preservation, building restoration can refer to the action or process of accurately revealing, recovering or representing the state of a historic building, as it appeared at a particular period in its history, while protecting its heritage value. Work is often performed to reverse decay, or alterations made to the building after its initial construction. A part of heritage restoration can involve the replacement of outdated heating and cooling systems with newer ones, or the installation of climate controls that never existed at the time of building. Tsarskoye Selo, the complex of former royal palaces outside St. Petersburg in Russia are an example of this sort of work. Physical materials of an earlier time, that might have been state of the art at the time of construction, might have failed and now need replacement with contemporary better functioning, but aesthetically similar materials. Restoration of buildings at the Bauhaus in Dessau, Germany corrected a failed c. 1925 peat composition roof.
Exterior and interior paint colors present similar problems over time. Air pollution, acid rain, and sun take a toll, and often many layers of non-original paints are applied before an attempt at restoration is made. Color spectrum analysis of old paint now allows a corresponding chemical recipe to be produced. But this is often only a beginning as many of the original materials are either unstable or in many cases environmentally unsound. Many eighteenth century greens were made with arsenic, a material no longer allowed in paints. Another problem occurs when the original pigment came from a material no longer available. In the early to mid-nineteenth century ground mummy parts were used in making some browns. In this case organizations like Britain's National Trust for Places of Historic Interest or Natural Beauty will work with an historic paint color recreator like Farrow and Ball to replicate the antique color in durable, stable, and environmentally safe materials. In the United States the National Trust for Historic Preservation works similarly with Fine Paints of Europe a small manufacturer located in the U.S. state of Vermont that uses mostly Dutch and Swedish pigments and binders. The polychrome painted interiors of the Vermont State House and Boston Public Library are examples of this type of heritage restoration.
