A 17th century communal house (dinh) on the outskirts of Hanoi that won the highest prize in the heritage preservation category at the International Union of Architects in Xi'an, China, last month, has officially reopened after months of restoration.

"The model restoration project aimed to duplicate as best as possible the original design," said Tran Lam Ben from the Cultural Heritage Department. "However, there has been some improper restoration work, which we will ask the workers to fix later."

According to architect Le Thanh Vinh, who headed the restoration team, the work was extremely intricate.

"We first had to conduct very careful research on all the relics to gauge what sort of condition they were in," he said.

Ultra-sound equipment was used to check the condition of the house's wooden pillars, he said.

Chu Quyen Communal House's 48 wooden pillars were damaged by weathering. However, only two had to be replaced, Vinh said.

The original house roof was made up of 51 different kinds of tiles. Restorers said 48,000 of the original tiles were saved. Those that needed to be replaced were produced using traditional methods of baking clay over straw.

Because of efforts to duplicate the original design, the work took twice as long as normal, Vinh said.

The restoration beat 33 entries from 14 countries in the Asia Pacific region to win the architects' award – the first Vietnam has won.

The communal house, more commonly referred to as the Chang Communal House, is in Hanoi's Ba Vi district. It consists of a room, largely constructed of wood, for worship.

The house was recognised as a historical site in 1962. Restoration on the house began in 2007.

Tran Chien Thang, Deputy Minister of Culture, said the project would serve as the standard for other restoration work./.