Owner Straidorn Properties is investing £7.5 million in the project. : Work is to begin this month to refurbish and fit-out Custom House, one of Belfast’s most iconic listed buildings. It will be transformed into grade A office accommodation by Mascott Construction, with work set to be completed by June 2022. Custom House was acquired last year by Straidorn Properties, the property investment arm of local businessman Neil McKibbin and his family, who have made an overall investment of £7.5 million to refurbish the 58,000 square feet of space.