This building is the spired hall. The Vihara Yod was build in the reign of King
Rama III. The door of this hall ornamented with the mother pearl is in the late Ayutthaya period. The spired Hall was made to contain a large standing Buddha
image named “Phra Naga”. This image Had been moved down from Ayutthaya. It now serves as a chapel for the Phra Naka image.

source : Tourist Guide to Thailand book,Thailand-sawasdee.blogspot.com