They Battle Time, And Win

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So, what are the problems St. Petersburgs restorers tackle when dealing with the citys building facades? We asked Sergei A. Shadrin, Senior Process Specialist at SPETS-PROYEKTRESTAVRATSIYA, the research institute for restoration. What were dealing with is what our predecessors with their notion of restoration have left us over the past few decades. Building facades have never really been restored, but given a facelift instead. In fact, most have been simply repainted, so now they are out on a limb. Therefore, our current focus in restoration is to relieve the pressure on the decorative protective finishing or stone facing. Following a careful study at our institutes lab, we pinpoint the problem areas on a building faade; then we find out what materials it was made of, and what materials were used in previous restorations. Our lab determines the paints and colorations that were used, and profiles their characteristics. Eventually we design a restoration solution, which is then applied in the field. We use special materials and paints to restore historical landmarks. Russian producers have by now learned how to make restoration mortars good enough for us. We never had them before, so our artists did not know how to handle them. Now that there are quality restoration supplies on the market things are improving. Some of our new materials are lime mortars. They are easier and faster to work with, and assure better quality. Sometimes its difficult to turn the workers on to new materials. They have a hard time giving up cement. On the other hand, there is no domestically produced quality paints, varnishes or primers, only imported ones. We have only just started to apply stone conservation products. It is essential, Shadrin told us, to diagnose the condition of the property right, and to set a realistic time frame. He cited one example to show how seriously his institute takes restoration research. Before the work commenced, Spetsproyektrestavratsiya experts tested sample facing materials taken from several city faades. Petrographic testing revealed that the facades had been plastered with a lime-based construction mortar with a mix of quartz/anorthite sand and brown limestone as filler. The faades were originally painted using lime-based binders. Later on, over a period of about 160 years, the buildings underwent numerous repairs and facelifts where their faade surfaces and plaster decorations were repainted using paints formulated with different binding agents. Further analysis revealed elements and surfaces where the original lime-based stucco mortar had been fully or partially replaced by a construction mortar containing cement, which does not go well with stucco finishing. Therefore, before a new restoration could begin, we had to fully remove all traces of cement-based construction mortar from the brickwork, including the spots where those mortars had been applied directly to lime stucco. The diagnosis and advice of Spetsproyektrestavratsiya experts proved correct, but scientists have no power to predict how long the work will take. Some think that the unbearable time pressure in the run-up towards the tercentenary justifies any means to a successful end. It is really hard to make contractors comply with high restoration standards when they are scrambling to meet inhuman deadlines. One typical example are the paints used in restoration. Russian scientists believe that, despite their numerous plusses, acrylic and pliolithic (resin-based) paints have one big defect: in a humid climate such as St. Petersburgs they fail to support an ideal balance of heat and humidity. This may, at some point, cause the walls to crumble, especially in older buildings.

: 12.11.2002
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