By Liz White, UT staffCavan, Ireland- A new feature of the skyline in Welsh city Cardiff is the 23-storey Altolusso development, topped by an unusual roof, insulated using a rigid polyurethane foam-based product. "Durable, thermal efficiency for the tallest residential building in the city," is the result of a high-performance tapered flat-roof insulation system from Kingspan Insulation, the Cavan headquartered group said in a press announcement. Contractors Roofbond Restoration installed a Fatrafol membrane along with the Thermataper TT47 rigid urethane insulation from Kingspan. The polyurethane system used is blown with an agent which is free from chlorofluorocarbons or hydrochlorofluorocarbons and offers zero ozone-depletion potential, Kingspan said. The roof of this project resembles a three-leaved clover shape when seen from above, according to Kingspan, which points out that such an "unusual roof configuration could have caused problems. " But the insulation supplier says its Thermataper systems "offer great flexibility, and come with a first class-design package."Thermatur roofing has been designed to prevent water ponds forming-a common cause of leaking flat roofs-by giving effective roof falls, said the manufacturer. Preventing the build-up of rainwater increases flat roof life because such water can cause thermal stress, alkali formation and mould growth on the membrane, Kinspan points out. Thermatur, which can be installed on both new and existing flat roofs, is designed to be used under fully adhered single-ply waterproofing, and ensures low heat loss through the roof. Its thermal conductivity of 0.027 W/m.K gives "the U-values required for compliance with building regulations," Kingspan said. The Altolusso (Italian for 'high living') development was designed by Architects Holder Mathias Alcock plc for Redrow Homes. Kingspan said it has "spectacular views of the city and of Cardiff Bay," from many of its 292 apartments. It was built on the site of the former New College in Bute Terrace, and the original Victorian façade has been retained, forming a novel three-storey entrance foyer. "