Experts are preparing to repair cracks that have appeared in the slabs that make up Berlin's Holocaust memorial since the monument opened in 2005. Blue canvas covers have been draped over a few of the memorial's 2,711 slabs to dry them out and protect them from rain, Felizitas Borzym, an official with the foundation that oversees the monument, said Wednesday. Workers are to inject the gray concrete slabs with a special resin in the next few days in an effort to seal the cracks. The foundation said last month that as many as 1,900 slabs have cracks, although some have only extremely minor damage. The memorial opened to the public in May 2005. Cracks in several hundred slabs emerged last year; earlier this year, an expert suggested that the cause might be weather-induced tensions inside the slabs. Other possible causes that have been suggested are vibrations from a nearby building site and a suburban railway tunnel. Officials have chosen slabs with five different degrees of damage for the first repairs, to test out the sealing method. It was not immediately clear how much the repairs might cost or how long they would take. The company that built the memorial is taking on the cost of repairing the first 50 slabs. Designed by the American architect Peter Eisenman, the memorial _ located close to Berlin's signature Brandenburg Gate _ cost â‚¬27.6 million (US$43.4 million) to build. The site is open to the public around the clock.