Narud Fowdar, who has owned the hotel since 1996, secured funding from Allied Irish Bank (GB) to buy the building and link the properties with a corridor.
The hotelier, who also owns the Corstorphine Lodge Hotel and Edinburgh City Suites, said the move was due to continued demand. A total of 14 ensuite bedrooms and a beer garden have been added while parking has been increased to accommodate 25 cars.
Fowdar commented: “The Cumberland Hotel now comprises two listed buildings, 35 bedrooms, two bars, a large dining room and extensive beer gardens.
“We’ve worked with Allied Irish Bank (GB) for 25 years. They helped us purchase the Cumberland Hotel back in 1996 and since then have consistently supported our acquisition and expansion plans.
“This has been a long-term project. We are in a conservation area and both hotel buildings are of architectural interest, so we had to ensure our plans were sympathetic to the buildings and maintained their character.
“There is a huge demand for rooms in this part of the city, and this extension will help us meet some of that need.”
Tina Crookston, relationship manager at Allied Irish Bank (GB), said: “When the opportunity arose for the Cumberland Hotel team to buy the adjacent property, we knew it was an attractive investment option."