Much of the square became tenements from the 1800s when the south side of the city became more fashionable. By the 1960s, large portions of the Square were in such poor condition that many were condemned and demolished as dangerous. Half of the south side of the Square was bought up by Leinster Estates, a company owned by the property developer Matt Gallagher, in the early 1970s. His plan was to build a large office block designed by Desmond FitzGerald. Despite high objections from the Irish Georgian Society (IGI), permission for the office block scheme was granted in October 1967. After a public inquiry, Gallagher offered to sell his land with 7 standing houses and 13 demolished or partly demolished houses to the IGI for £68,000. Despite the formation of Mountjoy Square Estates in an attempt to take up Gallagher's offer, permission was granted for the office scheme again in July 1969. This stipulated that all of the house facades be reinstated, which called into question the financial viability of the project. This led to Mountjoy Square Estates purchasing the plots in December 1969 for £68,000 with the condition that all the houses would be restored individually, and all adhere to the Georgian aesthetic. However, the group could not secure the funds or purchasers willing to restore the buildings, and then continued to decay. After brickwork began to fall into the street, Dublin Corporation demolished many of the houses to first floor level for safety reasons. In June 1972, the plot was sold to Patrick McCrea. McCrea began work on the site redeveloping it with a Georgian facade, but he ran out of funds. Following his death, the site remained untouched until 1978 when it was purchased by Stephen Treacy, though he failed to progress the project and by 1981 parts of brick cladding from the 1970s construction fell into the street, crushing two cars. Eventually the whole site was developed with a replica Georgian facade designed by Sean Clifford and Associates.