Patna, Nov. 23: Engineers have used pressurised grouting to solve the water seepage problem in the basement of the five-floor swanky extension of the Bihar legislature.

The extension building has been constructed for Rs 362 crore. The basement - which will have three halls with a of 200, 300 and 550 people, respectively - was on hold because of the water seepage but as that has been taken care of now, the building construction department overseeing the project hopes to finish the work by March 2017 in time for the budget session.

"A team of experts from IIT-Roorkee had suggested massive grouting in which a mixture of mortar and chemicals is forcibly injected to obstruct the porosity of the cross section and stop the inward flow of water," principal secretary, building construction, Amrit Lal Meena told The Telegraph today. "We did it and found it to be successful."

The IIT team had suggested the building construction department to wait and watch during monsoon, when the water table rises, if the grouting procedure had worked. No seepage was detected then.

The report will be sent to IIT-Roorkee in 10 days.

Further steps suggested by the team include sinking of tubewells outside the basement and will be undertaken to ensure there is no water seepage in the future.

The extension building, a pet project of chief minister Nitish Kumar, and designed on the lines of the Central Hall of Parliament, was inaugurated on November 19 to resolve space crunch at the Legislative Assembly and Legislative Council and manifold increase in legislators' work and activities.

The foundation stone of the extension building was laid on January 26, 2010, and construction was completed in 2012. Inaugurating the extension building on November 19, Nitish had announced with joy that the water seepage problem in the basement has been resolved.

Amrit Meena, the building construction principal secretary, said two of the smaller halls in the basement 4.5m deep had no seepage problem. The biggest hall with a depth of 9m suffered from it.

"The basement was constructed in 2012 and the seepage was detected in 2014," he added. "Experts said it was because of the very high water table in the area, which was at a depth of 7m."

Building construction engineers said tenders will be announced for finishing touches to the three halls so that they are ready as soon as possible.