South Africa's Chief Justice Mogoeng Mogoeng on Thursday ordered President Jacob Zuma pay back the state back for "non-security features" added on to his private residence, settling a scandal that resulted in calls for his resignation.

"The president thus failed to uphold, defend and respect the constitution," the chief justice said during the reading of the Constitutional Court's ruling.

Mogoeng said Public Protector Thuli Madonsela's report that Zuma misappropriated state funds to pay for additions and renovations made to his Nkandla homestead and her prescribed remedial actions were "binding."

'Unlawful'

In 2014, Madonsela said some of the upgrades to Zuma's residences were "unlawful" and constituted "improper conduct and maladministration."

The national treasury has 60 days from the court ruling to stipulate the amount Zuma is liable to repay to the public works department.

After the treasury reports the amount due, Zuma has 45 days to "personally" repay for the upgrades. The determined amount will be a percentage of the total costs incurred for the residential improvements.

The chief justice also announced that a National Assembly resolution absolving Zuma of responsibility for the affair was "inconsistent with the constitution" and consequently "invalid."

Impeachment on the table

Following the ruling, the leader of South Africa's Democratic Alliance (DA) said opposition lawmakers initiated the process to impeact Zuma.

"If I was Zuma, I would be preparing my letter of resignation," said DA chief Mmusi Maimane.

In the past year, Zuma has been embroiled by several challenges, including allegations of widespread government corruption and mass protests calling for his removal.