The newly opened Welsh assembly building - the Senedd - will have to undergo repairs after the roof began leaking in heavy rain.
The roof of the £67m building has begun to leak
After several days of rain in Cardiff, puddles have appeared inside the £67m Richard Rogers-designed building, which was opened by the Queen on 1 March.
An assembly spokeswoman said repair costs would be covered by the builders.
Last week, the Scottish Parliament was evacuated after a beam slipped and was left hanging from the roof.
The £430m building, which opened in 2004, has not been declared safe and the Scottish Parliament has been forced to hold debates in the Hub - a former church used for the Edinburgh International Festival - while repairs are carried out.
On Wednesday problems also emerged at the Senedd building in Cardiff Bay which provides a debating chamber for the 60 assembly members as well as other rooms.
Constructed on "green" principles with renewable energy systems intended to reduce running costs by up to half, the features include steel columns which collect rainwater from the roof to supply the toilets and to wash the windows.
Exactly a week after it was opened by the Queen, leaks have sprung at various points including the public gallery and access corridors.
An assembly spokeswoman said repair costs would be covered by the fixed contract with the builders.
"It won't be paid for by ourselves," she said.