Belfast's Waterfront Hall extension to cost £10m more 28 March 2013 Last updated at 06:12 The projected cost of Belfast City Council's proposed extension to the Waterfront Hall has risen by £10m. Last year, the council said the expected cost would be about £20m, however this has now risen to £30m. It is planning to extend the Waterfront Hall by adding extra exhibition and conference facilities to the side of the building. The extension is aimed at attracting major international conferences to the city. Following a subsequent study, the council has said the overall cost of the extension will now be £30m. It believes a building costing less than this would not meet the demands of the conference and exhibition market.