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Project Profile


2009 Award of Merit

Huai Hai Lu 796

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Technical Brief

Treatment of window frames and ironmongery items

To maintain the historic character of the neo-classical villas, special attention was given to retaining historic details such as the original window frames and ironmongery items (metal handles, stoppers and hinges). The frames were made of steel and the ironmongery items were made of copper alloy (brass).

Prior to the conservation work, investigation of paint layers and historical research concluded that the original color of both the interior and exterior window frames was white. This was also supported by the chromatic composition of the external facades. The research also found that the ironmongery items had not originally been painted.

When the conservation work began, both the frames and ironmongery items were in relatively good condition. The frames and ironmongery items were painted, however. Those on the exterior had been painted brown, while those on the exterior had been painted white. Some of the surfaces had suffered from slight alterations and a lack of maintenance, which had caused oxidation of the metals, and had affected the functionality of the windows.

For the restoration process, the steel frames and ironmongery had to be professionally treated to regain their functionality and original appearance. All the handles had to be re-engineered, and the window frames had to be cleaned and re-installed.

Before any action was taken, the windows and ironmongery were classified by surveyors, who identified three types of windows: (1) three-part windows with one double leaf window opening and side windows with a one leaf opening, (2) double windows with two leaf openings and a central handle, and (3) single windows with a one leaf opening and a side handle. Two types of handles were found: (1) handles for single leaf windows and (2) handles for double leaf windows.

The steel frames were catalogued and dismantled for cleaning. Each mechanical part (handles, stopper and sticks) was numbered to ensure that the system could be put back together appropriately after the cleaning processes. Existing paint was removed with the help of a paint remover applied with a brush and left on for 20 to 30 minutes. The surfaces were then treated with anti-rust protection and white enamel matte paint was used as a finish.

The surfaces of the handles and other ironmongery items were very delicate as they were a specific alloy. The process of restoring them began with the removal of the layers of paint applied in the past. All parts were put in a solution of nitro solvent for 24 to 48 hours. After this, the paint was removed with a soft cloth. To clean the ironmongery items of all dust particles, they were put into a solution of ammonium tartrate and left for 24 hours. Following this, they were washed with water and brushed with a hard toothbrush. All the parts were then treated with a chemical, benzotriazol mixed with 3 percent ethyl alcohol, to inhibit erosion, and were subsequently treated with a protective product, namely paraloid B44. Finally, all the mechanical parts were well greased.

Adapted from “Huai Hai Lu” UNESCO Asia-Pacific Heritage Awards entry submission