Two period buildings, expensively refurbished and converted into offices at Mount Saint Anne’s in Milltown, Dublin 6, have been sold to investors who will be able to avail of the capital gains tax exemption before it runs out at the end of this month.

An overseas businessman has paid €3.4 million for the chapel building while an Irish investor has completed the purchase of Milltown House at €2.2 million. Colm Luddy of CBRE marketed the two properties as "trophy assets" of a kind that seldom come on the market.

The 1880s chapel has 1,096 sq m (11,806 s q ft) of air-conditioned office space over three levels. The restoration work was overseen by architects O’Mahony Pike which occupies part of the building. The other tenants are Comsys and Rojo Management Consultants. One of the leases runs for four years and 10 months and the other for 10 years up to 2023.

The overall rent roll of €196,292 has obvious potential for growth, according to CBRE which predicts that prime rents in the city centre will rise by 22 per cent to €592 per sq m (€55 per sq ft) by the end of next year. At the current valuation of €3.4 million, the new owner of the chapel can bank on an initial return of 5.5 per cent.

The chapel is frequently cited as one of the best examples in the city of how a period building can be converted into a modern, adaptable office complex without interfering with the integrity or appearance of the original building. This was achieved by inserting a free-standing steel structure into the body of the church to accommodate three floors of offices.

Milltown House, a four-storey building dating from 1760, has also been skilfully restored and retains its most important features, including ornate plasterwork and staircases. It is currently producing a rent roll of €155,000 from 660sq m (7,114 sq ft). The 25-year lease has about 17 years to run. The next rent review is due in 2017. The chapel has 14 car-parking spaces while Milltown House comes with 10.

Mount Saint Anne's was originally a religious mother house and a working farm for an order of nuns.The campus also included a primary and secondary school. Most of the Mount Saint Anne's site was acquired in the 1990s by Michael Cotter's Park Developments which went on to develop his most successful residential scheme, which included 480 high-value apartments and 170 family homes.