The mansion of the Crown Property Bureau on Rong Muang road in Pathumwan district is one of five sites receiving the Awards of Merit from the UN agency this year.
Others are Exeter Farm in New South Wales, Australia; Shri Sakhargad Niwasini Devi Temple Complex in Maharashtra, India; Frankton Boatshed in Queenstown, New Zealand; and Wak Hai Cheng Boi in Singapore.
"The restoration of the early 20th-century Phraya Si Thammathirat residence in Bangkok's Pathumwan district is a prime example of multiple-stakeholder commitment to the preservation of a building with significant heritage value," Unesco said in a statement released on Tuesday.
Phraya Si Thammathirat was a civil servant in the reign of King Rama VI, according to the Siam Society. His house was later sold to the bureau and the present tenant is the Thai-Chinese Education and Culture Foundation. It is in the compound of Sitabutr Bamrung School.
The bureau and the foundation have preserved the mansion in an effort praised by Unesco.
"The project renewed the landscape setting and exterior finishes and reinstated the rich interior treatment of the former private house, now housing Sitabutr Bamrung School. After restoration, the property enjoys a vibrant role as a centre for cultural exchange and education for the Thai-Chinese community," it said.
The Award of Merit is the third tier of the five-category Unesco Asia-Pacific Heritage Awards for Cultural Heritage Conservation. The top two awards are the Award of Excellence and Award of Distinction. The other two categories are Honourable Mention and Jury Commendation for Innovation Winners.
The mansion is one of 46 entries competing for the awards with 10 projects winning the contest this year.
No projects received the best award this year.
"Although there was no Award of Excellence given this year, there was an overall increase in projects awarded which gives hope for a general rise in the standards of heritage conservation by non‐state actors within the Asia‐Pacific region," said Tim Curtis, chair of the Jury and chief of the Culture Unit, Unesco, in Bangkok, said in the statement.