Edinburghs first new concert hall for a century had been expected to open this year but, according to report in The Herald, contractor Sir Robert McAlpine, which completed pre-construction works last year, has not been retained for the main building phase.Negotiations between the charity backing the project, the International Music and Performing Arts Charitable Trust Scotland (Impact), and McAlpine had been at an advanced stage.But Impacts chief executive, Jo Buckley, has now confirmed that it has decided to change contractors, stating that McAlpine would not be the right delivery partner to take us forward into main construction because of costs.AdvertisementShe told The Herald: Thats led to a pause on site in recent months. That followed the companys widely publicised withdrawal from Scotland and a real shift in their strategic priorities at a UK level.Buckley said Impacts objective as a charity was to secure best value for money on price and sadly we were no longer able to meet those requirements with McAlpines.The charity is now negotiating with Balfour Beatty with work paused until a new deal is signed.The concert hall, off St Andrew Square, will become the new home of the Scottish Chamber Orchestra and host Edinburgh International Festival performances.The projects cost has risen steeply, from an initial estimate of 45 million to 75 million in 2021 and 114 million towards the end of 2023.AdvertisementCity of Edinburgh Council approved Chipperfields design in November 2021. The practice is working with executive architect Reiach and Hall.The designs approved in 2021 were 7m shorter than previous consented proposals. The changes followed a legal challenge by Nuveen Real Estate, the developer of the neighbouring 80,000m St James shopping centre scheme.Chipperfield won an international competition to land the high-profile scheme in 2017, selected ahead of Adjaye Associates, Allies and Morrison, Richard Murphy Architects, Canadian practice KPMB Architects and Swiss firm Barozzi Veiga.Evolution of David Chipperfield Architects' designs: first iteration as released in early 2018 (left); designs as approved in 2019 (middle); revised proposals as submitted as a variation to the application in August 2021 and approved in November 2021 (right)