I never noticed the plaque/inscription at the top of this building until today and the date is of interest as it indicates that the building existed before the Rathmines Township was created. Unfortunately, I cannot find any information specific to the building - are you in a position to help? 

The Rathmines Township was created in 1847 by Act of Parliament. Under the Rathmines and Rathgar Improvement Act, 1862, the townlands of Rathgar and Sallymount (the latter comprising present-day Ranelagh) were added to the re-named Rathmines and Rathgar Township, which was further extended in 1866 to include townlands in Uppercross. 

Milltown was added to the township under the Milltown Extension Act, 1880. Originally the township was governed by Commissioners, but under the Local Government (Ireland) Act of 1898 the Rathmines and Rathgar Urban District Council was established as the elected governing body. 

The Rathmines Township was created as a sanitary area, but new functions were added with each of the above acts, so that its duties came to include responsibility for public lighting and water supply as well as drainage, which was provided jointly with the Pembroke Township. After 1898, the Urban District Council built a number of small housing schemes, under legislation for housing of the working classes.