Wat Arun, one of the kingdom's most famous landmarks, known for the morning light reflecting off its porcelain-encrusted surfaces, will remain open to visitors during the overhaul, according to officials.
"We will not close it all. The repairs will start in some parts only," a senior monk at the temple, Phra Sri Suthi Wethee, told AFP.
"Tourists can still come. We haven't closed the big stupa yet."
Work on the central tower -- built in the first half of the 19th century -- will start in 2015, according to Tharapong Srisuchat, a senior official at the Ministry of Culture.
"We cannot put all the scaffolding up at the same time or tourists will be disappointed," he said.
Tharapong estimated that it will take about a year to renovate the Khmer-style central stupa.
The budget for the project, which will start this month, is 130 million baht ($4.2 million), he added.
"The maintenance cycle is usually 25-30 years but it's shortening because of increased pollution and more severe changes in the weather," Tharapong said.
He said the work at the temple -- which was last renovated in 1996 -- would include repairing cracks, removing mould and replacing damaged tiles.